X-Git-Url: https://git.tcpdump.org/libpcap/blobdiff_plain/3df4925c28ee213aff7e526bbfb67cb79ddc6fef..refs/heads/libpcap-1.3:/pcap-linux.c diff --git a/pcap-linux.c b/pcap-linux.c index 43e3a388..e5c3afa7 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -30,11 +30,44 @@ * based on previous works of: * Simon Patarin * Phil Wood + * + * Monitor-mode support for mac80211 includes code taken from the iw + * command; the copyright notice for that code is + * + * Copyright (c) 2007, 2008 Johannes Berg + * Copyright (c) 2007 Andy Lutomirski + * Copyright (c) 2007 Mike Kershaw + * Copyright (c) 2008 Gábor Stefanik + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. */ #ifndef lint static const char rcsid[] _U_ = - "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.142 2008-04-07 00:31:47 guy Exp $ (LBL)"; + "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.164 2008-12-14 22:00:57 guy Exp $ (LBL)"; #endif /* @@ -80,34 +113,36 @@ static const char rcsid[] _U_ = */ +#define _GNU_SOURCE + #ifdef HAVE_CONFIG_H #include "config.h" #endif #include +#include #include +#include #include #include #include +#include +#include #include #include #include #include -#include +#include +#include #include #include #include #include - -/* - * Got Wireless Extensions? - */ -#ifdef HAVE_LINUX_WIRELESS_H -#include -#endif +#include #include "pcap-int.h" #include "pcap/sll.h" +#include "pcap/vlan.h" #ifdef HAVE_DAG_API #include "pcap-dag.h" @@ -117,6 +152,10 @@ static const char rcsid[] _U_ = #include "pcap-septel.h" #endif /* HAVE_SEPTEL_API */ +#ifdef HAVE_SNF_API +#include "pcap-snf.h" +#endif /* HAVE_SNF_API */ + #ifdef PCAP_SUPPORT_USB #include "pcap-usb-linux.h" #endif @@ -125,6 +164,18 @@ static const char rcsid[] _U_ = #include "pcap-bt-linux.h" #endif +#ifdef PCAP_SUPPORT_CAN +#include "pcap-can-linux.h" +#endif + +#if PCAP_SUPPORT_CANUSB +#include "pcap-canusb-linux.h" +#endif + +#ifdef PCAP_SUPPORT_NETFILTER +#include "pcap-netfilter-linux.h" +#endif + /* * If PF_PACKET is defined, we can use {SOCK_RAW,SOCK_DGRAM}/PF_PACKET * sockets rather than SOCK_PACKET sockets. @@ -165,6 +216,9 @@ static const char rcsid[] _U_ = */ # ifdef PACKET_HOST # define HAVE_PF_PACKET_SOCKETS +# ifdef PACKET_AUXDATA +# define HAVE_PACKET_AUXDATA +# endif /* PACKET_AUXDATA */ # endif /* PACKET_HOST */ @@ -173,6 +227,11 @@ static const char rcsid[] _U_ = * uses many ring related structs and macros */ # ifdef TPACKET_HDRLEN # define HAVE_PACKET_RING +# ifdef TPACKET2_HDRLEN +# define HAVE_TPACKET2 +# else +# define TPACKET_V1 0 +# endif /* TPACKET2_HDRLEN */ # endif /* TPACKET_HDRLEN */ #endif /* PF_PACKET */ @@ -181,6 +240,46 @@ static const char rcsid[] _U_ = #include #endif +/* + * We need linux/sockios.h if we have linux/net_tstamp.h (for time stamp + * specification) or linux/ethtool.h (for ethtool ioctls to get offloading + * information). + */ +#if defined(HAVE_LINUX_NET_TSTAMP_H) || defined(HAVE_LINUX_ETHTOOL_H) +#include +#endif + +#ifdef HAVE_LINUX_NET_TSTAMP_H +#include +#endif + +/* + * Got Wireless Extensions? + */ +#ifdef HAVE_LINUX_WIRELESS_H +#include +#endif /* HAVE_LINUX_WIRELESS_H */ + +/* + * Got libnl? + */ +#ifdef HAVE_LIBNL +#include + +#include +#include +#include +#include +#include +#endif /* HAVE_LIBNL */ + +/* + * Got ethtool support? + */ +#ifdef HAVE_LINUX_ETHTOOL_H +#include +#endif + #ifndef HAVE_SOCKLEN_T typedef int socklen_t; #endif @@ -219,14 +318,14 @@ typedef int socklen_t; /* * Prototypes for internal functions and methods. */ -static void map_arphrd_to_dlt(pcap_t *, int, int); +static void map_arphrd_to_dlt(pcap_t *, int, int, const char *, int); #ifdef HAVE_PF_PACKET_SOCKETS static short int map_packet_type_to_sll_type(short int); #endif static int pcap_activate_linux(pcap_t *); static int activate_old(pcap_t *); static int activate_new(pcap_t *); -static int activate_mmap(pcap_t *); +static int activate_mmap(pcap_t *, int *); static int pcap_can_set_rfmon_linux(pcap_t *); static int pcap_read_linux(pcap_t *, int, pcap_handler, u_char *); static int pcap_read_packet(pcap_t *, pcap_handler, u_char *); @@ -234,18 +333,27 @@ static int pcap_inject_linux(pcap_t *, const void *, size_t); static int pcap_stats_linux(pcap_t *, struct pcap_stat *); static int pcap_setfilter_linux(pcap_t *, struct bpf_program *); static int pcap_setdirection_linux(pcap_t *, pcap_direction_t); -static void pcap_close_linux(pcap_t *); +static void pcap_cleanup_linux(pcap_t *); + +union thdr { + struct tpacket_hdr *h1; + struct tpacket2_hdr *h2; + void *raw; +}; #ifdef HAVE_PACKET_RING -#define RING_GET_FRAME(h) (((struct tpacket_hdr**)h->buffer)[h->offset]) +#define RING_GET_FRAME(h) (((union thdr **)h->buffer)[h->offset]) static void destroy_ring(pcap_t *handle); -static int create_ring(pcap_t *handle); -static void pcap_close_linux_mmap(pcap_t *); +static int create_ring(pcap_t *handle, int *status); +static int prepare_tpacket_socket(pcap_t *handle); +static void pcap_cleanup_linux_mmap(pcap_t *); static int pcap_read_linux_mmap(pcap_t *, int, pcap_handler , u_char *); static int pcap_setfilter_linux_mmap(pcap_t *, struct bpf_program *); static int pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf); static int pcap_getnonblock_mmap(pcap_t *p, char *errbuf); +static void pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h, + const u_char *bytes); #endif /* @@ -253,19 +361,23 @@ static int pcap_getnonblock_mmap(pcap_t *p, char *errbuf); */ #ifdef HAVE_PF_PACKET_SOCKETS static int iface_get_id(int fd, const char *device, char *ebuf); -#endif +#endif /* HAVE_PF_PACKET_SOCKETS */ static int iface_get_mtu(int fd, const char *device, char *ebuf); static int iface_get_arptype(int fd, const char *device, char *ebuf); #ifdef HAVE_PF_PACKET_SOCKETS static int iface_bind(int fd, int ifindex, char *ebuf); -static int has_wext(int sock_fd, const char *device); -static int enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, +#ifdef IW_MODE_MONITOR +static int has_wext(int sock_fd, const char *device, char *ebuf); +#endif /* IW_MODE_MONITOR */ +static int enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device); -#endif +#endif /* HAVE_PF_PACKET_SOCKETS */ +static int iface_get_offload(pcap_t *handle); static int iface_bind_old(int fd, const char *device, char *ebuf); #ifdef SO_ATTACH_FILTER -static int fix_program(pcap_t *handle, struct sock_fprog *fcode); +static int fix_program(pcap_t *handle, struct sock_fprog *fcode, + int is_mapped); static int fix_offset(struct bpf_insn *p); static int set_kernel_filter(pcap_t *handle, struct sock_fprog *fcode); static int reset_kernel_filter(pcap_t *handle); @@ -274,13 +386,19 @@ static struct sock_filter total_insn = BPF_STMT(BPF_RET | BPF_K, 0); static struct sock_fprog total_fcode = { 1, &total_insn }; -#endif +#endif /* SO_ATTACH_FILTER */ pcap_t * pcap_create(const char *device, char *ebuf) { pcap_t *handle; + /* + * A null device name is equivalent to the "any" device. + */ + if (device == NULL) + device = "any"; + #ifdef HAVE_DAG_API if (strstr(device, "dag")) { return dag_create(device, ebuf); @@ -293,43 +411,566 @@ pcap_create(const char *device, char *ebuf) } #endif /* HAVE_SEPTEL_API */ +#ifdef HAVE_SNF_API + handle = snf_create(device, ebuf); + if (strstr(device, "snf") || handle != NULL) + return handle; + +#endif /* HAVE_SNF_API */ + #ifdef PCAP_SUPPORT_BT if (strstr(device, "bluetooth")) { return bt_create(device, ebuf); } #endif +#if PCAP_SUPPORT_CANUSB + if (strstr(device, "canusb")) { + return canusb_create(device, ebuf); + } +#endif + +#ifdef PCAP_SUPPORT_CAN + if ((strncmp(device, "can", 3) == 0 && isdigit(device[3])) || + (strncmp(device, "vcan", 4) == 0 && isdigit(device[4]))) { + return can_create(device, ebuf); + } +#endif + #ifdef PCAP_SUPPORT_USB - if (strstr(device, "usb")) { + if (strstr(device, "usbmon")) { return usb_create(device, ebuf); } #endif +#ifdef PCAP_SUPPORT_NETFILTER + if (strncmp(device, "nflog", strlen("nflog")) == 0) { + return nflog_create(device, ebuf); + } +#endif + handle = pcap_create_common(device, ebuf); if (handle == NULL) return NULL; handle->activate_op = pcap_activate_linux; handle->can_set_rfmon_op = pcap_can_set_rfmon_linux; +#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) + /* + * We claim that we support: + * + * software time stamps, with no details about their precision; + * hardware time stamps, synced to the host time; + * hardware time stamps, not synced to the host time. + * + * XXX - we can't ask a device whether it supports + * hardware time stamps, so we just claim all devices do. + */ + handle->tstamp_type_count = 3; + handle->tstamp_type_list = malloc(3 * sizeof(u_int)); + if (handle->tstamp_type_list == NULL) { + free(handle); + return NULL; + } + handle->tstamp_type_list[0] = PCAP_TSTAMP_HOST; + handle->tstamp_type_list[1] = PCAP_TSTAMP_ADAPTER; + handle->tstamp_type_list[2] = PCAP_TSTAMP_ADAPTER_UNSYNCED; +#endif + return handle; } +#ifdef HAVE_LIBNL +/* + * If interface {if} is a mac80211 driver, the file + * /sys/class/net/{if}/phy80211 is a symlink to + * /sys/class/ieee80211/{phydev}, for some {phydev}. + * + * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at + * least, has a "wmaster0" device and a "wlan0" device; the + * latter is the one with the IP address. Both show up in + * "tcpdump -D" output. Capturing on the wmaster0 device + * captures with 802.11 headers. + * + * airmon-ng searches through /sys/class/net for devices named + * monN, starting with mon0; as soon as one *doesn't* exist, + * it chooses that as the monitor device name. If the "iw" + * command exists, it does "iw dev {if} interface add {monif} + * type monitor", where {monif} is the monitor device. It + * then (sigh) sleeps .1 second, and then configures the + * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface + * is a file, it writes {mondev}, without a newline, to that file, + * and again (sigh) sleeps .1 second, and then iwconfig's that + * device into monitor mode and configures it up. Otherwise, + * you can't do monitor mode. + * + * All these devices are "glued" together by having the + * /sys/class/net/{device}/phy80211 links pointing to the same + * place, so, given a wmaster, wlan, or mon device, you can + * find the other devices by looking for devices with + * the same phy80211 link. + * + * To turn monitor mode off, delete the monitor interface, + * either with "iw dev {monif} interface del" or by sending + * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface + * + * Note: if you try to create a monitor device named "monN", and + * there's already a "monN" device, it fails, as least with + * the netlink interface (which is what iw uses), with a return + * value of -ENFILE. (Return values are negative errnos.) We + * could probably use that to find an unused device. + * + * Yes, you can have multiple monitor devices for a given + * physical device. +*/ + +/* + * Is this a mac80211 device? If so, fill in the physical device path and + * return 1; if not, return 0. On an error, fill in handle->errbuf and + * return PCAP_ERROR. + */ static int -pcap_can_set_rfmon_linux(pcap_t *p) +get_mac80211_phydev(pcap_t *handle, const char *device, char *phydev_path, + size_t phydev_max_pathlen) { + char *pathstr; + ssize_t bytes_read; + + /* + * Generate the path string for the symlink to the physical device. + */ + if (asprintf(&pathstr, "/sys/class/net/%s/phy80211", device) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't generate path name string for /sys/class/net device", + device); + return PCAP_ERROR; + } + bytes_read = readlink(pathstr, phydev_path, phydev_max_pathlen); + if (bytes_read == -1) { + if (errno == ENOENT || errno == EINVAL) { + /* + * Doesn't exist, or not a symlink; assume that + * means it's not a mac80211 device. + */ + free(pathstr); + return 0; + } + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't readlink %s: %s", device, pathstr, + strerror(errno)); + free(pathstr); + return PCAP_ERROR; + } + free(pathstr); + phydev_path[bytes_read] = '\0'; + return 1; +} + +#ifdef HAVE_LIBNL_2_x +#define get_nl_errmsg nl_geterror +#else +/* libnl 2.x compatibility code */ + +#define nl_sock nl_handle + +static inline struct nl_handle * +nl_socket_alloc(void) +{ + return nl_handle_alloc(); +} + +static inline void +nl_socket_free(struct nl_handle *h) +{ + nl_handle_destroy(h); +} + +#define get_nl_errmsg strerror + +static inline int +__genl_ctrl_alloc_cache(struct nl_handle *h, struct nl_cache **cache) +{ + struct nl_cache *tmp = genl_ctrl_alloc_cache(h); + if (!tmp) + return -ENOMEM; + *cache = tmp; + return 0; +} +#define genl_ctrl_alloc_cache __genl_ctrl_alloc_cache +#endif /* !HAVE_LIBNL_2_x */ + +struct nl80211_state { + struct nl_sock *nl_sock; + struct nl_cache *nl_cache; + struct genl_family *nl80211; +}; + +static int +nl80211_init(pcap_t *handle, struct nl80211_state *state, const char *device) +{ + int err; + + state->nl_sock = nl_socket_alloc(); + if (!state->nl_sock) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: failed to allocate netlink handle", device); + return PCAP_ERROR; + } + + if (genl_connect(state->nl_sock)) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: failed to connect to generic netlink", device); + goto out_handle_destroy; + } + + err = genl_ctrl_alloc_cache(state->nl_sock, &state->nl_cache); + if (err < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: failed to allocate generic netlink cache: %s", + device, get_nl_errmsg(-err)); + goto out_handle_destroy; + } + + state->nl80211 = genl_ctrl_search_by_name(state->nl_cache, "nl80211"); + if (!state->nl80211) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl80211 not found", device); + goto out_cache_free; + } + + return 0; + +out_cache_free: + nl_cache_free(state->nl_cache); +out_handle_destroy: + nl_socket_free(state->nl_sock); + return PCAP_ERROR; +} + +static void +nl80211_cleanup(struct nl80211_state *state) +{ + genl_family_put(state->nl80211); + nl_cache_free(state->nl_cache); + nl_socket_free(state->nl_sock); +} + +static int +add_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state, + const char *device, const char *mondevice) +{ + int ifindex; + struct nl_msg *msg; + int err; + + ifindex = iface_get_id(sock_fd, device, handle->errbuf); + if (ifindex == -1) + return PCAP_ERROR; + + msg = nlmsg_alloc(); + if (!msg) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: failed to allocate netlink msg", device); + return PCAP_ERROR; + } + + genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, + 0, NL80211_CMD_NEW_INTERFACE, 0); + NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); + NLA_PUT_STRING(msg, NL80211_ATTR_IFNAME, mondevice); + NLA_PUT_U32(msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_MONITOR); + + err = nl_send_auto_complete(state->nl_sock, msg); + if (err < 0) { +#ifdef HAVE_LIBNL_2_x + if (err == -NLE_FAILURE) { +#else + if (err == -ENFILE) { +#endif + /* + * Device not available; our caller should just + * keep trying. (libnl 2.x maps ENFILE to + * NLE_FAILURE; it can also map other errors + * to that, but there's not much we can do + * about that.) + */ + nlmsg_free(msg); + return 0; + } else { + /* + * Real failure, not just "that device is not + * available. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_send_auto_complete failed adding %s interface: %s", + device, mondevice, get_nl_errmsg(-err)); + nlmsg_free(msg); + return PCAP_ERROR; + } + } + err = nl_wait_for_ack(state->nl_sock); + if (err < 0) { +#ifdef HAVE_LIBNL_2_x + if (err == -NLE_FAILURE) { +#else + if (err == -ENFILE) { +#endif + /* + * Device not available; our caller should just + * keep trying. (libnl 2.x maps ENFILE to + * NLE_FAILURE; it can also map other errors + * to that, but there's not much we can do + * about that.) + */ + nlmsg_free(msg); + return 0; + } else { + /* + * Real failure, not just "that device is not + * available. