* Extraction/creation by Jeffrey Mogul, DECWRL
*/
-#ifndef lint
-static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.68 2002-08-02 03:28:05 guy Exp $ (LBL)";
-#endif
-
#ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
#endif
#include <sys/types.h>
#include <netinet/tcp.h>
#include <netinet/tcpip.h>
-#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
+/*
+ * Make "pcap.h" not include "pcap/bpf.h"; we are going to include the
+ * native OS version, as we need various BPF ioctls from it.
+ */
+#define PCAP_DONT_INCLUDE_PCAP_BPF_H
+#include <net/bpf.h>
+
#include "pcap-int.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
+/*
+ * FDDI packets are padded to make everything line up on a nice boundary.
+ */
+#define PCAP_FDDIPAD 3
+
+/*
+ * Private data for capturing on Ultrix and DEC OSF/1^WDigital UNIX^W^W
+ * Tru64 UNIX packetfilter devices.
+ */
+struct pcap_pf {
+ int filtering_in_kernel; /* using kernel filter */
+ u_long TotPkts; /* can't oflow for 79 hrs on ether */
+ u_long TotAccepted; /* count accepted by filter */
+ u_long TotDrops; /* count of dropped packets */
+ long TotMissed; /* missed by i/f during this run */
+ long OrigMissed; /* missed by i/f before this run */
+};
+
+static int pcap_setfilter_pf(pcap_t *, struct bpf_program *);
+
/*
* BUFSPACE is the size in bytes of the packet read buffer. Most tcpdump
* applications aren't going to need more than 200 bytes of packet header
*/
#define BUFSPACE (200 * 256)
-int
-pcap_read(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
+static int
+pcap_read_pf(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
{
+ struct pcap_pf *pf = pc->priv;
register u_char *p, *bp;
- struct bpf_insn *fcode;
register int cc, n, buflen, inc;
register struct enstamp *sp;
-#ifdef LBL_ALIGN
struct enstamp stamp;
-#endif
-#ifdef PCAP_FDDIPAD
- register int pad;
-#endif
+ register u_int pad;
- fcode = pc->md.use_bpf ? NULL : pc->fcode.bf_insns;
again:
cc = pc->cc;
if (cc == 0) {
(void)lseek(pc->fd, 0L, SEEK_SET);
goto again;
}
- snprintf(pc->errbuf, sizeof(pc->errbuf), "pf read: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(pc->errbuf,
+ sizeof(pc->errbuf), errno, "pf read");
return (-1);
}
- bp = pc->buffer + pc->offset;
+ bp = (u_char *)pc->buffer + pc->offset;
} else
bp = pc->bp;
/*
* Loop through each packet.
+ *
+ * This assumes that a single buffer of packets will have
+ * <= INT_MAX packets, so the packet count doesn't overflow.
*/
n = 0;
-#ifdef PCAP_FDDIPAD
- if (pc->linktype == DLT_FDDI)
- pad = pcap_fddipad;
- else
- pad = 0;
-#endif
+ pad = pc->fddipad;
while (cc > 0) {
+ /*
+ * Has "pcap_breakloop()" been called?
+ * If so, return immediately - if we haven't read any
+ * packets, clear the flag and return -2 to indicate
+ * that we were told to break out of the loop, otherwise
+ * leave the flag set, so that the *next* call will break
+ * out of the loop without having read any packets, and
+ * return the number of packets we've processed so far.
+ */
+ if (pc->break_loop) {
+ if (n == 0) {
+ pc->break_loop = 0;
+ return (-2);
+ } else {
+ pc->cc = cc;
+ pc->bp = bp;
+ return (n);
+ }
+ }
if (cc < sizeof(*sp)) {
snprintf(pc->errbuf, sizeof(pc->errbuf),
"pf short read (%d)", cc);
return (-1);
}
-#ifdef LBL_ALIGN
if ((long)bp & 3) {
sp = &stamp;
memcpy((char *)sp, (char *)bp, sizeof(*sp));
} else
-#endif
sp = (struct enstamp *)bp;
if (sp->ens_stamplen != sizeof(*sp)) {
snprintf(pc->errbuf, sizeof(pc->errbuf),
inc = ENALIGN(buflen + sp->ens_stamplen);
cc -= inc;
bp += inc;
-#ifdef PCAP_FDDIPAD
- p += pad;
- buflen -= pad;
-#endif
- pc->md.TotPkts++;
- pc->md.TotDrops += sp->ens_dropped;
- pc->md.TotMissed = sp->ens_ifoverflows;
- if (pc->md.OrigMissed < 0)
- pc->md.OrigMissed = pc->md.TotMissed;
+ pf->TotPkts++;
+ pf->TotDrops += sp->ens_dropped;
+ pf->TotMissed = sp->ens_ifoverflows;
+ if (pf->OrigMissed < 0)
+ pf->OrigMissed = pf->TotMissed;
/*
* Short-circuit evaluation: if using BPF filter
- * in kernel, no need to do it now.