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_wait_for_ack failed adding %s interface: %s", + device, mondevice, get_nl_errmsg(-err)); + nlmsg_free(msg); + return PCAP_ERROR; + } + } + + /* + * Success. + */ + nlmsg_free(msg); + return 1; + +nla_put_failure: + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_put failed adding %s interface", + device, mondevice); + nlmsg_free(msg); + return PCAP_ERROR; +} + +static int +del_mon_if(pcap_t *handle, int sock_fd, struct nl80211_state *state, + const char *device, const char *mondevice) +{ + int ifindex; + struct nl_msg *msg; + int err; + + ifindex = iface_get_id(sock_fd, mondevice, handle->errbuf); + if (ifindex == -1) + return PCAP_ERROR; + + msg = nlmsg_alloc(); + if (!msg) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: failed to allocate netlink msg", device); + return PCAP_ERROR; + } + + genlmsg_put(msg, 0, 0, genl_family_get_id(state->nl80211), 0, + 0, NL80211_CMD_DEL_INTERFACE, 0); + NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, ifindex); + + err = nl_send_auto_complete(state->nl_sock, msg); + if (err < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_send_auto_complete failed deleting %s interface: %s", + device, mondevice, get_nl_errmsg(-err)); + nlmsg_free(msg); + return PCAP_ERROR; + } + err = nl_wait_for_ack(state->nl_sock); + if (err < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_wait_for_ack failed adding %s interface: %s", + device, mondevice, get_nl_errmsg(-err)); + nlmsg_free(msg); + return PCAP_ERROR; + } + + /* + * Success. + */ + nlmsg_free(msg); + return 1; + +nla_put_failure: + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: nl_put failed deleting %s interface", + device, mondevice); + nlmsg_free(msg); + return PCAP_ERROR; +} + +static int +enter_rfmon_mode_mac80211(pcap_t *handle, int sock_fd, const char *device) +{ + int ret; + char phydev_path[PATH_MAX+1]; + struct nl80211_state nlstate; + struct ifreq ifr; + u_int n; + + /* + * Is this a mac80211 device? + */ + ret = get_mac80211_phydev(handle, device, phydev_path, PATH_MAX); + if (ret < 0) + return ret; /* error */ + if (ret == 0) + return 0; /* no error, but not mac80211 device */ + + /* + * XXX - is this already a monN device? + * If so, we're done. + * Is that determined by old Wireless Extensions ioctls? + */ + + /* + * OK, it's apparently a mac80211 device. + * Try to find an unused monN device for it. + */ + ret = nl80211_init(handle, &nlstate, device); + if (ret != 0) + return ret; + for (n = 0; n < UINT_MAX; n++) { + /* + * Try mon{n}. + */ + char mondevice[3+10+1]; /* mon{UINT_MAX}\0 */ + + snprintf(mondevice, sizeof mondevice, "mon%u", n); + ret = add_mon_if(handle, sock_fd, &nlstate, device, mondevice); + if (ret == 1) { + handle->md.mondevice = strdup(mondevice); + goto added; + } + if (ret < 0) { + /* + * Hard failure. Just return ret; handle->errbuf + * has already been set. + */ + nl80211_cleanup(&nlstate); + return ret; + } + } + + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: No free monN interfaces", device); + nl80211_cleanup(&nlstate); + return PCAP_ERROR; + +added: + +#if 0 + /* + * Sleep for .1 seconds. + */ + delay.tv_sec = 0; + delay.tv_nsec = 500000000; + nanosleep(&delay, NULL); +#endif + + /* + * If we haven't already done so, arrange to have + * "pcap_close_all()" called when we exit. + */ + if (!pcap_do_addexit(handle)) { + /* + * "atexit()" failed; don't put the interface + * in rfmon mode, just give up. + */ + return PCAP_ERROR_RFMON_NOTSUP; + } + + /* + * Now configure the monitor interface up. + */ + memset(&ifr, 0, sizeof(ifr)); + strncpy(ifr.ifr_name, handle->md.mondevice, sizeof(ifr.ifr_name)); + if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't get flags for %s: %s", device, + handle->md.mondevice, strerror(errno)); + del_mon_if(handle, sock_fd, &nlstate, device, + handle->md.mondevice); + nl80211_cleanup(&nlstate); + return PCAP_ERROR; + } + ifr.ifr_flags |= IFF_UP|IFF_RUNNING; + if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't set flags for %s: %s", device, + handle->md.mondevice, strerror(errno)); + del_mon_if(handle, sock_fd, &nlstate, device, + handle->md.mondevice); + nl80211_cleanup(&nlstate); + return PCAP_ERROR; + } + + /* + * Success. Clean up the libnl state. + */ + nl80211_cleanup(&nlstate); + + /* + * Note that we have to delete the monitor device when we close + * the handle. + */ + handle->md.must_do_on_close |= MUST_DELETE_MONIF; + + /* + * Add this to the list of pcaps to close when we exit. + */ + pcap_add_to_pcaps_to_close(handle); + + return 1; +} +#endif /* HAVE_LIBNL */ + +static int +pcap_can_set_rfmon_linux(pcap_t *handle) +{ +#ifdef HAVE_LIBNL + char phydev_path[PATH_MAX+1]; + int ret; +#endif #ifdef IW_MODE_MONITOR int sock_fd; struct iwreq ireq; #endif - if (p->opt.source == NULL) { + if (strcmp(handle->opt.source, "any") == 0) { /* - * This is equivalent to the "any" device, and we don't - * support monitor mode on it. + * Monitor mode makes no sense on the "any" device. */ return 0; } +#ifdef HAVE_LIBNL + /* + * Bleah. There doesn't seem to be a way to ask a mac80211 + * device, through libnl, whether it supports monitor mode; + * we'll just check whether the device appears to be a + * mac80211 device and, if so, assume the device supports + * monitor mode. + * + * wmaster devices don't appear to support the Wireless + * Extensions, but we can create a mon device for a + * wmaster device, so we don't bother checking whether + * a mac80211 device supports the Wireless Extensions. + */ + ret = get_mac80211_phydev(handle, handle->opt.source, phydev_path, + PATH_MAX); + if (ret < 0) + return ret; /* error */ + if (ret == 1) + return 1; /* mac80211 device */ +#endif + #ifdef IW_MODE_MONITOR /* * Bleah. There doesn't appear to be an ioctl to use to ask @@ -343,7 +984,7 @@ pcap_can_set_rfmon_linux(pcap_t *p) */ sock_fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); if (sock_fd == -1) { - (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, + (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); return PCAP_ERROR; } @@ -351,7 +992,7 @@ pcap_can_set_rfmon_linux(pcap_t *p) /* * Attempt to get the current mode. */ - strncpy(ireq.ifr_ifrn.ifrn_name, p->opt.source, + strncpy(ireq.ifr_ifrn.ifrn_name, handle->opt.source, sizeof ireq.ifr_ifrn.ifrn_name); ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; if (ioctl(sock_fd, SIOCGIWMODE, &ireq) != -1) { @@ -363,6 +1004,8 @@ pcap_can_set_rfmon_linux(pcap_t *p) } if (errno == ENODEV) { /* The device doesn't even exist. */ + (void)snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "SIOCGIWMODE failed: %s", pcap_strerror(errno)); close(sock_fd); return PCAP_ERROR_NO_SUCH_DEVICE; } @@ -371,6 +1014,67 @@ pcap_can_set_rfmon_linux(pcap_t *p) return 0; } +/* + * Grabs the number of dropped packets by the interface from /proc/net/dev. + * + * XXX - what about /sys/class/net/{interface name}/rx_*? There are + * individual devices giving, in ASCII, various rx_ and tx_ statistics. + * + * Or can we get them in binary form from netlink? + */ +static long int +linux_if_drops(const char * if_name) +{ + char buffer[512]; + char * bufptr; + FILE * file; + int field_to_convert = 3, if_name_sz = strlen(if_name); + long int dropped_pkts = 0; + + file = fopen("/proc/net/dev", "r"); + if (!file) + return 0; + + while (!dropped_pkts && fgets( buffer, sizeof(buffer), file )) + { + /* search for 'bytes' -- if its in there, then + that means we need to grab the fourth field. otherwise + grab the third field. */ + if (field_to_convert != 4 && strstr(buffer, "bytes")) + { + field_to_convert = 4; + continue; + } + + /* find iface and make sure it actually matches -- space before the name and : after it */ + if ((bufptr = strstr(buffer, if_name)) && + (bufptr == buffer || *(bufptr-1) == ' ') && + *(bufptr + if_name_sz) == ':') + { + bufptr = bufptr + if_name_sz + 1; + + /* grab the nth field from it */ + while( --field_to_convert && *bufptr != '\0') + { + while (*bufptr != '\0' && *(bufptr++) == ' '); + while (*bufptr != '\0' && *(bufptr++) != ' '); + } + + /* get rid of any final spaces */ + while (*bufptr != '\0' && *bufptr == ' ') bufptr++; + + if (*bufptr != '\0') + dropped_pkts = strtol(bufptr, NULL, 10); + + break; + } + } + + fclose(file); + return dropped_pkts; +} + + /* * With older kernels promiscuous mode is kind of interesting because we * have to reset the interface before exiting. The problem can't really @@ -383,19 +1087,24 @@ pcap_can_set_rfmon_linux(pcap_t *p) * Even with newer kernels, we have the same issue with rfmon mode. */ -static void pcap_close_linux( pcap_t *handle ) +static void pcap_cleanup_linux( pcap_t *handle ) { struct ifreq ifr; +#ifdef HAVE_LIBNL + struct nl80211_state nlstate; + int ret; +#endif /* HAVE_LIBNL */ #ifdef IW_MODE_MONITOR + int oldflags; struct iwreq ireq; -#endif +#endif /* IW_MODE_MONITOR */ - if (handle->md.must_clear != 0) { + if (handle->md.must_do_on_close != 0) { /* * There's something we have to do when closing this * pcap_t. */ - if (handle->md.must_clear & MUST_CLEAR_PROMISC) { + if (handle->md.must_do_on_close & MUST_CLEAR_PROMISC) { /* * We put the interface into promiscuous mode; * take it out of promiscuous mode. @@ -410,10 +1119,10 @@ static void pcap_close_linux( pcap_t *handle ) sizeof(ifr.ifr_name)); if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) == -1) { fprintf(stderr, - "Can't restore interface flags (SIOCGIFFLAGS failed: %s).\n" + "Can't restore interface %s flags (SIOCGIFFLAGS failed: %s).\n" "Please adjust manually.\n" "Hint: This can't happen with Linux >= 2.2.0.\n", - strerror(errno)); + handle->md.device, strerror(errno)); } else { if (ifr.ifr_flags & IFF_PROMISC) { /* @@ -424,17 +1133,35 @@ static void pcap_close_linux( pcap_t *handle ) if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) { fprintf(stderr, - "Can't restore interface flags (SIOCSIFFLAGS failed: %s).\n" + "Can't restore interface %s flags (SIOCSIFFLAGS failed: %s).\n" "Please adjust manually.\n" "Hint: This can't happen with Linux >= 2.2.0.\n", + handle->md.device, strerror(errno)); } } } } +#ifdef HAVE_LIBNL + if (handle->md.must_do_on_close & MUST_DELETE_MONIF) { + ret = nl80211_init(handle, &nlstate, handle->md.device); + if (ret >= 0) { + ret = del_mon_if(handle, handle->fd, &nlstate, + handle->md.device, handle->md.mondevice); + nl80211_cleanup(&nlstate); + } + if (ret < 0) { + fprintf(stderr, + "Can't delete monitor interface %s (%s).\n" + "Please delete manually.\n", + handle->md.mondevice, handle->errbuf); + } + } +#endif /* HAVE_LIBNL */ + #ifdef IW_MODE_MONITOR - if (handle->md.must_clear & MUST_CLEAR_RFMON) { + if (handle->md.must_do_on_close & MUST_CLEAR_RFMON) { /* * We put the interface into rfmon mode; * take it out of rfmon mode. @@ -443,6 +1170,29 @@ static void pcap_close_linux( pcap_t *handle ) * mode, this code cannot know that, so it'll take * it out of rfmon mode. */ + + /* + * First, take the interface down if it's up; + * otherwise, we might get EBUSY. + * If we get errors, just drive on and print + * a warning if we can't restore the mode. + */ + oldflags = 0; + memset(&ifr, 0, sizeof(ifr)); + strncpy(ifr.ifr_name, handle->md.device, + sizeof(ifr.ifr_name)); + if (ioctl(handle->fd, SIOCGIFFLAGS, &ifr) != -1) { + if (ifr.ifr_flags & IFF_UP) { + oldflags = ifr.ifr_flags; + ifr.ifr_flags &= ~IFF_UP; + if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) + oldflags = 0; /* didn't set, don't restore */ + } + } + + /* + * Now restore the mode. + */ strncpy(ireq.ifr_ifrn.ifrn_name, handle->md.device, sizeof ireq.ifr_ifrn.ifrn_name); ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] @@ -453,12 +1203,26 @@ static void pcap_close_linux( pcap_t *handle ) * Scientist, you've failed. */ fprintf(stderr, - "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n" + "Can't restore interface %s wireless mode (SIOCSIWMODE failed: %s).\n" "Please adjust manually.\n", - strerror(errno)); + handle->md.device, strerror(errno)); + } + + /* + * Now bring the interface back up if we brought + * it down. + */ + if (oldflags != 0) { + ifr.ifr_flags = oldflags; + if (ioctl(handle->fd, SIOCSIFFLAGS, &ifr) == -1) { + fprintf(stderr, + "Can't bring interface %s back up (SIOCSIFFLAGS failed: %s).\n" + "Please adjust manually.\n", + handle->md.device, strerror(errno)); + } } } -#endif +#endif /* IW_MODE_MONITOR */ /* * Take this pcap out of the list of pcaps for which we @@ -467,11 +1231,15 @@ static void pcap_close_linux( pcap_t *handle ) pcap_remove_from_pcaps_to_close(handle); } + if (handle->md.mondevice != NULL) { + free(handle->md.mondevice); + handle->md.mondevice = NULL; + } if (handle->md.device != NULL) { free(handle->md.device); handle->md.device = NULL; } - pcap_close_common(handle); + pcap_cleanup_live_common(handle); } /* @@ -486,8 +1254,7 @@ static int pcap_activate_linux(pcap_t *handle) { const char *device; - int err; - int activate_ok = 0; + int status = 0; device = handle->opt.source; @@ -497,32 +1264,39 @@ pcap_activate_linux(pcap_t *handle) handle->set_datalink_op = NULL; /* can't change data link type */ handle->getnonblock_op = pcap_getnonblock_fd; handle->setnonblock_op = pcap_setnonblock_fd; - handle->close_op = pcap_close_linux; + handle->cleanup_op = pcap_cleanup_linux; handle->read_op = pcap_read_linux; handle->stats_op = pcap_stats_linux; /* - * NULL and "any" are special devices which give us the hint to - * monitor all devices. + * The "any" device is a special device which causes us not + * to bind to a particular device and thus to look at all + * devices. */ - if (!device || strcmp(device, "any") == 0) { - device = NULL; - handle->md.device = strdup("any"); + if (strcmp(device, "any") == 0) { if (handle->opt.promisc) { handle->opt.promisc = 0; /* Just a warning. */ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Promiscuous mode not supported on the \"any\" device"); + status = PCAP_WARNING_PROMISC_NOTSUP; } + } - } else - handle->md.device = strdup(device); - + handle->md.device = strdup(device); if (handle->md.device == NULL) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s", pcap_strerror(errno) ); return PCAP_ERROR; } + + /* + * If we're in promiscuous mode, then we probably want + * to see when the interface drops packets too, so get an + * initial count from /proc/net/dev + */ + if (handle->opt.promisc) + handle->md.proc_dropped = linux_if_drops(handle->md.device); /* * Current Linux kernels use the protocol family PF_PACKET to @@ -533,32 +1307,77 @@ pcap_activate_linux(pcap_t *handle) * to be compatible with older kernels for a while so we are * trying both methods with the newer method preferred. */ + status = activate_new(handle); + if (status < 0) { + /* + * Fatal error with the new way; just fail. + * status has the error return; if it's PCAP_ERROR, + * handle->errbuf has been set appropriately. + */ + goto fail; + } + if (status == 1) { + /* + * Success. + * Try to use memory-mapped access. + */ + switch (activate_mmap(handle, &status)) { + + case 1: + /* + * We succeeded. status has been + * set to the status to return, + * which might be 0, or might be + * a PCAP_WARNING_ value. + */ + return status; + + case 0: + /* + * Kernel doesn't support it - just continue + * with non-memory-mapped access. + */ + break; - if ((err = activate_new(handle)) == 1) { - activate_ok = 1; - /* - * Try to use memory-mapped access. - */ - if (activate_mmap(handle) == 1) - return 0; /* we succeeded; nothing more to do */ + case -1: + /* + * We failed to set up to use it, or the kernel + * supports it, but we failed to enable it. + * status has been set to the error status to + * return and, if it's PCAP_ERROR, handle->errbuf + * contains the error message. + */ + goto fail; + } } - else if (err == 0) { + else if (status == 0) { /* Non-fatal error; try old way */ - if ((err = activate_old(handle)) == 1) - activate_ok = 1; + if ((status = activate_old(handle)) != 1) { + /* + * Both methods to open the packet socket failed. + * Tidy up and report our failure (handle->errbuf + * is expected to be set by the functions above). + */ + goto fail; + } } - if (!activate_ok) { + + /* + * We set up the socket, but not with memory-mapped access. + */ + status = 0; + if (handle->opt.buffer_size != 0) { /* - * Both methods to open the packet socket failed. Tidy - * up and report our failure (ebuf is expected to be - * set by the functions above). + * Set the socket buffer size to the specified value. */ - - if (handle->md.device != NULL) { - free(handle->md.device); - handle->md.device = NULL; + if (setsockopt(handle->fd, SOL_SOCKET, SO_RCVBUF, + &handle->opt.buffer_size, + sizeof(handle->opt.buffer_size)) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "SO_RCVBUF: %s", pcap_strerror(errno)); + status = PCAP_ERROR; + goto fail; } - return err; } /* Allocate the buffer */ @@ -567,7 +1386,8 @@ pcap_activate_linux(pcap_t *handle) if (!handle->buffer) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); - return PCAP_ERROR; + status = PCAP_ERROR; + goto fail; } /* @@ -576,7 +1396,11 @@ pcap_activate_linux(pcap_t *handle) */ handle->selectable_fd = handle->fd; - return 0; + return status; + +fail: + pcap_cleanup_linux(handle); + return status; } /* @@ -610,7 +1434,17 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) #else struct sockaddr from; #endif +#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) + struct iovec iov; + struct msghdr msg; + struct cmsghdr *cmsg; + union { + struct cmsghdr cmsg; + char buf[CMSG_SPACE(sizeof(struct tpacket_auxdata))]; + } cmsg_buf; +#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ socklen_t fromlen; +#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ int packet_len, caplen; struct pcap_pkthdr pcap_header; @@ -631,38 +1465,85 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) offset = 0; #endif - /* Receive a single packet from the kernel */ - + /* + * Receive a single packet from the kernel. + * We ignore EINTR, as that might just be due to a signal + * being delivered - if the signal should interrupt the + * loop, the signal handler should call pcap_breakloop() + * to set handle->break_loop (we ignore it on other + * platforms as well). + * We also ignore ENETDOWN, so that we can continue to + * capture traffic if the interface goes down and comes + * back up again; comments in the kernel indicate that + * we'll just block waiting for packets if we try to + * receive from a socket that delivered ENETDOWN, and, + * if we're using a memory-mapped buffer, we won't even + * get notified of "network down" events. + */ bp = handle->buffer + handle->offset; + +#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) + msg.msg_name = &from; + msg.msg_namelen = sizeof(from); + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = &cmsg_buf; + msg.msg_controllen = sizeof(cmsg_buf); + msg.msg_flags = 0; + + iov.iov_len = handle->bufsize - offset; + iov.iov_base = bp + offset; +#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ + do { /* * Has "pcap_breakloop()" been called? */ if (handle->break_loop) { /* - * Yes - clear the flag that indicates that it - * has, and return -2 as an indication that we - * were told to break out of the loop. + * Yes - clear the flag that indicates that it has, + * and return PCAP_ERROR_BREAK as an indication that + * we were told to break out of the loop. */ handle->break_loop = 0; - return -2; + return PCAP_ERROR_BREAK; } + +#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) + packet_len = recvmsg(handle->fd, &msg, MSG_TRUNC); +#else /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ fromlen = sizeof(from); packet_len = recvfrom( handle->fd, bp + offset, handle->bufsize - offset, MSG_TRUNC, (struct sockaddr *) &from, &fromlen); +#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ } while (packet_len == -1 && errno == EINTR); /* Check if an error occured */ if (packet_len == -1) { - if (errno == EAGAIN) + switch (errno) { + + case EAGAIN: return 0; /* no packet there */ - else { + + case ENETDOWN: + /* + * The device on which we're capturing went away. + * + * XXX - we should really return + * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch() + * etc. aren't defined to return that. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "The interface went down"); + return PCAP_ERROR; + + default: snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "recvfrom: %s", pcap_strerror(errno)); - return -1; + return PCAP_ERROR; } } @@ -737,7 +1618,45 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) from.sll_halen); hdrp->sll_protocol = from.sll_protocol; } + +#if defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) + if (handle->md.vlan_offset != -1) { + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { + struct tpacket_auxdata *aux; + unsigned int len; + struct vlan_tag *tag; + + if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct tpacket_auxdata)) || + cmsg->cmsg_level != SOL_PACKET || + cmsg->cmsg_type != PACKET_AUXDATA) + continue; + + aux = (struct tpacket_auxdata *)CMSG_DATA(cmsg); +#if defined(TP_STATUS_VLAN_VALID) + if ((aux->tp_vlan_tci == 0) && !(aux->tp_status & TP_STATUS_VLAN_VALID)) +#else + if (aux->tp_vlan_tci == 0) /* this is ambigious but without the + TP_STATUS_VLAN_VALID flag, there is + nothing that we can do */ #endif + continue; + + len = packet_len > iov.iov_len ? iov.iov_len : packet_len; + if (len < (unsigned int) handle->md.vlan_offset) + break; + + bp -= VLAN_TAG_LEN; + memmove(bp, bp + VLAN_TAG_LEN, handle->md.vlan_offset); + + tag = (struct vlan_tag *)(bp + handle->md.vlan_offset); + tag->vlan_tpid = htons(ETH_P_8021Q); + tag->vlan_tci = htons(aux->tp_vlan_tci); + + packet_len += VLAN_TAG_LEN; + } + } +#endif /* defined(HAVE_PACKET_AUXDATA) && defined(HAVE_LINUX_TPACKET_AUXDATA_TP_VLAN_TCI) */ +#endif /* HAVE_PF_PACKET_SOCKETS */ /* * XXX: According to the kernel source we should get the real @@ -790,7 +1709,7 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) if (ioctl(handle->fd, SIOCGSTAMP, &pcap_header.ts) == -1) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "SIOCGSTAMP: %s", pcap_strerror(errno)); - return -1; + return PCAP_ERROR; } pcap_header.caplen = caplen; pcap_header.len = packet_len; @@ -905,6 +1824,18 @@ pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats) socklen_t len = sizeof (struct tpacket_stats); #endif + long if_dropped = 0; + + /* + * To fill in ps_ifdrop, we parse /proc/net/dev for the number + */ + if (handle->opt.promisc) + { + if_dropped = handle->md.proc_dropped; + handle->md.proc_dropped = linux_if_drops(handle->md.device); + handle->md.stat.ps_ifdrop += (handle->md.proc_dropped - if_dropped); + } + #ifdef HAVE_TPACKET_STATS /* * Try to get the packet counts from the kernel. @@ -912,93 +1843,434 @@ pcap_stats_linux(pcap_t *handle, struct pcap_stat *stats) if (getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, &kstats, &len) > -1) { /* - * On systems where the PACKET_STATISTICS "getsockopt()" - * argument is supported on PF_PACKET sockets: - * - * "ps_recv" counts only packets that *passed* the - * filter, not packets that didn't pass the filter. - * This includes packets later dropped because we - * ran out of buffer space. - * - * "ps_drop" counts packets dropped because we ran - * out of buffer space. It doesn't count packets - * dropped by the interface driver. It counts only - * packets that passed the filter. - * - * Both statistics include packets not yet read from - * the kernel by libpcap, and thus not yet seen by - * the application. - * - * In "linux/net/packet/af_packet.c", at least in the - * 2.4.9 kernel, "tp_packets" is incremented for every - * packet that passes the packet filter *and* is - * successfully queued on the socket; "tp_drops" is - * incremented for every packet dropped because there's - * not enough free space in the socket buffer. - * - * When the statistics are returned for a PACKET_STATISTICS - * "getsockopt()" call, "tp_drops" is added to "tp_packets", - * so that "tp_packets" counts all packets handed to - * the PF_PACKET socket, including packets dropped because - * there wasn't room on the socket buffer - but not - * including packets that didn't pass the filter. - * - * In the BSD BPF, the count of received packets is - * incremented for every packet handed to BPF, regardless - * of whether it passed the filter. - * - * We can't make "pcap_stats()" work the same on both - * platforms, but the best approximation is to return - * "tp_packets" as the count of packets and "tp_drops" - * as the count of drops. - * - * Keep a running total because each call to - * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, .... - * resets the counters to zero. + * On systems where the PACKET_STATISTICS "getsockopt()" + * argument is supported on PF_PACKET sockets: + * + * "ps_recv" counts only packets that *passed* the + * filter, not packets that didn't pass the filter. + * This includes packets later dropped because we + * ran out of buffer space. + * + * "ps_drop" counts packets dropped because we ran + * out of buffer space. It doesn't count packets + * dropped by the interface driver. It counts only + * packets that passed the filter. + * + * See above for ps_ifdrop. + * + * Both statistics include packets not yet read from + * the kernel by libpcap, and thus not yet seen by + * the application. + * + * In "linux/net/packet/af_packet.c", at least in the + * 2.4.9 kernel, "tp_packets" is incremented for every + * packet that passes the packet filter *and* is + * successfully queued on the socket; "tp_drops" is + * incremented for every packet dropped because there's + * not enough free space in the socket buffer. + * + * When the statistics are returned for a PACKET_STATISTICS + * "getsockopt()" call, "tp_drops" is added to "tp_packets", + * so that "tp_packets" counts all packets handed to + * the PF_PACKET socket, including packets dropped because + * there wasn't room on the socket buffer - but not + * including packets that didn't pass the filter. + * + * In the BSD BPF, the count of received packets is + * incremented for every packet handed to BPF, regardless + * of whether it passed the filter. + * + * We can't make "pcap_stats()" work the same on both + * platforms, but the best approximation is to return + * "tp_packets" as the count of packets and "tp_drops" + * as the count of drops. + * + * Keep a running total because each call to + * getsockopt(handle->fd, SOL_PACKET, PACKET_STATISTICS, .... + * resets the counters to zero. + */ + handle->md.stat.ps_recv += kstats.tp_packets; + handle->md.stat.ps_drop += kstats.tp_drops; + *stats = handle->md.stat; + return 0; + } + else + { + /* + * If the error was EOPNOTSUPP, fall through, so that + * if you build the library on a system with + * "struct tpacket_stats" and run it on a system + * that doesn't, it works as it does if the library + * is built on a system without "struct tpacket_stats". + */ + if (errno != EOPNOTSUPP) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "pcap_stats: %s", pcap_strerror(errno)); + return -1; + } + } +#endif + /* + * On systems where the PACKET_STATISTICS "getsockopt()" argument + * is not supported on PF_PACKET sockets: + * + * "ps_recv" counts only packets that *passed* the filter, + * not packets that didn't pass the filter. It does not + * count packets dropped because we ran out of buffer + * space. + * + * "ps_drop" is not supported. + * + * "ps_ifdrop" is supported. It will return the number + * of drops the interface reports in /proc/net/dev, + * if that is available. + * + * "ps_recv" doesn't include packets not yet read from + * the kernel by libpcap. + * + * We maintain the count of packets processed by libpcap in + * "md.packets_read", for reasons described in the comment + * at the end of pcap_read_packet(). We have no idea how many + * packets were dropped by the kernel buffers -- but we know + * how many the interface dropped, so we can return that. + */ + + stats->ps_recv = handle->md.packets_read; + stats->ps_drop = 0; + stats->ps_ifdrop = handle->md.stat.ps_ifdrop; + return 0; +} + +/* + * Get from "/sys/class/net" all interfaces listed there; if they're + * already in the list of interfaces we have, that won't add another + * instance, but if they're not, that'll add them. + * + * We don't bother getting any addresses for them; it appears you can't + * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and, + * although some other types of addresses can be fetched with SIOCGIFADDR, + * we don't bother with them for now. + * + * We also don't fail if we couldn't open "/sys/class/net"; we just leave + * the list of interfaces as is, and return 0, so that we can try + * scanning /proc/net/dev. + */ +static int +scan_sys_class_net(pcap_if_t **devlistp, char *errbuf) +{ + DIR *sys_class_net_d; + int fd; + struct dirent *ent; + char subsystem_path[PATH_MAX+1]; + struct stat statb; + char *p; + char name[512]; /* XXX - pick a size */ + char *q, *saveq; + struct ifreq ifrflags; + int ret = 1; + + sys_class_net_d = opendir("/sys/class/net"); + if (sys_class_net_d == NULL) { + /* + * Don't fail if it doesn't exist at all. + */ + if (errno == ENOENT) + return (0); + + /* + * Fail if we got some other error. + */ + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "Can't open /sys/class/net: %s", pcap_strerror(errno)); + return (-1); + } + + /* + * Create a socket from which to fetch interface information. + */ + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) { + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "socket: %s", pcap_strerror(errno)); + (void)closedir(sys_class_net_d); + return (-1); + } + + for (;;) { + errno = 0; + ent = readdir(sys_class_net_d); + if (ent == NULL) { + /* + * Error or EOF; if errno != 0, it's an error. + */ + break; + } + + /* + * Ignore "." and "..". + */ + if (strcmp(ent->d_name, ".") == 0 || + strcmp(ent->d_name, "..") == 0) + continue; + + /* + * Ignore plain files; they do not have subdirectories + * and thus have no attributes. + */ + if (ent->d_type == DT_REG) + continue; + + /* + * Is there an "ifindex" file under that name? + * (We don't care whether it's a directory or + * a symlink; older kernels have directories + * for devices, newer kernels have symlinks to + * directories.) + */ + snprintf(subsystem_path, sizeof subsystem_path, + "/sys/class/net/%s/ifindex", ent->d_name); + if (lstat(subsystem_path, &statb) != 0) { + /* + * Stat failed. Either there was an error + * other than ENOENT, and we don't know if + * this is an interface, or it's ENOENT, + * and either some part of "/sys/class/net/{if}" + * disappeared, in which case it probably means + * the interface disappeared, or there's no + * "ifindex" file, which means it's not a + * network interface. + */ + continue; + } + + /* + * Get the interface name. + */ + p = &ent->d_name[0]; + q = &name[0]; + while (*p != '\0' && isascii(*p) && !isspace(*p)) { + if (*p == ':') { + /* + * This could be the separator between a + * name and an alias number, or it could be + * the separator between a name with no + * alias number and the next field. + * + * If there's a colon after digits, it + * separates the name and the alias number, + * otherwise it separates the name and the + * next field. + */ + saveq = q; + while (isascii(*p) && isdigit(*p)) + *q++ = *p++; + if (*p != ':') { + /* + * That was the next field, + * not the alias number. + */ + q = saveq; + } + break; + } else + *q++ = *p++; + } + *q = '\0'; + + /* + * Get the flags for this interface, and skip it if + * it's not up. + */ + strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); + if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { + if (errno == ENXIO || errno == ENODEV) + continue; + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "SIOCGIFFLAGS: %.