+ * in kernel, no need to do it now - we already know
+ * the packet passed the filter.
+ *
+ * Note: the filter code was generated assuming
+ * that pc->fddipad was the amount of padding
+ * before the header, as that's what's required
+ * in the kernel, so we run the filter before
+ * skipping that padding.
*/
- if (fcode == NULL ||
- bpf_filter(fcode, p, sp->ens_count, buflen)) {
+ if (pf->filtering_in_kernel ||
+ pcap_filter(pc->fcode.bf_insns, p, sp->ens_count, buflen)) {
struct pcap_pkthdr h;
- pc->md.TotAccepted++;
+ pf->TotAccepted++;
h.ts = sp->ens_tstamp;
-#ifdef PCAP_FDDIPAD
h.len = sp->ens_count - pad;
-#else
- h.len = sp->ens_count;
-#endif
+ p += pad;
+ buflen -= pad;
h.caplen = buflen;
(*callback)(user, &h, p);
- if (++n >= cnt && cnt > 0) {
+ if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
pc->cc = cc;
pc->bp = bp;
return (n);
return (n);
}
-int
-pcap_stats(pcap_t *p, struct pcap_stat *ps)
+static int
+pcap_inject_pf(pcap_t *p, const void *buf, int size)
{
+ int ret;
+
+ ret = write(p->fd, buf, size);
+ if (ret == -1) {
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "send");
+ return (-1);
+ }
+ return (ret);
+}
+
+static int
+pcap_stats_pf(pcap_t *p, struct pcap_stat *ps)
+{
+ struct pcap_pf *pf = p->priv;
/*
* If packet filtering is being done in the kernel:
* full.
*
* "ps_ifdrop" counts packets dropped by the network
- * inteface (regardless of whether they would have passed
+ * interface (regardless of whether they would have passed
* the input filter, of course).
*
* If packet filtering is not being done in the kernel:
* the userland filter.
*
* "ps_ifdrop" counts packets dropped by the network
- * inteface (regardless of whether they would have passed
+ * interface (regardless of whether they would have passed
* the input filter, of course).
*
* These statistics don't include packets not yet read from
* the kernel by libpcap, but they may include packets not
* yet read from libpcap by the application.
*/
- ps->ps_recv = p->md.TotAccepted;
- ps->ps_drop = p->md.TotDrops;
- ps->ps_ifdrop = p->md.TotMissed - p->md.OrigMissed;
+ ps->ps_recv = pf->TotAccepted;
+ ps->ps_drop = pf->TotDrops;
+ ps->ps_ifdrop = pf->TotMissed - pf->OrigMissed;
return (0);
}
-pcap_t *
-pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
+/*
+ * We include the OS's <net/bpf.h>, not our "pcap/bpf.h", so we probably
+ * don't get DLT_DOCSIS defined.
+ */
+#ifndef DLT_DOCSIS
+#define DLT_DOCSIS 143
+#endif
+
+static int
+pcap_activate_pf(pcap_t *p)
{
- pcap_t *p;
+ struct pcap_pf *pf = p->priv;
short enmode;
int backlog = -1; /* request the most */
struct enfilter Filter;
struct endevp devparams;
+ int err;
- p = (pcap_t *)malloc(sizeof(*p));
- if (p == NULL) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE,
- "pcap_open_live: %s", pcap_strerror(errno));
- return (0);
- }
- memset(p, 0, sizeof(*p));
- p->fd = pfopen(device, O_RDONLY);
+ /*
+ * Initially try a read/write open (to allow the inject
+ * method to work). If that fails due to permission
+ * issues, fall back to read-only. This allows a
+ * non-root user to be granted specific access to pcap
+ * capabilities via file permissions.
+ *
+ * XXX - we should have an API that has a flag that
+ * controls whether to open read-only or read-write,
+ * so that denial of permission to send (or inability
+ * to send, if sending packets isn't supported on
+ * the device in question) can be indicated at open
+ * time.