*s: %s", + (int)sizeof(ifrflags.ifr_name), + ifrflags.ifr_name, + pcap_strerror(errno)); + ret = -1; + break; + } + if (!(ifrflags.ifr_flags & IFF_UP)) + continue; + + /* + * Add an entry for this interface, with no addresses. + */ + if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, + errbuf) == -1) { + /* + * Failure. + */ + ret = -1; + break; + } + } + if (ret != -1) { + /* + * Well, we didn't fail for any other reason; did we + * fail due to an error reading the directory? + */ + if (errno != 0) { + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "Error reading /sys/class/net: %s", + pcap_strerror(errno)); + ret = -1; + } + } + + (void)close(fd); + (void)closedir(sys_class_net_d); + return (ret); +} + +/* + * Get from "/proc/net/dev" all interfaces listed there; if they're + * already in the list of interfaces we have, that won't add another + * instance, but if they're not, that'll add them. + * + * See comments from scan_sys_class_net(). + */ +static int +scan_proc_net_dev(pcap_if_t **devlistp, char *errbuf) +{ + FILE *proc_net_f; + int fd; + char linebuf[512]; + int linenum; + char *p; + char name[512]; /* XXX - pick a size */ + char *q, *saveq; + struct ifreq ifrflags; + int ret = 0; + + proc_net_f = fopen("/proc/net/dev", "r"); + if (proc_net_f == NULL) { + /* + * Don't fail if it doesn't exist at all. + */ + if (errno == ENOENT) + return (0); + + /* + * Fail if we got some other error. + */ + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "Can't open /proc/net/dev: %s", pcap_strerror(errno)); + return (-1); + } + + /* + * Create a socket from which to fetch interface information. + */ + fd = socket(AF_INET, SOCK_DGRAM, 0); + if (fd < 0) { + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "socket: %s", pcap_strerror(errno)); + (void)fclose(proc_net_f); + return (-1); + } + + for (linenum = 1; + fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) { + /* + * Skip the first two lines - they're headers. + */ + if (linenum <= 2) + continue; + + p = &linebuf[0]; + + /* + * Skip leading white space. + */ + while (*p != '\0' && isascii(*p) && isspace(*p)) + p++; + if (*p == '\0' || *p == '\n') + continue; /* blank line */ + + /* + * Get the interface name. + */ + q = &name[0]; + while (*p != '\0' && isascii(*p) && !isspace(*p)) { + if (*p == ':') { + /* + * This could be the separator between a + * name and an alias number, or it could be + * the separator between a name with no + * alias number and the next field. + * + * If there's a colon after digits, it + * separates the name and the alias number, + * otherwise it separates the name and the + * next field. + */ + saveq = q; + while (isascii(*p) && isdigit(*p)) + *q++ = *p++; + if (*p != ':') { + /* + * That was the next field, + * not the alias number. + */ + q = saveq; + } + break; + } else + *q++ = *p++; + } + *q = '\0'; + + /* + * Get the flags for this interface, and skip it if + * it's not up. + */ + strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); + if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { + if (errno == ENXIO) + continue; + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "SIOCGIFFLAGS: %.*s: %s", + (int)sizeof(ifrflags.ifr_name), + ifrflags.ifr_name, + pcap_strerror(errno)); + ret = -1; + break; + } + if (!(ifrflags.ifr_flags & IFF_UP)) + continue; + + /* + * Add an entry for this interface, with no addresses. */ - handle->md.stat.ps_recv += kstats.tp_packets; - handle->md.stat.ps_drop += kstats.tp_drops; - *stats = handle->md.stat; - return 0; + if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, + errbuf) == -1) { + /* + * Failure. + */ + ret = -1; + break; + } } - else - { + if (ret != -1) { /* - * If the error was EOPNOTSUPP, fall through, so that - * if you build the library on a system with - * "struct tpacket_stats" and run it on a system - * that doesn't, it works as it does if the library - * is built on a system without "struct tpacket_stats". + * Well, we didn't fail for any other reason; did we + * fail due to an error reading the file? */ - if (errno != EOPNOTSUPP) { - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, - "pcap_stats: %s", pcap_strerror(errno)); - return -1; + if (ferror(proc_net_f)) { + (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, + "Error reading /proc/net/dev: %s", + pcap_strerror(errno)); + ret = -1; } } -#endif - /* - * On systems where the PACKET_STATISTICS "getsockopt()" argument - * is not supported on PF_PACKET sockets: - * - * "ps_recv" counts only packets that *passed* the filter, - * not packets that didn't pass the filter. It does not - * count packets dropped because we ran out of buffer - * space. - * - * "ps_drop" is not supported. - * - * "ps_recv" doesn't include packets not yet read from - * the kernel by libpcap. - * - * We maintain the count of packets processed by libpcap in - * "md.packets_read", for reasons described in the comment - * at the end of pcap_read_packet(). We have no idea how many - * packets were dropped. - */ - stats->ps_recv = handle->md.packets_read; - stats->ps_drop = 0; - return 0; + + (void)close(fd); + (void)fclose(proc_net_f); + return (ret); } /* @@ -1009,29 +2281,83 @@ static const char any_descr[] = "Pseudo-device that captures on all interfaces"; int pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) { + int ret; + + /* + * Read "/sys/class/net", and add to the list of interfaces all + * interfaces listed there that we don't already have, because, + * on Linux, SIOCGIFCONF reports only interfaces with IPv4 addresses, + * and even getifaddrs() won't return information about + * interfaces with no addresses, so you need to read "/sys/class/net" + * to get the names of the rest of the interfaces. + */ + ret = scan_sys_class_net(alldevsp, errbuf); + if (ret == -1) + return (-1); /* failed */ + if (ret == 0) { + /* + * No /sys/class/net; try reading /proc/net/dev instead. + */ + if (scan_proc_net_dev(alldevsp, errbuf) == -1) + return (-1); + } + + /* + * Add the "any" device. + */ if (pcap_add_if(alldevsp, "any", 0, any_descr, errbuf) < 0) return (-1); #ifdef HAVE_DAG_API + /* + * Add DAG devices. + */ if (dag_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif /* HAVE_DAG_API */ #ifdef HAVE_SEPTEL_API + /* + * Add Septel devices. + */ if (septel_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif /* HAVE_SEPTEL_API */ +#ifdef HAVE_SNF_API + if (snf_platform_finddevs(alldevsp, errbuf) < 0) + return (-1); +#endif /* HAVE_SNF_API */ + #ifdef PCAP_SUPPORT_BT + /* + * Add Bluetooth devices. + */ if (bt_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif #ifdef PCAP_SUPPORT_USB + /* + * Add USB devices. + */ if (usb_platform_finddevs(alldevsp, errbuf) < 0) return (-1); #endif +#ifdef PCAP_SUPPORT_NETFILTER + /* + * Add netfilter devices. + */ + if (netfilter_platform_finddevs(alldevsp, errbuf) < 0) + return (-1); +#endif + +#if PCAP_SUPPORT_CANUSB + if (canusb_platform_finddevs(alldevsp, errbuf) < 0) + return (-1); +#endif + return (0); } @@ -1039,7 +2365,8 @@ pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) * Attach the given BPF code to the packet capture device. */ static int -pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) +pcap_setfilter_linux_common(pcap_t *handle, struct bpf_program *filter, + int is_mmapped) { #ifdef SO_ATTACH_FILTER struct sock_fprog fcode; @@ -1092,13 +2419,13 @@ pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) * * Oh, and we also need to fix it up so that all "ret" * instructions with non-zero operands have 65535 as the - * operand, and so that, if we're in cooked mode, all - * memory-reference instructions use special magic offsets - * in references to the link-layer header and assume that - * the link-layer payload begins at 0; "fix_program()" - * will do that. + * operand if we're not capturing in memory-mapped modee, + * and so that, if we're in cooked mode, all memory-reference + * instructions use special magic offsets in references to + * the link-layer header and assume that the link-layer + * payload begins at 0; "fix_program()" will do that. */ - switch (fix_program(handle, &fcode)) { + switch (fix_program(handle, &fcode, is_mmapped)) { case -1: default: @@ -1126,6 +2453,30 @@ pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) } } + /* + * NOTE: at this point, we've set both the "len" and "filter" + * fields of "fcode". As of the 2.6.32.4 kernel, at least, + * those are the only members of the "sock_fprog" structure, + * so we initialize every member of that structure. + * + * If there is anything in "fcode" that is not initialized, + * it is either a field added in a later kernel, or it's + * padding. + * + * If a new field is added, this code needs to be updated + * to set it correctly. + * + * If there are no other fields, then: + * + * if the Linux kernel looks at the padding, it's + * buggy; + * + * if the Linux kernel doesn't look at the padding, + * then if some tool complains that we're passing + * uninitialized data to the kernel, then the tool + * is buggy and needs to understand that it's just + * padding. + */ if (can_filter_in_kernel) { if ((err = set_kernel_filter(handle, &fcode)) == 0) { @@ -1172,6 +2523,13 @@ pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) return 0; } +static int +pcap_setfilter_linux(pcap_t *handle, struct bpf_program *filter) +{ + return pcap_setfilter_linux_common(handle, filter, 0); +} + + /* * Set direction flag: Which packets do we accept on a forwarding * single device? IN, OUT or both? @@ -1194,7 +2552,6 @@ pcap_setdirection_linux(pcap_t *handle, pcap_direction_t d) return -1; } - #ifdef HAVE_PF_PACKET_SOCKETS /* * Map the PACKET_ value to a LINUX_SLL_ value; we @@ -1230,6 +2587,51 @@ map_packet_type_to_sll_type(short int sll_pkttype) } #endif +static int +is_wifi(int sock_fd +#ifndef IW_MODE_MONITOR +_U_ +#endif +, const char *device) +{ + char *pathstr; + struct stat statb; +#ifdef IW_MODE_MONITOR + char errbuf[PCAP_ERRBUF_SIZE]; +#endif + + /* + * See if there's a sysfs wireless directory for it. + * If so, it's a wireless interface. + */ + if (asprintf(&pathstr, "/sys/class/net/%s/wireless", device) == -1) { + /* + * Just give up here. + */ + return 0; + } + if (stat(pathstr, &statb) == 0) { + free(pathstr); + return 1; + } + free(pathstr); + +#ifdef IW_MODE_MONITOR + /* + * OK, maybe it's not wireless, or maybe this kernel doesn't + * support sysfs. Try the wireless extensions. + */ + if (has_wext(sock_fd, device, errbuf) == 1) { + /* + * It supports the wireless extensions, so it's a Wi-Fi + * device. + */ + return 1; + } +#endif + return 0; +} + /* * Linux uses the ARP hardware type to identify the type of an * interface. pcap uses the DLT_xxx constants for this. This @@ -1248,13 +2650,33 @@ map_packet_type_to_sll_type(short int sll_pkttype) * * Sets the link type to -1 if unable to map the type. */ -static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) +static void map_arphrd_to_dlt(pcap_t *handle, int sock_fd, int arptype, + const char *device, int cooked_ok) { + static const char cdma_rmnet[] = "cdma_rmnet"; + switch (arptype) { case ARPHRD_ETHER: /* - * This is (presumably) a real Ethernet capture; give it a + * For various annoying reasons having to do with DHCP + * software, some versions of Android give the mobile- + * phone-network interface an ARPHRD_ value of + * ARPHRD_ETHER, even though the packets supplied by + * that interface have no link-layer header, and begin + * with an IP header, so that the ARPHRD_ value should + * be ARPHRD_NONE. + * + * Detect those devices by checking the device name, and + * use DLT_RAW for them. + */ + if (strncmp(device, cdma_rmnet, sizeof cdma_rmnet - 1) == 0) { + handle->linktype = DLT_RAW; + return; + } + + /* + * Is this a real Ethernet device? If so, give it a * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so * that an application can let you choose it, in case you're * capturing DOCSIS traffic that a Cisco Cable Modem @@ -1263,21 +2685,27 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) * DOCSIS frames out on the wire inside the low-level * Ethernet framing). * - * XXX - are there any sorts of "fake Ethernet" that have - * ARPHRD_ETHER but that *shouldn't offer DLT_DOCSIS as + * XXX - are there any other sorts of "fake Ethernet" that + * have ARPHRD_ETHER but that shouldn't offer DLT_DOCSIS as * a Cisco CMTS won't put traffic onto it or get traffic * bridged onto it? ISDN is handled in "activate_new()", - * as we fall back on cooked mode there; are there any + * as we fall back on cooked mode there, and we use + * is_wifi() to check for 802.11 devices; are there any * others? */ - handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); - /* - * If that fails, just leave the list empty. - */ - if (handle->dlt_list != NULL) { - handle->dlt_list[0] = DLT_EN10MB; - handle->dlt_list[1] = DLT_DOCSIS; - handle->dlt_count = 2; + if (!is_wifi(sock_fd, device)) { + /* + * It's not a Wi-Fi device; offer DOCSIS. + */ + handle->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); + /* + * If that fails, just leave the list empty. + */ + if (handle->dlt_list != NULL) { + handle->dlt_list[0] = DLT_EN10MB; + handle->dlt_list[1] = DLT_DOCSIS; + handle->dlt_count = 2; + } } /* FALLTHROUGH */ @@ -1302,6 +2730,12 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) case ARPHRD_CHAOS: handle->linktype = DLT_CHAOS; break; +#ifndef ARPHRD_CAN +#define ARPHRD_CAN 280 +#endif + case ARPHRD_CAN: + handle->linktype = DLT_CAN_SOCKETCAN; + break; #ifndef ARPHRD_IEEE802_TR #define ARPHRD_IEEE802_TR 800 /* From Linux 2.4 */ @@ -1524,6 +2958,24 @@ static void map_arphrd_to_dlt(pcap_t *handle, int arptype, int cooked_ok) handle->linktype = DLT_LINUX_LAPD; break; +#ifndef ARPHRD_NONE +#define ARPHRD_NONE 0xFFFE +#endif + case ARPHRD_NONE: + /* + * No link-layer header; packets are just IP + * packets, so use DLT_RAW. + */ + handle->linktype = DLT_RAW; + break; + +#ifndef ARPHRD_IEEE802154 +#define ARPHRD_IEEE802154 804 +#endif + case ARPHRD_IEEE802154: + handle->linktype = DLT_IEEE802_15_4_NOFCS; + break; + default: handle->linktype = -1; break; @@ -1543,24 +2995,48 @@ static int activate_new(pcap_t *handle) { #ifdef HAVE_PF_PACKET_SOCKETS + const char *device = handle->opt.source; + int is_any_device = (strcmp(device, "any") == 0); int sock_fd = -1, arptype; +#ifdef HAVE_PACKET_AUXDATA + int val; +#endif int err = 0; struct packet_mreq mr; - const char* device = handle->opt.source; /* - * Open a socket with protocol family packet. If a device is - * given we try to open it in raw mode otherwise we use - * the cooked interface. + * Open a socket with protocol family packet. If the + * "any" device was specified, we open a SOCK_DGRAM + * socket for the cooked interface, otherwise we first + * try a SOCK_RAW socket for the raw interface. */ - sock_fd = device ? - socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)) - : socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)); + sock_fd = is_any_device ? + socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_ALL)) : + socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); if (sock_fd == -1) { + if (errno == EINVAL || errno == EAFNOSUPPORT) { + /* + * We don't support PF_PACKET/SOCK_whatever + * sockets; try the old mechanism. + */ + return 0; + } + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno) ); - return 0; /* try old mechanism */ + if (errno == EPERM || errno == EACCES) { + /* + * You don't have permission to open the + * socket. + */ + return PCAP_ERROR_PERM_DENIED; + } else { + /* + * Other error. + */ + return PCAP_ERROR; + } } /* It seems the kernel supports the new interface. */ @@ -1590,7 +3066,7 @@ activate_new(pcap_t *handle) * to cooked mode if we have an unknown interface type * or a type we know doesn't work well in raw mode. */ - if (device) { + if (!is_any_device) { /* Assume for now we don't need cooked mode. */ handle->md.cooked = 0; @@ -1601,7 +3077,7 @@ activate_new(pcap_t *handle) * because entering monitor mode could change * the link-layer type. */ - err = enter_rfmon_mode_wext(handle, sock_fd, device); + err = enter_rfmon_mode(handle, sock_fd, device); if (err < 0) { /* Hard failure */ close(sock_fd); @@ -1615,13 +3091,22 @@ activate_new(pcap_t *handle) close(sock_fd); return PCAP_ERROR_RFMON_NOTSUP; } + + /* + * Either monitor mode has been turned on for + * the device, or we've been given a different + * device to open for monitor mode. If we've + * been given a different device, use it. + */ + if (handle->md.mondevice != NULL) + device = handle->md.mondevice; } arptype = iface_get_arptype(sock_fd, device, handle->errbuf); if (arptype < 0) { close(sock_fd); return arptype; } - map_arphrd_to_dlt(handle, arptype, 1); + map_arphrd_to_dlt(handle, sock_fd, arptype, device, 1); if (handle->linktype == -1 || handle->linktype == DLT_LINUX_SLL || handle->linktype == DLT_LINUX_IRDA || @@ -1648,7 +3133,18 @@ activate_new(pcap_t *handle) if (sock_fd == -1) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); - return PCAP_ERROR; + if (errno == EPERM || errno == EACCES) { + /* + * You don't have permission to + * open the socket. + */ + return PCAP_ERROR_PERM_DENIED; + } else { + /* + * Other error. + */ + return PCAP_ERROR; + } } handle->md.cooked = 1; @@ -1696,24 +3192,32 @@ activate_new(pcap_t *handle) } if ((err = iface_bind(sock_fd, handle->md.ifindex, - handle->errbuf)) < 0) { + handle->errbuf)) != 1) { close(sock_fd); - if (err == -2) - return PCAP_ERROR; + if (err < 0) + return err; else return 0; /* try old mechanism */ } } else { /* - * This is cooked mode. + * The "any" device. + */ + if (handle->opt.rfmon) { + /* + * It doesn't support monitor mode. + */ + return PCAP_ERROR_RFMON_NOTSUP; + } + + /* + * It uses cooked mode. */ handle->md.cooked = 1; handle->linktype = DLT_LINUX_SLL; /* * We're not bound to a device. - * XXX - true? Or true only if we're using - * the "any" device? * For now, we're using this as an indication * that we can't transmit; stop doing that only * if we figure out how to transmit in cooked @@ -1738,10 +3242,13 @@ activate_new(pcap_t *handle) /* * Hmm, how can we set promiscuous mode on all interfaces? - * I am not sure if that is possible at all. + * I am not sure if that is possible at all. For now, we + * silently ignore attempts to turn promiscuous mode on + * for the "any" device (so you don't have to explicitly + * disable it in programs such as tcpdump). */ - if (device && handle->opt.promisc) { + if (!is_any_device && handle->opt.promisc) { memset(&mr, 0, sizeof(mr)); mr.mr_ifindex = handle->md.ifindex; mr.mr_type = PACKET_MR_PROMISC; @@ -1754,6 +3261,20 @@ activate_new(pcap_t *handle) } } + /* Enable auxillary data if supported and reserve room for + * reconstructing VLAN headers. */ +#ifdef HAVE_PACKET_AUXDATA + val = 1; + if (setsockopt(sock_fd, SOL_PACKET, PACKET_AUXDATA, &val, + sizeof(val)) == -1 && errno != ENOPROTOOPT) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "setsockopt: %s", pcap_strerror(errno)); + close(sock_fd); + return PCAP_ERROR; + } + handle->offset += VLAN_TAG_LEN; +#endif /* HAVE_PACKET_AUXDATA */ + /* * This is a 2.2[.x] or later kernel (we know that * because we're not using a SOCK_PACKET socket - @@ -1774,8 +3295,26 @@ activate_new(pcap_t *handle) } handle->bufsize = handle->snapshot; + /* + * Set the offset at which to insert VLAN tags. + */ + switch (handle->linktype) { + + case DLT_EN10MB: + handle->md.vlan_offset = 2 * ETH_ALEN; + break; + + case DLT_LINUX_SLL: + handle->md.vlan_offset = 14; + break; + + default: + handle->md.vlan_offset = -1; /* unknown */ + break; + } + /* Save the socket FD in the pcap structure */ - handle->fd = sock_fd; + handle->fd = sock_fd; return 1; #else @@ -1786,114 +3325,468 @@ activate_new(pcap_t *handle) #endif } +#ifdef HAVE_PACKET_RING +/* + * Attempt to activate with memory-mapped access. + * + * On success, returns 1, and sets *status to 0 if there are no warnings + * or to a PCAP_WARNING_ code if there is a warning. + * + * On failure due to lack of support for memory-mapped capture, returns + * 0. + * + * On error, returns -1, and sets *status to the appropriate error code; + * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message. + */ static int -activate_mmap(pcap_t *handle) +activate_mmap(pcap_t *handle, int *status) { -#ifdef HAVE_PACKET_RING int ret; + /* + * Attempt to allocate a buffer to hold the contents of one + * packet, for use by the oneshot callback. + */ + handle->md.oneshot_buffer = malloc(handle->snapshot); + if (handle->md.oneshot_buffer == NULL) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't allocate oneshot buffer: %s", + pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; + } + if (handle->opt.buffer_size == 0) { /* by default request 2M for the ring buffer */ handle->opt.buffer_size = 2*1024*1024; } - ret = create_ring(handle); - if (ret == 0) + ret = prepare_tpacket_socket(handle); + if (ret == -1) { + free(handle->md.oneshot_buffer); + *status = PCAP_ERROR; return ret; + } + ret = create_ring(handle, status); + if (ret == 0) { + /* + * We don't support memory-mapped capture; our caller + * will fall back on reading from the socket. + */ + free(handle->md.oneshot_buffer); + return 0; + } + if (ret == -1) { + /* + * Error attempting to enable memory-mapped capture; + * fail. create_ring() has set *status. + */ + free(handle->md.oneshot_buffer); + return -1; + } - /* override some defaults and inherit the other fields from - * activate_new - * handle->offset is used to get the current position into the rx ring - * handle->cc is used to store the ring size */ + /* + * Success. *status has been set either to 0 if there are no + * warnings or to a PCAP_WARNING_ value if there is a warning. + * + * Override some defaults and inherit the other fields from + * activate_new. + * handle->offset is used to get the current position into the rx ring. + * handle->cc is used to store the ring size. + */ handle->read_op = pcap_read_linux_mmap; - handle->close_op = pcap_close_linux_mmap; + handle->cleanup_op = pcap_cleanup_linux_mmap; handle->setfilter_op = pcap_setfilter_linux_mmap; handle->setnonblock_op = pcap_setnonblock_mmap; handle->getnonblock_op = pcap_getnonblock_mmap; + handle->oneshot_callback = pcap_oneshot_mmap; handle->selectable_fd = handle->fd; return 1; +} #else /* HAVE_PACKET_RING */ +static int +activate_mmap(pcap_t *handle _U_, int *status _U_) +{ return 0; -#endif /* HAVE_PACKET_RING */ } +#endif /* HAVE_PACKET_RING */ #ifdef HAVE_PACKET_RING - -static void -compute_ring_block(int frame_size, unsigned *block_size, unsigned *frames_per_block) +/* + * Attempt to set the socket to version 2 of the memory-mapped header. + * Return 1 if we succeed or if we fail because version 2 isn't + * supported; return -1 on any other error, and set handle->errbuf. + */ +static int +prepare_tpacket_socket(pcap_t *handle) { - /* compute the minumum block size that will handle this frame. - * The block has to be page size aligned. - * The max block size allowed by the kernel is arch-dependent and - * it's not explicitly checked here. */ - *block_size = getpagesize(); - while (*block_size < frame_size) - *block_size <<= 1; +#ifdef HAVE_TPACKET2 + socklen_t len; + int val; +#endif + + handle->md.tp_version = TPACKET_V1; + handle->md.tp_hdrlen = sizeof(struct tpacket_hdr); + +#ifdef HAVE_TPACKET2 + /* Probe whether kernel supports TPACKET_V2 */ + val = TPACKET_V2; + len = sizeof(val); + if (getsockopt(handle->fd, SOL_PACKET, PACKET_HDRLEN, &val, &len) < 0) { + if (errno == ENOPROTOOPT) + return 1; /* no - just drive on */ + + /* Yes - treat as a failure. */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't get TPACKET_V2 header len on packet socket: %s", + pcap_strerror(errno)); + return -1; + } + handle->md.tp_hdrlen = val; + + val = TPACKET_V2; + if (setsockopt(handle->fd, SOL_PACKET, PACKET_VERSION, &val, + sizeof(val)) < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't activate TPACKET_V2 on packet socket: %s", + pcap_strerror(errno)); + return -1; + } + handle->md.tp_version = TPACKET_V2; + + /* Reserve space for VLAN tag reconstruction */ + val = VLAN_TAG_LEN; + if (setsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &val, + sizeof(val)) < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't set up reserve on packet socket: %s", + pcap_strerror(errno)); + return -1; + } - *frames_per_block = *block_size/frame_size; +#endif /* HAVE_TPACKET2 */ + return 1; } +/* + * Attempt to set up memory-mapped access. + * + * On success, returns 1, and sets *status to 0 if there are no warnings + * or to a PCAP_WARNING_ code if there is a warning. + * + * On failure due to lack of support for memory-mapped capture, returns + * 0. + * + * On error, returns -1, and sets *status to the appropriate error code; + * if that is PCAP_ERROR, sets handle->errbuf to the appropriate message. + */ static int -create_ring(pcap_t *handle) +create_ring(pcap_t *handle, int *status) { - unsigned i, j, ringsize, frames_per_block; + unsigned i, j, frames_per_block; struct tpacket_req req; + socklen_t len; + unsigned int sk_type, tp_reserve, maclen, tp_hdrlen, netoff, macoff; + unsigned int frame_size; - /* Note that with large snapshot (say 64K) only a few frames - * will be available in the ring even with pretty large ring size - * (and a lot of memory will be unused). - * The snap len should be carefully chosen to achive best - * performance */ - req.tp_frame_size = TPACKET_ALIGN(handle->snapshot+TPACKET_HDRLEN); + /* + * Start out assuming no warnings or errors. + */ + *status = 0; + + /* Note that with large snapshot length (say 64K, which is the default + * for recent versions of tcpdump, the value that "-s 0" has given + * for a long time with tcpdump, and the default in Wireshark/TShark), + * if we use the snapshot length to calculate the frame length, + * only a few frames will be available in the ring even with pretty + * large ring size (and a lot of memory will be unused). + * + * Ideally, we should choose a frame length based on the + * minimum of the specified snapshot length and the maximum + * packet size. That's not as easy as it sounds; consider, for + * example, an 802.11 interface in monitor mode, where the + * frame would include a radiotap header, where the maximum + * radiotap header length is device-dependent. + * + * So, for now, we just do this for Ethernet devices, where + * there's no metadata header, and the link-layer header is + * fixed length. We can get the maximum packet size by + * adding 18, the Ethernet header length plus the CRC length + * (just in case we happen to get the CRC in the packet), to + * the MTU of the interface; we fetch the MTU in the hopes + * that it reflects support for jumbo frames. (Even if the + * interface is just being used for passive snooping, the driver + * might set the size of buffers in the receive ring based on + * the MTU, so that the MTU limits the maximum size of packets + * that we can receive.) + * + * We don't do that if segmentation/fragmentation or receive + * offload are enabled, so we don't get rudely surprised by + * "packets" bigger than the MTU. */ + frame_size = handle->snapshot; + if (handle->linktype == DLT_EN10MB) { + int mtu; + int offload; + + offload = iface_get_offload(handle); + if (offload == -1) { + *status = PCAP_ERROR; + return -1; + } + if (!offload) { + mtu = iface_get_mtu(handle->fd, handle->opt.source, + handle->errbuf); + if (mtu == -1) { + *status = PCAP_ERROR; + return -1; + } + if (frame_size > mtu + 18) + frame_size = mtu + 18; + } + } + + /* NOTE: calculus matching those in tpacket_rcv() + * in linux-2.6/net/packet/af_packet.c + */ + len = sizeof(sk_type); + if (getsockopt(handle->fd, SOL_SOCKET, SO_TYPE, &sk_type, &len) < 0) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "getsockopt: %s", pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; + } +#ifdef PACKET_RESERVE + len = sizeof(tp_reserve); + if (getsockopt(handle->fd, SOL_PACKET, PACKET_RESERVE, &tp_reserve, &len) < 0) { + if (errno != ENOPROTOOPT) { + /* + * ENOPROTOOPT means "kernel doesn't support + * PACKET_RESERVE", in which case we fall back + * as best we can. + */ + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "getsockopt: %s", pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; + } + tp_reserve = 0; /* older kernel, reserve not supported */ + } +#else + tp_reserve = 0; /* older kernel, reserve not supported */ +#endif + maclen = (sk_type == SOCK_DGRAM) ? 0 : MAX_LINKHEADER_SIZE; + /* XXX: in the kernel maclen is calculated from + * LL_ALLOCATED_SPACE(dev) and vnet_hdr.hdr_len + * in: packet_snd() in linux-2.6/net/packet/af_packet.c + * then packet_alloc_skb() in linux-2.6/net/packet/af_packet.c + * then sock_alloc_send_pskb() in linux-2.6/net/core/sock.c + * but I see no way to get those sizes in userspace, + * like for instance with an ifreq ioctl(); + * the best thing I've found so far is MAX_HEADER in the kernel + * part of linux-2.6/include/linux/netdevice.h + * which goes up to 128+48=176; since pcap-linux.c defines + * a MAX_LINKHEADER_SIZE of 256 which is greater than that, + * let's use it.. maybe is it even large enough to directly + * replace macoff.. + */ + tp_hdrlen = TPACKET_ALIGN(handle->md.tp_hdrlen) + sizeof(struct sockaddr_ll) ; + netoff = TPACKET_ALIGN(tp_hdrlen + (maclen < 16 ? 16 : maclen)) + tp_reserve; + /* NOTE: AFAICS tp_reserve may break the TPACKET_ALIGN of + * netoff, which contradicts + * linux-2.6/Documentation/networking/packet_mmap.txt + * documenting that: + * "- Gap, chosen so that packet data (Start+tp_net) + * aligns to TPACKET_ALIGNMENT=16" + */ + /* NOTE: in linux-2.6/include/linux/skbuff.h: + * "CPUs often take a performance hit + * when accessing unaligned memory locations" + */ + macoff = netoff - maclen; + req.tp_frame_size = TPACKET_ALIGN(macoff + frame_size); req.tp_frame_nr = handle->opt.buffer_size/req.tp_frame_size; - compute_ring_block(req.tp_frame_size, &req.tp_block_size, &frames_per_block); - req.tp_block_nr = req.tp_frame_nr / frames_per_block; - /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */ - req.tp_frame_nr = req.tp_block_nr * frames_per_block; + /* compute the minumum block size that will handle this frame. + * The block has to be page size aligned. + * The max block size allowed by the kernel is arch-dependent and + * it's not explicitly checked here. */ + req.tp_block_size = getpagesize(); + while (req.tp_block_size < req.tp_frame_size) + req.tp_block_size <<= 1; + + frames_per_block = req.tp_block_size/req.tp_frame_size; + + /* + * PACKET_TIMESTAMP was added after linux/net_tstamp.h was, + * so we check for PACKET_TIMESTAMP. We check for + * linux/net_tstamp.h just in case a system somehow has + * PACKET_TIMESTAMP but not linux/net_tstamp.h; that might + * be unnecessary. + * + * SIOCSHWTSTAMP was introduced in the patch that introduced + * linux/net_tstamp.h, so we don't bother checking whether + * SIOCSHWTSTAMP is defined (if your Linux system has + * linux/net_tstamp.h but doesn't define SIOCSHWTSTAMP, your + * Linux system is badly broken). + */ +#if defined(HAVE_LINUX_NET_TSTAMP_H) && defined(PACKET_TIMESTAMP) + /* + * If we were told to do so, ask the kernel and the driver + * to use hardware timestamps. + * + * Hardware timestamps are only supported with mmapped + * captures. + */ + if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER || + handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER_UNSYNCED) { + struct hwtstamp_config hwconfig; + struct ifreq ifr; + int timesource; + + /* + * Ask for hardware time stamps on all packets, + * including transmitted packets. + */ + memset(&hwconfig, 0, sizeof(hwconfig)); + hwconfig.tx_type = HWTSTAMP_TX_ON; + hwconfig.rx_filter = HWTSTAMP_FILTER_ALL; + + memset(&ifr, 0, sizeof(ifr)); + strcpy(ifr.ifr_name, handle->opt.source); + ifr.ifr_data = (void *)&hwconfig; + + if (ioctl(handle->fd, SIOCSHWTSTAMP, &ifr) < 0) { + switch (errno) { + + case EPERM: + /* + * Treat this as an error, as the + * user should try to run this + * with the appropriate privileges - + * and, if they can't, shouldn't + * try requesting hardware time stamps. + */ + *status = PCAP_ERROR_PERM_DENIED; + return -1; + + case EOPNOTSUPP: + /* + * Treat this as a warning, as the + * only way to fix the warning is to + * get an adapter that supports hardware + * time stamps. We'll just fall back + * on the standard host time stamps. + */ + *status = PCAP_WARNING_TSTAMP_TYPE_NOTSUP; + break; + + default: + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "SIOCSHWTSTAMP failed: %s", + pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; + } + } else { + /* + * Well, that worked. Now specify the type of + * hardware time stamp we want for this + * socket. + */ + if (handle->opt.tstamp_type == PCAP_TSTAMP_ADAPTER) { + /* + * Hardware timestamp, synchronized + * with the system clock. + */ + timesource = SOF_TIMESTAMPING_SYS_HARDWARE; + } else { + /* + * PCAP_TSTAMP_ADAPTER_UNSYNCED - hardware + * timestamp, not synchronized with the + * system clock. + */ + timesource = SOF_TIMESTAMPING_RAW_HARDWARE; + } + if (setsockopt(handle->fd, SOL_PACKET, PACKET_TIMESTAMP, + (void *)×ource, sizeof(timesource))) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't set PACKET_TIMESTAMP: %s", + pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; + } + } + } +#endif /* HAVE_LINUX_NET_TSTAMP_H && PACKET_TIMESTAMP */ /* ask the kernel to create the ring */ retry: + req.tp_block_nr = req.tp_frame_nr / frames_per_block; + + /* req.tp_frame_nr is requested to match frames_per_block*req.tp_block_nr */ + req.tp_frame_nr = req.tp_block_nr * frames_per_block; + if (setsockopt(handle->fd, SOL_PACKET, PACKET_RX_RING, (void *) &req, sizeof(req))) { - /* try to reduce requested ring size to prevent memory failure */ if ((errno == ENOMEM) && (req.tp_block_nr > 1)) { - req.tp_frame_nr >>= 1; - req.tp_block_nr = req.tp_frame_nr/frames_per_block; + /* + * Memory failure; try to reduce the requested ring + * size. + * + * We used to reduce this by half -- do 5% instead. + * That may result in more iterations and a longer + * startup, but the user will be much happier with + * the resulting buffer size. + */ + if (req.tp_frame_nr < 20) + req.tp_frame_nr -= 1; + else + req.tp_frame_nr -= req.tp_frame_nr/20; goto retry; } - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't create rx ring on " - "packet socket %d: %d-%s", handle->fd, errno, - pcap_strerror(errno)); - return 0; + if (errno == ENOPROTOOPT) { + /* + * We don't have ring buffer support in this kernel. + */ + return 0; + } + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't create rx ring on packet socket: %s", + pcap_strerror(errno)); + *status = PCAP_ERROR; + return -1; } /* memory map the rx ring */ - ringsize = req.tp_block_nr * req.tp_block_size; - handle->bp = mmap(0, ringsize, PROT_READ| PROT_WRITE, MAP_SHARED, - handle->fd, 0); - if (handle->bp == MAP_FAILED) { - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "can't mmap rx ring: %d-%s", - errno, pcap_strerror(errno)); + handle->md.mmapbuflen = req.tp_block_nr * req.tp_block_size; + handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, + PROT_READ|PROT_WRITE, MAP_SHARED, handle->fd, 0); + if (handle->md.mmapbuf == MAP_FAILED) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't mmap rx ring: %s", pcap_strerror(errno)); /* clear the allocated ring on error*/ destroy_ring(handle); - return 0; + *status = PCAP_ERROR; + return -1; } /* allocate a ring for each frame header pointer*/ handle->cc = req.tp_frame_nr; - handle->buffer = malloc(handle->cc * sizeof(struct tpacket_hdr*)); + handle->buffer = malloc(handle->cc * sizeof(union thdr *)); if (!handle->buffer) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "can't allocate ring of frame headers: %s", + pcap_strerror(errno)); + destroy_ring(handle); - return 0; + *status = PCAP_ERROR; + return -1; } /* fill the header ring with proper frame ptr*/ handle->offset = 0; for (i=0; ibp[i*req.tp_block_size]; + void *base = &handle->md.mmapbuf[i*req.tp_block_size]; for (j=0; joffset) { - RING_GET_FRAME(handle) = (struct tpacket_hdr*) base; + RING_GET_FRAME(handle) = base; base += req.tp_frame_size; } } @@ -1914,28 +3807,50 @@ destroy_ring(pcap_t *handle) (void *) &req, sizeof(req)); /* if ring is mapped, unmap it*/ - if (handle->bp) { - /* need to re-compute the ring size */ - unsigned frames_per_block, block_size; - compute_ring_block(handle->bufsize, &block_size, &frames_per_block); - - /* do not perform sanity check here: we can't recover any error */ - munmap(handle->bp, block_size * handle->cc / frames_per_block); - handle->bp = 0; - } - - /* if the header ring is allocated, clear it*/ - if (handle->buffer) { - free(handle->buffer); - handle->buffer = 0; + if (handle->md.mmapbuf) { + /* do not test for mmap failure, as we can't recover from any error */ + munmap(handle->md.mmapbuf, handle->md.mmapbuflen); + handle->md.mmapbuf = NULL; } } +/* + * Special one-shot callback, used for pcap_next() and pcap_next_ex(), + * for Linux mmapped capture. + * + * The problem is that pcap_next() and pcap_next_ex() expect the packet + * data handed to the callback to be valid after the callback returns, + * but pcap_read_linux_mmap() has to release that packet as soon as + * the callback returns (otherwise, the kernel thinks there's still + * at least one unprocessed packet available in the ring, so a select() + * will immediately return indicating that there's data to process), so, + * in the callback, we have to make a copy of the packet. + * + * Yes, this means that, if the capture is using the ring buffer, using + * pcap_next() or pcap_next_ex() requires more copies than using + * pcap_loop() or pcap_dispatch(). If that bothers you, don't use + * pcap_next() or pcap_next_ex(). + */ +static void +pcap_oneshot_mmap(u_char *user, const struct pcap_pkthdr *h, + const u_char *bytes) +{ + struct oneshot_userdata *sp = (struct oneshot_userdata *)user; + + *sp->hdr = *h; + memcpy(sp->pd->md.oneshot_buffer, bytes, h->caplen); + *sp->pkt = sp->pd->md.oneshot_buffer; +} + static void -pcap_close_linux_mmap( pcap_t *handle ) +pcap_cleanup_linux_mmap( pcap_t *handle ) { destroy_ring(handle); - pcap_close_linux(handle); + if (handle->md.oneshot_buffer != NULL) { + free(handle->md.oneshot_buffer); + handle->md.oneshot_buffer = NULL; + } + pcap_cleanup_linux(handle); } @@ -1952,42 +3867,141 @@ pcap_setnonblock_mmap(pcap_t *p, int nonblock, char *errbuf) /* map each value to the corresponding 2's complement, to * preserve the timeout value provided with pcap_set_timeout */ if (nonblock) { - if (p->md.timeout > 0) + if (p->md.timeout >= 0) { + /* + * Timeout is non-negative, so we're not already + * in non-blocking mode; set it to the 2's + * complement, to make it negative, as an + * indication that we're in non-blocking mode. + */ p->md.timeout = p->md.timeout*-1 - 1; - } else - if (p->md.timeout < 0) + } + } else { + if (p->md.timeout < 0) { + /* + * Timeout is negative, so we're not already + * in blocking mode; reverse the previous + * operation, to make the timeout non-negative + * again. + */ p->md.timeout = (p->md.timeout+1)*-1; + } + } return 0; } +static inline union thdr * +pcap_get_ring_frame(pcap_t *handle, int status) +{ + union thdr h; + + h.raw = RING_GET_FRAME(handle); + switch (handle->md.tp_version) { + case TPACKET_V1: + if (status != (h.h1->tp_status ? TP_STATUS_USER : + TP_STATUS_KERNEL)) + return NULL; + break; +#ifdef HAVE_TPACKET2 + case TPACKET_V2: + if (status != (h.h2->tp_status ? TP_STATUS_USER : + TP_STATUS_KERNEL)) + return NULL; + break; +#endif + } + return h.raw; +} + +#ifndef POLLRDHUP +#define POLLRDHUP 0 +#endif + static int pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user) { + int timeout; int pkts = 0; + char c; /* wait for frames availability.*/ - if ((handle->md.timeout >= 0) && !(RING_GET_FRAME(handle)->tp_status)) { + if (!pcap_get_ring_frame(handle, TP_STATUS_USER)) { struct pollfd pollinfo; int ret; pollinfo.fd = handle->fd; pollinfo.events = POLLIN; + if (handle->md.timeout == 0) + timeout = -1; /* block forever */ + else if (handle->md.timeout > 0) + timeout = handle->md.timeout; /* block for that amount of time */ + else + timeout = 0; /* non-blocking mode - poll to pick up errors */ do { - /* poll() requires a negative timeout to wait forever */ - ret = poll(&pollinfo, 1, (handle->md.timeout > 0)? - handle->md.timeout: -1); - if ((ret < 0) && (errno != EINTR)) { + ret = poll(&pollinfo, 1, timeout); + if (ret < 0 && errno != EINTR) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, - "can't poll on packet socket fd %d: %d-%s", - handle->fd, errno, pcap_strerror(errno)); - return -1; - } + "can't poll on packet socket: %s", + pcap_strerror(errno)); + return PCAP_ERROR; + } else if (ret > 0 && + (pollinfo.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) { + /* + * There's some indication other than + * "you can read on this descriptor" on + * the descriptor. + */ + if (pollinfo.revents & (POLLHUP | POLLRDHUP)) { + snprintf(handle->errbuf, + PCAP_ERRBUF_SIZE, + "Hangup on packet socket"); + return PCAP_ERROR; + } + if (pollinfo.revents & POLLERR) { + /* + * A recv() will give us the + * actual error code. + * + * XXX - make the socket non-blocking? + */ + if (recv(handle->fd, &c, sizeof c, + MSG_PEEK) != -1) + continue; /* what, no error? */ + if (errno == ENETDOWN) { + /* + * The device on which we're + * capturing went away. + * + * XXX - we should really return + * PCAP_ERROR_IFACE_NOT_UP, + * but pcap_dispatch() etc. + * aren't defined to return + * that. + */ + snprintf(handle->errbuf, + PCAP_ERRBUF_SIZE, + "The interface went down"); + } else { + snprintf(handle->errbuf, + PCAP_ERRBUF_SIZE, + "Error condition on packet socket: %s", + strerror(errno)); + } + return PCAP_ERROR; + } + if (pollinfo.revents & POLLNVAL) { + snprintf(handle->errbuf, + PCAP_ERRBUF_SIZE, + "Invalid polling request on packet socket"); + return PCAP_ERROR; + } + } /* check for break loop condition on interrupted syscall*/ if (handle->break_loop) { handle->break_loop = 0; - return -2; + return PCAP_ERROR_BREAK; } } while (ret < 0); } @@ -1999,16 +4013,46 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, struct sockaddr_ll *sll; struct pcap_pkthdr pcaphdr; unsigned char *bp; - struct tpacket_hdr* thdr = RING_GET_FRAME(handle); - if (thdr->tp_status == TP_STATUS_KERNEL) + union thdr h; + unsigned int tp_len; + unsigned int tp_mac; + unsigned int tp_snaplen; + unsigned int tp_sec; + unsigned int tp_usec; + + h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER); + if (!h.raw) break; + switch (handle->md.tp_version) { + case TPACKET_V1: + tp_len = h.h1->tp_len; + tp_mac = h.h1->tp_mac; + tp_snaplen = h.h1->tp_snaplen; + tp_sec = h.h1->tp_sec; + tp_usec = h.h1->tp_usec; + break; +#ifdef HAVE_TPACKET2 + case TPACKET_V2: + tp_len = h.h2->tp_len; + tp_mac = h.h2->tp_mac; + tp_snaplen = h.h2->tp_snaplen; + tp_sec = h.h2->tp_sec; + tp_usec = h.h2->tp_nsec / 1000; + break; +#endif + default: + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "unsupported tpacket version %d", + handle->md.tp_version); + return -1; + } /* perform sanity check on internal offset. */ - if (thdr->tp_mac+thdr->tp_snaplen > handle->bufsize) { + if (tp_mac + tp_snaplen > handle->bufsize) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "corrupted frame on kernel ring mac " - "offset %d + caplen %d > frame len %d", - thdr->tp_mac, thdr->tp_snaplen, handle->bufsize); + "offset %u + caplen %u > frame len %d", + tp_mac, tp_snaplen, handle->bufsize); return -1; } @@ -2021,25 +4065,47 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, * Note: alternatively it could be possible to stop applying * the filter when the ring became empty, but it can possibly * happen a lot later... */ - bp = (unsigned char*)thdr + thdr->tp_mac; + bp = (unsigned char*)h.raw + tp_mac; run_bpf = (!handle->md.use_bpf) || ((handle->md.use_bpf>1) && handle->md.use_bpf--); if (run_bpf && handle->fcode.bf_insns && (bpf_filter(handle->fcode.bf_insns, bp, - thdr->tp_len, thdr->tp_snaplen) == 0)) + tp_len, tp_snaplen) == 0)) goto skip; - /* check direction and interface index */ - sll = (void*)thdr + TPACKET_ALIGN(sizeof(*thdr)); - if ((sll->sll_ifindex == handle->md.lo_ifindex) && - (sll->sll_pkttype == PACKET_OUTGOING)) - goto skip; + /* + * Do checks based on packet direction. + */ + sll = (void *)h.raw + TPACKET_ALIGN(handle->md.tp_hdrlen); + if (sll->sll_pkttype == PACKET_OUTGOING) { + /* + * Outgoing packet. + * If this is from the loopback device, reject it; + * we'll see the packet as an incoming packet as well, + * and we don't want to see it twice. + */ + if (sll->sll_ifindex == handle->md.lo_ifindex) + goto skip; + + /* + * If the user only wants incoming packets, reject it. + */ + if (handle->direction == PCAP_D_IN) + goto skip; + } else { + /* + * Incoming packet. + * If the user only wants outgoing packets, reject it. + */ + if (handle->direction == PCAP_D_OUT) + goto skip; + } /* get required packet info from ring header */ - pcaphdr.ts.tv_sec = thdr->tp_sec; - pcaphdr.ts.tv_usec = thdr->tp_usec; - pcaphdr.caplen = thdr->tp_snaplen; - pcaphdr.len = thdr->tp_len; + pcaphdr.ts.tv_sec = tp_sec; + pcaphdr.ts.tv_usec = tp_usec; + pcaphdr.caplen = tp_snaplen; + pcaphdr.len = tp_len; /* if required build in place the sll header*/ if (handle->md.cooked) { @@ -2061,7 +4127,9 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, * don't step on the header when we construct * the sll header. */ - if (bp < (u_char *)thdr + TPACKET_HDRLEN) { + if (bp < (u_char *)h.raw + + TPACKET_ALIGN(handle->md.tp_hdrlen) + + sizeof(struct sockaddr_ll)) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "cooked-mode frame doesn't have room for sll header"); return -1; @@ -2083,6 +4151,41 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, pcaphdr.len += SLL_HDR_LEN; } +#ifdef HAVE_TPACKET2 + if ((handle->md.tp_version == TPACKET_V2) && +#if defined(TP_STATUS_VLAN_VALID) + (h.h2->tp_vlan_tci || (h.h2->tp_status & TP_STATUS_VLAN_VALID)) && +#else + h.h2->tp_vlan_tci && +#endif + handle->md.vlan_offset != -1 && + tp_snaplen >= (unsigned int) handle->md.vlan_offset) { + struct vlan_tag *tag; + + bp -= VLAN_TAG_LEN; + memmove(bp, bp + VLAN_TAG_LEN, handle->md.vlan_offset); + + tag = (struct vlan_tag *)(bp + handle->md.vlan_offset); + tag->vlan_tpid = htons(ETH_P_8021Q); + tag->vlan_tci = htons(h.h2->tp_vlan_tci); + + pcaphdr.caplen += VLAN_TAG_LEN; + pcaphdr.len += VLAN_TAG_LEN; + } +#endif + + /* + * The only way to tell the kernel to cut off the + * packet at a snapshot length is with a filter program; + * if there's no filter program, the kernel won't cut + * the packet off. + * + * Trim the snapshot length to be no longer than the + * specified snapshot length. + */ + if (pcaphdr.caplen > handle->snapshot) + pcaphdr.caplen = handle->snapshot; + /* pass the packet to the user */ pkts++; callback(user, &pcaphdr, bp); @@ -2090,14 +4193,23 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, skip: /* next packet */ - thdr->tp_status = TP_STATUS_KERNEL; + switch (handle->md.tp_version) { + case TPACKET_V1: + h.h1->tp_status = TP_STATUS_KERNEL; + break; +#ifdef HAVE_TPACKET2 + case TPACKET_V2: + h.h2->tp_status = TP_STATUS_KERNEL; + break; +#endif + } if (++handle->offset >= handle->cc) handle->offset = 0; /* check for break loop condition*/ if (handle->break_loop) { handle->break_loop = 0; - return -2; + return PCAP_ERROR_BREAK; } } return pkts; @@ -2107,7 +4219,15 @@ static int pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter) { int n, offset; - int ret = pcap_setfilter_linux(handle, filter); + int ret; + + /* + * Don't rewrite "ret" instructions; we don't need to, as + * we're not reading packets with recvmsg(), and we don't + * want to, as, by not rewriting them, the kernel can avoid + * copying extra data. + */ + ret = pcap_setfilter_linux_common(handle, filter, 1); if (ret < 0) return ret; @@ -2124,7 +4244,7 @@ pcap_setfilter_linux_mmap(pcap_t *handle, struct bpf_program *filter) for (n=0; n < handle->cc; ++n) { if (--handle->offset < 0) handle->offset = handle->cc - 1; - if (RING_GET_FRAME(handle)->tp_status != TP_STATUS_KERNEL) + if (!pcap_get_ring_frame(handle, TP_STATUS_KERNEL)) break; } @@ -2163,6 +4283,8 @@ iface_get_id(int fd, const char *device, char *ebuf) /* * Bind the socket associated with FD to the given device. + * Return 1 on success, 0 if we should try a SOCK_PACKET socket, + * or a PCAP_ERROR_ value on a hard error. */ static int iface_bind(int fd, int ifindex, char *ebuf) @@ -2177,9 +4299,20 @@ iface_bind(int fd, int ifindex, char *ebuf) sll.sll_protocol = htons(ETH_P_ALL); if (bind(fd, (struct sockaddr *) &sll, sizeof(sll)) == -1) { - snprintf(ebuf, PCAP_ERRBUF_SIZE, - "bind: %s", pcap_strerror(errno)); - return -1; + if (errno == ENETDOWN) { + /* + * Return a "network down" indication, so that + * the application can report that rather than + * saying we had a mysterious failure and + * suggest that they report a problem to the + * libpcap developers. + */ + return PCAP_ERROR_IFACE_NOT_UP; + } else { + snprintf(ebuf, PCAP_ERRBUF_SIZE, + "bind: %s", pcap_strerror(errno)); + return PCAP_ERROR; + } } /* Any pending errors, e.g., network is down? */ @@ -2187,27 +4320,36 @@ iface_bind(int fd, int ifindex, char *ebuf) if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &errlen) == -1) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "getsockopt: %s", pcap_strerror(errno)); - return -2; + return 0; } - if (err > 0) { + if (err == ENETDOWN) { + /* + * Return a "network down" indication, so that + * the application can report that rather than + * saying we had a mysterious failure and + * suggest that they report a problem to the + * libpcap developers. + */ + return PCAP_ERROR_IFACE_NOT_UP; + } else if (err > 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "bind: %s", pcap_strerror(err)); - return -2; + return 0; } - return 0; + return 1; } +#ifdef IW_MODE_MONITOR /* * Check whether the device supports the Wireless Extensions. * Returns 1 if it does, 0 if it doesn't, PCAP_ERROR_NO_SUCH_DEVICE * if the device doesn't even exist. */ static int -has_wext(int sock_fd, const char *device) +has_wext(int sock_fd, const char *device, char *ebuf) { -#ifdef IW_MODE_MONITOR struct iwreq ireq; strncpy(ireq.ifr_ifrn.ifrn_name, device, @@ -2215,9 +4357,10 @@ has_wext(int sock_fd, const char *device) ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; if (ioctl(sock_fd, SIOCGIWNAME, &ireq) >= 0) return 1; /* yes */ + snprintf(ebuf, PCAP_ERRBUF_SIZE, + "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); if (errno == ENODEV) return PCAP_ERROR_NO_SUCH_DEVICE; -#endif return 0; } @@ -2226,6 +4369,9 @@ has_wext(int sock_fd, const char *device) * Per me si va ne l'etterno dolore, * ... * Lasciate ogne speranza, voi ch'intrate. + * + * XXX - airmon-ng does special stuff with the Orinoco driver and the + * wlan-ng driver. */ typedef enum { MONITOR_WEXT, @@ -2250,21 +4396,63 @@ typedef enum { static int enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) { -#ifdef IW_MODE_MONITOR /* * XXX - at least some adapters require non-Wireless Extensions * mechanisms to turn monitor mode on. * * Atheros cards might require that a separate "monitor virtual access * point" be created, with later versions of the madwifi driver. + * airmon-ng does "wlanconfig ath create wlandev {if} wlanmode + * monitor -bssid", which apparently spits out a line "athN" + * where "athN" is the monitor mode device. To leave monitor + * mode, it destroys the monitor mode device. * * Some Intel Centrino adapters might require private ioctls to get * radio headers; the ipw2200 and ipw3945 drivers allow you to * configure a separate "rtapN" interface to capture in monitor * mode without preventing the adapter from operating normally. + * (airmon-ng doesn't appear to use that, though.) + * + * It would be Truly Wonderful if mac80211 and nl80211 cleaned this + * up, and if all drivers were converted to mac80211 drivers. + * + * If interface {if} is a mac80211 driver, the file + * /sys/class/net/{if}/phy80211 is a symlink to + * /sys/class/ieee80211/{phydev}, for some {phydev}. + * + * On Fedora 9, with a 2.6.26.3-29 kernel, my Zydas stick, at + * least, has a "wmaster0" device and a "wlan0" device; the + * latter is the one with the IP address. Both show up in + * "tcpdump -D" output. Capturing on the wmaster0 device + * captures with 802.11 headers. * - * It would be Truly Wonderful if mac80211 and nl80211 cleaned this - * up, and if all drivers were converted to mac80211 drivers. + * airmon-ng searches through /sys/class/net for devices named + * monN, starting with mon0; as soon as one *doesn't* exist, + * it chooses that as the monitor device name. If the "iw" + * command exists, it does "iw dev {if} interface add {monif} + * type monitor", where {monif} is the monitor device. It + * then (sigh) sleeps .1 second, and then configures the + * device up. Otherwise, if /sys/class/ieee80211/{phydev}/add_iface + * is a file, it writes {mondev}, without a newline, to that file, + * and again (sigh) sleeps .1 second, and then iwconfig's that + * device into monitor mode and configures it up. Otherwise, + * you can't do monitor mode. + * + * All these devices are "glued" together by having the + * /sys/class/net/{device}/phy80211 links pointing to the same + * place, so, given a wmaster, wlan, or mon device, you can + * find the other devices by looking for devices with + * the same phy80211 link. + * + * To turn monitor mode off, delete the monitor interface, + * either with "iw dev {monif} interface del" or by sending + * {monif}, with no NL, down /sys/class/ieee80211/{phydev}/remove_iface + * + * Note: if you try to create a monitor device named "monN", and + * there's already a "monN" device, it fails, as least with + * the netlink interface (which is what iw uses), with a return + * value of -ENFILE. (Return values are negative errnos.) We + * could probably use that to find an unused device. */ int err; struct iwreq ireq; @@ -2272,15 +4460,24 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) monitor_type montype; int i; __u32 cmd; + struct ifreq ifr; + int oldflags; int args[2]; int channel; /* * Does this device *support* the Wireless Extensions? */ - err = has_wext(sock_fd, device); + err = has_wext(sock_fd, device, handle->errbuf); if (err <= 0) return err; /* either it doesn't or the device doesn't even exist */ + /* + * Start out assuming we have no private extensions to control + * radio metadata. + */ + montype = MONITOR_WEXT; + cmd = 0; + /* * Try to get all the Wireless Extensions private ioctls * supported by this device. @@ -2295,7 +4492,7 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) strncpy(ireq.ifr_ifrn.ifrn_name, device, sizeof ireq.ifr_ifrn.ifrn_name); ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; - ireq.u.data.pointer = args; + ireq.u.data.pointer = (void *)args; ireq.u.data.length = 0; ireq.u.data.flags = 0; if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) != -1) { @@ -2304,185 +4501,189 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) device); return PCAP_ERROR; } - if (errno == EOPNOTSUPP) { - /* - * No private ioctls, so we assume that there's only one - * DLT_ for monitor mode. - */ - return 0; - } - if (errno != E2BIG) { + if (errno != EOPNOTSUPP) { /* - * Failed. + * OK, it's not as if there are no private ioctls. */ - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, - "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); - return PCAP_ERROR; - } - priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args)); - if (priv == NULL) { - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, - "malloc: %s", pcap_strerror(errno)); - return PCAP_ERROR; - } - ireq.u.data.pointer = priv; - if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) { - snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, - "%s: SIOCGIWPRIV: %s", device, pcap_strerror(errno)); - free(priv); - return PCAP_ERROR; - } - - /* - * Look for private ioctls to turn monitor mode on or, if - * monitor mode is on, to set the header type. - */ - montype = MONITOR_WEXT; - cmd = 0; - for (i = 0; i < ireq.u.data.length; i++) { - if (strcmp(priv[i].name, "monitor_type") == 0) { - /* - * Hostap driver, use this one. - * Set monitor mode first. - * You can set it to 0 to get DLT_IEEE80211, - * 1 to get DLT_PRISM, or 2 to get - * DLT_IEEE80211_RADIO_AVS. - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) - break; - if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) - break; - if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) - break; - montype = MONITOR_HOSTAP; - cmd = priv[i].cmd; - break; - } - if (strcmp(priv[i].name, "set_prismhdr") == 0) { - /* - * Prism54 driver, use this one. - * Set monitor mode first. - * You can set it to 2 to get DLT_IEEE80211 - * or 3 or get DLT_PRISM. - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) - break; - if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) - break; - if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) - break; - montype = MONITOR_PRISM54; - cmd = priv[i].cmd; - break; - } - if (strcmp(priv[i].name, "forceprismheader") == 0) { + if (errno != E2BIG) { /* - * RT2570 driver, use this one. - * Do this after turning monitor mode on. - * You can set it to 1 to get DLT_PRISM or 2 - * to get DLT_IEEE80211. + * Failed. */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) - break; - if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) - break; - if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) - break; - montype = MONITOR_RT2570; - cmd = priv[i].cmd; - break; + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: SIOCGIWPRIV: %s", device, + pcap_strerror(errno)); + return PCAP_ERROR; } - if (strcmp(priv[i].name, "forceprism") == 0) { - /* - * RT73 driver, use this one. - * Do this after turning monitor mode on. - * Its argument is a *string*; you can - * set it to "1" to get DLT_PRISM or "2" - * to get DLT_IEEE80211. - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR) - break; - if (priv[i].set_args & IW_PRIV_SIZE_FIXED) - break; - montype = MONITOR_RT73; - cmd = priv[i].cmd; - break; + + /* + * OK, try to get the list of private ioctls. + */ + priv = malloc(ireq.u.data.length * sizeof (struct iw_priv_args)); + if (priv == NULL) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "malloc: %s", pcap_strerror(errno)); + return PCAP_ERROR; } - if (strcmp(priv[i].name, "prismhdr") == 0) { - /* - * One of the RTL8xxx drivers, use this one. - * It can only be done after monitor mode - * has been turned on. You can set it to 1 - * to get DLT_PRISM or 0 to get DLT_IEEE80211. - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) - break; - if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) - break; - if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) - break; - montype = MONITOR_RTL8XXX; - cmd = priv[i].cmd; - break; + ireq.u.data.pointer = (void *)priv; + if (ioctl(sock_fd, SIOCGIWPRIV, &ireq) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: SIOCGIWPRIV: %s", device, + pcap_strerror(errno)); + free(priv); + return PCAP_ERROR; } - if (strcmp(priv[i].name, "rfmontx") == 0) { - /* - * RT2500 or RT61 driver, use this one. - * It has one one-byte parameter; set - * u.data.length to 1 and u.data.pointer to - * point to the parameter. - * It doesn't itself turn monitor mode on. - * You can set it to 1 to allow transmitting - * in monitor mode(?) and get DLT_IEEE80211, - * or set it to 0 to disallow transmitting in - * monitor mode(?) and get DLT_PRISM. - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) - break; - if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2) + + /* + * Look for private ioctls to turn monitor mode on or, if + * monitor mode is on, to set the header type. + */ + for (i = 0; i < ireq.u.data.length; i++) { + if (strcmp(priv[i].name, "monitor_type") == 0) { + /* + * Hostap driver, use this one. + * Set monitor mode first. + * You can set it to 0 to get DLT_IEEE80211, + * 1 to get DLT_PRISM, 2 to get + * DLT_IEEE80211_RADIO_AVS, and, with more + * recent versions of the driver, 3 to get + * DLT_IEEE80211_RADIO. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + break; + if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) + break; + montype = MONITOR_HOSTAP; + cmd = priv[i].cmd; break; - montype = MONITOR_RT2500; - cmd = priv[i].cmd; - break; - } - if (strcmp(priv[i].name, "monitor") == 0) { - /* - * Either ACX100 or hostap, use this one. - * It turns monitor mode on. - * If it takes two arguments, it's ACX100; - * the first argument is 1 for DLT_PRISM - * or 2 for DLT_IEEE80211, and the second - * argument is the channel on which to - * run. If it takes one argument, it's - * HostAP, and the argument is 2 for - * DLT_IEEE80211 and 3 for DLT_PRISM. - * - * If we see this, we don't quit, as this - * might be a version of the hostap driver - * that also supports "monitor_type". - */ - if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + } + if (strcmp(priv[i].name, "set_prismhdr") == 0) { + /* + * Prism54 driver, use this one. + * Set monitor mode first. + * You can set it to 2 to get DLT_IEEE80211 + * or 3 or get DLT_PRISM. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + break; + if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) + break; + montype = MONITOR_PRISM54; + cmd = priv[i].cmd; break; - if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + } + if (strcmp(priv[i].name, "forceprismheader") == 0) { + /* + * RT2570 driver, use this one. + * Do this after turning monitor mode on. + * You can set it to 1 to get DLT_PRISM or 2 + * to get DLT_IEEE80211. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + break; + if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) + break; + montype = MONITOR_RT2570; + cmd = priv[i].cmd; break; - switch (priv[i].set_args & IW_PRIV_SIZE_MASK) { - - case 1: - montype = MONITOR_PRISM; + } + if (strcmp(priv[i].name, "forceprism") == 0) { + /* + * RT73 driver, use this one. + * Do this after turning monitor mode on. + * Its argument is a *string*; you can + * set it to "1" to get DLT_PRISM or "2" + * to get DLT_IEEE80211. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_CHAR) + break; + if (priv[i].set_args & IW_PRIV_SIZE_FIXED) + break; + montype = MONITOR_RT73; cmd = priv[i].cmd; break; - - case 2: - montype = MONITOR_ACX100; + } + if (strcmp(priv[i].name, "prismhdr") == 0) { + /* + * One of the RTL8xxx drivers, use this one. + * It can only be done after monitor mode + * has been turned on. You can set it to 1 + * to get DLT_PRISM or 0 to get DLT_IEEE80211. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + break; + if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 1) + break; + montype = MONITOR_RTL8XXX; cmd = priv[i].cmd; break; - - default: + } + if (strcmp(priv[i].name, "rfmontx") == 0) { + /* + * RT2500 or RT61 driver, use this one. + * It has one one-byte parameter; set + * u.data.length to 1 and u.data.pointer to + * point to the parameter. + * It doesn't itself turn monitor mode on. + * You can set it to 1 to allow transmitting + * in monitor mode(?) and get DLT_IEEE80211, + * or set it to 0 to disallow transmitting in + * monitor mode(?) and get DLT_PRISM. + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if ((priv[i].set_args & IW_PRIV_SIZE_MASK) != 2) + break; + montype = MONITOR_RT2500; + cmd = priv[i].cmd; break; } + if (strcmp(priv[i].name, "monitor") == 0) { + /* + * Either ACX100 or hostap, use this one. + * It turns monitor mode on. + * If it takes two arguments, it's ACX100; + * the first argument is 1 for DLT_PRISM + * or 2 for DLT_IEEE80211, and the second + * argument is the channel on which to + * run. If it takes one argument, it's + * HostAP, and the argument is 2 for + * DLT_IEEE80211 and 3 for DLT_PRISM. + * + * If we see this, we don't quit, as this + * might be a version of the hostap driver + * that also supports "monitor_type". + */ + if ((priv[i].set_args & IW_PRIV_TYPE_MASK) != IW_PRIV_TYPE_INT) + break; + if (!(priv[i].set_args & IW_PRIV_SIZE_FIXED)) + break; + switch (priv[i].set_args & IW_PRIV_SIZE_MASK) { + + case 1: + montype = MONITOR_PRISM; + cmd = priv[i].cmd; + break; + + case 2: + montype = MONITOR_ACX100; + cmd = priv[i].cmd; + break; + + default: + break; + } + } } + free(priv); } - free(priv); /* * XXX - ipw3945? islism? @@ -2560,7 +4761,7 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) * Note that we have to put the old mode back * when we close the device. */ - handle->md.must_clear |= MUST_CLEAR_RFMON; + handle->md.must_do_on_close |= MUST_CLEAR_RFMON; /* * Add this to the list of pcaps to close @@ -2577,7 +4778,29 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) } /* - * First, turn monitor mode on. + * First, take the interface down if it's up; otherwise, we + * might get EBUSY. + */ + memset(&ifr, 0, sizeof(ifr)); + strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); + if (ioctl(sock_fd, SIOCGIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't get flags: %s", device, strerror(errno)); + return PCAP_ERROR; + } + oldflags = 0; + if (ifr.ifr_flags & IFF_UP) { + oldflags = ifr.ifr_flags; + ifr.ifr_flags &= ~IFF_UP; + if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't set flags: %s", device, strerror(errno)); + return PCAP_ERROR; + } + } + + /* + * Then turn monitor mode on. */ strncpy(ireq.ifr_ifrn.ifrn_name, device, sizeof ireq.ifr_ifrn.ifrn_name); @@ -2586,10 +4809,23 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) if (ioctl(sock_fd, SIOCSIWMODE, &ireq) == -1) { /* * Scientist, you've failed. + * Bring the interface back up if we shut it down. */ + ifr.ifr_flags = oldflags; + if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't set flags: %s", device, strerror(errno)); + return PCAP_ERROR; + } return PCAP_ERROR_RFMON_NOTSUP; } + /* + * XXX - airmon-ng does "iwconfig {if} key off" after setting + * monitor mode and setting the channel, and then does + * "iwconfig up". + */ + /* * Now select the appropriate radio header. */ @@ -2603,8 +4839,19 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) case MONITOR_HOSTAP: /* - * Select the AVS header if we can, otherwise - * select the Prism header. + * Try to select the radiotap header. + */ + memset(&ireq, 0, sizeof ireq); + strncpy(ireq.ifr_ifrn.ifrn_name, device, + sizeof ireq.ifr_ifrn.ifrn_name); + ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; + args[0] = 3; /* request radiotap header */ + memcpy(ireq.u.name, args, sizeof (int)); + if (ioctl(sock_fd, cmd, &ireq) != -1) + break; /* success */ + + /* + * That failed. Try to select the AVS header. */ memset(&ireq, 0, sizeof ireq); strncpy(ireq.ifr_ifrn.ifrn_name, device, @@ -2612,18 +4859,19 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; args[0] = 2; /* request AVS header */ memcpy(ireq.u.name, args, sizeof (int)); - if (ioctl(sock_fd, cmd, &ireq) == -1) { - /* - * Failure - try the Prism header. - */ - memset(&ireq, 0, sizeof ireq); - strncpy(ireq.ifr_ifrn.ifrn_name, device, - sizeof ireq.ifr_ifrn.ifrn_name); - ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; - args[0] = 1; /* request Prism header */ - memcpy(ireq.u.name, args, sizeof (int)); - ioctl(sock_fd, cmd, &ireq); - } + if (ioctl(sock_fd, cmd, &ireq) != -1) + break; /* success */ + + /* + * That failed. Try to select the Prism header. + */ + memset(&ireq, 0, sizeof ireq); + strncpy(ireq.ifr_ifrn.ifrn_name, device, + sizeof ireq.ifr_ifrn.ifrn_name); + ireq.ifr_ifrn.ifrn_name[sizeof ireq.ifr_ifrn.ifrn_name - 1] = 0; + args[0] = 1; /* request Prism header */ + memcpy(ireq.u.name, args, sizeof (int)); + ioctl(sock_fd, cmd, &ireq); break; case MONITOR_PRISM: @@ -2730,11 +4978,37 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) break; } + /* + * Now bring the interface back up if we brought it down. + */ + if (oldflags != 0) { + ifr.ifr_flags = oldflags; + if (ioctl(sock_fd, SIOCSIFFLAGS, &ifr) == -1) { + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: Can't set flags: %s", device, strerror(errno)); + + /* + * At least try to restore the old mode on the + * interface. + */ + if (ioctl(handle->fd, SIOCSIWMODE, &ireq) == -1) { + /* + * Scientist, you've failed. + */ + fprintf(stderr, + "Can't restore interface wireless mode (SIOCSIWMODE failed: %s).\n" + "Please adjust manually.\n", + strerror(errno)); + } + return PCAP_ERROR; + } + } + /* * Note that we have to put the old mode back when we * close the device. */ - handle->md.must_clear |= MUST_CLEAR_RFMON; + handle->md.must_do_on_close |= MUST_CLEAR_RFMON; /* * Add this to the list of pcaps to close when we exit. @@ -2742,14 +5016,148 @@ enter_rfmon_mode_wext(pcap_t *handle, int sock_fd, const char *device) pcap_add_to_pcaps_to_close(handle); return 1; -#else +} +#endif /* IW_MODE_MONITOR */ + +/* + * Try various mechanisms to enter monitor mode. + */ +static int +enter_rfmon_mode(pcap_t *handle, int sock_fd, const char *device) +{ +#if defined(HAVE_LIBNL) || defined(IW_MODE_MONITOR) + int ret; +#endif + +#ifdef HAVE_LIBNL + ret = enter_rfmon_mode_mac80211(handle, sock_fd, device); + if (ret < 0) + return ret; /* error attempting to do so */ + if (ret == 1) + return 1; /* success */ +#endif /* HAVE_LIBNL */ + +#ifdef IW_MODE_MONITOR + ret = enter_rfmon_mode_wext(handle, sock_fd, device); + if (ret < 0) + return ret; /* error attempting to do so */ + if (ret == 1) + return 1; /* success */ +#endif /* IW_MODE_MONITOR */ + /* - * We don't have the Wireless Extensions available, so we can't - * do monitor mode. + * Either none of the mechanisms we know about work or none + * of those mechanisms are available, so we can't do monitor + * mode. */ return 0; +} + +/* + * Find out if we have any form of fragmentation/reassembly offloading. + * + * We do so using SIOCETHTOOL checking for various types of offloading; + * if SIOCETHTOOL isn't defined, or we don't have any #defines for any + * of the types of offloading, there's nothing we can do to check, so + * we just say "no, we don't". + */ +#if defined(SIOCETHTOOL) && (defined(ETHTOOL_GTSO) || defined(ETHTOOL_GUFO) || defined(ETHTOOL_GGSO) || defined(ETHTOOL_GFLAGS) || defined(ETHTOOL_GGRO)) +static int +iface_ethtool_ioctl(pcap_t *handle, int cmd, const char *cmdname) +{ + struct ifreq ifr; + struct ethtool_value eval; + + memset(&ifr, 0, sizeof(ifr)); + strncpy(ifr.ifr_name, handle->opt.source, sizeof(ifr.ifr_name)); + eval.cmd = cmd; + ifr.ifr_data = (caddr_t)&eval; + if (ioctl(handle->fd, SIOCETHTOOL, &ifr) == -1) { + if (errno == EOPNOTSUPP || errno == EINVAL) { + /* + * OK, let's just return 0, which, in our + * case, either means "no, what we're asking + * about is not enabled" or "all the flags + * are clear (i.e., nothing is enabled)". + */ + return 0; + } + snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, + "%s: SIOETHTOOL(%s) ioctl failed: %s", handle->opt.source, + cmdname, strerror(errno)); + return -1; + } + return eval.data; +} + +static int +iface_get_offload(pcap_t *handle) +{ + int ret; + +#ifdef ETHTOOL_GTSO + ret = iface_ethtool_ioctl(handle, ETHTOOL_GTSO, "ETHTOOL_GTSO"); + if (ret == -1) + return -1; + if (ret) + return 1; /* TCP segmentation offloading on */ +#endif + +#ifdef ETHTOOL_GUFO + ret = iface_ethtool_ioctl(handle, ETHTOOL_GUFO, "ETHTOOL_GUFO"); + if (ret == -1) + return -1; + if (ret) + return 1; /* UDP fragmentation offloading on */ +#endif + +#ifdef ETHTOOL_GGSO + /* + * XXX - will this cause large unsegmented packets to be + * handed to PF_PACKET sockets on transmission? If not, + * this need not be checked. + */ + ret = iface_ethtool_ioctl(handle, ETHTOOL_GGSO, "ETHTOOL_GGSO"); + if (ret == -1) + return -1; + if (ret) + return 1; /* generic segmentation offloading on */ +#endif + +#ifdef ETHTOOL_GFLAGS + ret = iface_ethtool_ioctl(handle, ETHTOOL_GFLAGS, "ETHTOOL_GFLAGS"); + if (ret == -1) + return -1; + if (ret & ETH_FLAG_LRO) + return 1; /* large receive offloading on */ +#endif + +#ifdef ETHTOOL_GGRO + /* + * XXX - will this cause large reassembled packets to be + * handed to PF_PACKET sockets on receipt? If not, + * this need not be checked. + */ + ret = iface_ethtool_ioctl(handle, ETHTOOL_GGRO, "ETHTOOL_GGRO"); + if (ret == -1) + return -1; + if (ret) + return 1; /* generic (large) receive offloading on */ #endif + + return 0; +} +#else /* SIOCETHTOOL */ +static int +iface_get_offload(pcap_t *handle _U_) +{ + /* + * XXX - do we need to get this information if we don't + * have the ethtool ioctls? If so, how do we do that? + */ + return 0; } +#endif /* SIOCETHTOOL */ #endif /* HAVE_PF_PACKET_SOCKETS */ @@ -2774,7 +5182,18 @@ activate_old(pcap_t *handle) if (handle->fd == -1) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); - return PCAP_ERROR; + if (errno == EPERM || errno == EACCES) { + /* + * You don't have permission to open the + * socket. + */ + return PCAP_ERROR_PERM_DENIED; + } else { + /* + * Other error. + */ + return PCAP_ERROR; + } } /* It worked - we are using the old interface */ @@ -2785,7 +5204,7 @@ activate_old(pcap_t *handle) /* Bind to the given device */ - if (!device) { + if (strcmp(device, "any") == 0) { strncpy(handle->errbuf, "pcap_activate: The \"any\" device isn't supported on 2.0[.x]-kernel systems", PCAP_ERRBUF_SIZE); return PCAP_ERROR; @@ -2804,7 +5223,7 @@ activate_old(pcap_t *handle) * Try to find the DLT_ type corresponding to that * link-layer type. */ - map_arphrd_to_dlt(handle, arptype, 0); + map_arphrd_to_dlt(handle, handle->fd, arptype, device, 0); if (handle->linktype == -1) { snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "unknown arptype %d", arptype); @@ -2850,7 +5269,7 @@ activate_old(pcap_t *handle) pcap_strerror(errno)); return PCAP_ERROR; } - handle->md.must_clear |= MUST_CLEAR_PROMISC; + handle->md.must_do_on_close |= MUST_CLEAR_PROMISC; /* * Add this to the list of pcaps @@ -2932,6 +5351,12 @@ activate_old(pcap_t *handle) */ handle->offset = 0; + /* + * SOCK_PACKET sockets don't supply information from + * stripped VLAN tags. + */ + handle->md.vlan_offset = -1; /* unknown */ + return 1; } @@ -3009,14 +5434,14 @@ iface_get_arptype(int fd, const char *device, char *ebuf) strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFHWADDR, &ifr) == -1) { + snprintf(ebuf, PCAP_ERRBUF_SIZE, + "SIOCGIFHWADDR: %s", pcap_strerror(errno)); if (errno == ENODEV) { /* * No such device. */ return PCAP_ERROR_NO_SUCH_DEVICE; } - snprintf(ebuf, PCAP_ERRBUF_SIZE, - "SIOCGIFHWADDR: %s", pcap_strerror(errno)); return PCAP_ERROR; } @@ -3025,7 +5450,7 @@ iface_get_arptype(int fd, const char *device, char *ebuf) #ifdef SO_ATTACH_FILTER static int -fix_program(pcap_t *handle, struct sock_fprog *fcode) +fix_program(pcap_t *handle, struct sock_fprog *fcode, int is_mmapped) { size_t prog_size; register int i; @@ -3058,26 +5483,33 @@ fix_program(pcap_t *handle, struct sock_fprog *fcode) case BPF_RET: /* - * It's a return instruction; is the snapshot - * length a constant, rather than the contents - * of the accumulator? + * It's a return instruction; are we capturing + * in memory-mapped mode? */ - if (BPF_MODE(p->code) == BPF_K) { + if (!is_mmapped) { /* - * Yes - if the value to be returned, - * i.e. the snapshot length, is anything - * other than 0, make it 65535, so that - * the packet is truncated by "recvfrom()", - * not by the filter. - * - * XXX - there's nothing we can easily do - * if it's getting the value from the - * accumulator; we'd have to insert - * code to force non-zero values to be - * 65535. + * No; is the snapshot length a constant, + * rather than the contents of the + * accumulator? */ - if (p->k != 0) - p->k = 65535; + if (BPF_MODE(p->code) == BPF_K) { + /* + * Yes - if the value to be returned, + * i.e. the snapshot length, is + * anything other than 0, make it + * 65535, so that the packet is + * truncated by "recvfrom()", + * not by the filter. + * + * XXX - there's nothing we can + * easily do if it's getting the + * value from the accumulator; we'd + * have to insert code to force + * non-zero values to be 65535. + */ + if (p->k != 0) + p->k = 65535; + } } break; @@ -3131,13 +5563,19 @@ fix_offset(struct bpf_insn *p) * header. */ p->k -= SLL_HDR_LEN; + } else if (p->k == 0) { + /* + * It's the packet type field; map it to the special magic + * kernel offset for that field. + */ + p->k = SKF_AD_OFF + SKF_AD_PKTTYPE; } else if (p->k == 14) { /* * It's the protocol field; map it to the special magic * kernel offset for that field. */ p->k = SKF_AD_OFF + SKF_AD_PROTOCOL; - } else { + } else if ((bpf_int32)(p->k) > 0) { /* * It's within the header, but it's not one of those * fields; we can't do that in the kernel, so punt