+ *
+ * XXX - we assume here that "pfopen()" does not, in fact, modify
+ * its argument, even though it takes a "char *" rather than a
+ * "const char *" as its first argument. That appears to be
+ * the case, at least on Digital UNIX 4.0.
+ *
+ * XXX - is there an error that means "no such device"? Is
+ * there one that means "that device doesn't support pf"?
+ */
+ p->fd = pfopen(p->opt.device, O_RDWR);
+ if (p->fd == -1 && errno == EACCES)
+ p->fd = pfopen(p->opt.device, O_RDONLY);
if (p->fd < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "pf open: %s: %s\n\
-your system may not be properly configured; see the packetfilter(4) man page\n"
- device, pcap_strerror(errno));
+ if (errno == EACCES) {
+ snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+ "pf open: %s: Permission denied\n"
+"your system may not be properly configured; see the packetfilter(4) man page",
+ p->opt.device);
+ err = PCAP_ERROR_PERM_DENIED;
+ } else {
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "pf open: %s", p->opt.device);
+ err = PCAP_ERROR;
+ }
goto bad;
}
- p->md.OrigMissed = -1;
- enmode = ENTSTAMP|ENBATCH|ENNONEXCL;
- if (promisc)
+
+ /*
+ * Turn a negative snapshot value (invalid), a snapshot value of
+ * 0 (unspecified), or a value bigger than the normal maximum
+ * value, into the maximum allowed value.
+ *
+ * If some application really *needs* a bigger snapshot
+ * length, we should just increase MAXIMUM_SNAPLEN.
+ */
+ if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
+ p->snapshot = MAXIMUM_SNAPLEN;
+
+ pf->OrigMissed = -1;
+ enmode = ENTSTAMP|ENNONEXCL;
+ if (!p->opt.immediate)
+ enmode |= ENBATCH;
+ if (p->opt.promisc)
enmode |= ENPROMISC;
if (ioctl(p->fd, EIOCMBIS, (caddr_t)&enmode) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCMBIS: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCMBIS");
+ err = PCAP_ERROR;
goto bad;
}
#ifdef ENCOPYALL
#endif
/* set the backlog */
if (ioctl(p->fd, EIOCSETW, (caddr_t)&backlog) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSETW: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCSETW");
+ err = PCAP_ERROR;
goto bad;
}
/* discover interface type */
if (ioctl(p->fd, EIOCDEVP, (caddr_t)&devparams) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCDEVP: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCDEVP");
+ err = PCAP_ERROR;
goto bad;
}
/* HACK: to compile prior to Ultrix 4.2 */
case ENDT_10MB:
p->linktype = DLT_EN10MB;
p->offset = 2;
+ /*
+ * This is (presumably) a real Ethernet capture; 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
+ * Termination System is putting out onto an Ethernet (it
+ * doesn't put an Ethernet header onto the wire, it puts raw
+ * DOCSIS frames out on the wire inside the low-level
+ * Ethernet framing).
+ */
+ p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
+ /*
+ * If that fails, just leave the list empty.
+ */
+ if (p->dlt_list != NULL) {
+ p->dlt_list[0] = DLT_EN10MB;
+ p->dlt_list[1] = DLT_DOCSIS;
+ p->dlt_count = 2;
+ }
break;
case ENDT_FDDI:
* framing", there's not much we can do, as that
* doesn't specify a particular type of header.
*/
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown data-link type %u",
- devparams.end_dev_type);
+ snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+ "unknown data-link type %u", devparams.end_dev_type);
+ err = PCAP_ERROR;
goto bad;
}
/* set truncation */
-#ifdef PCAP_FDDIPAD
- if (p->linktype == DLT_FDDI)
+ if (p->linktype == DLT_FDDI) {
+ p->fddipad = PCAP_FDDIPAD;
+
/* packetfilter includes the padding in the snapshot */
- snaplen += pcap_fddipad;
-#endif
- if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&snaplen) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCTRUNCATE: %s",
- pcap_strerror(errno));
+ p->snapshot += PCAP_FDDIPAD;
+ } else
+ p->fddipad = 0;
+ if (ioctl(p->fd, EIOCTRUNCATE, (caddr_t)&p->snapshot) < 0) {
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCTRUNCATE");
+ err = PCAP_ERROR;
goto bad;
}
- p->snapshot = snaplen;
/* accept all packets */
memset(&Filter, 0, sizeof(Filter));
Filter.enf_Priority = 37; /* anything > 2 */
Filter.enf_FilterLen = 0; /* means "always true" */
if (ioctl(p->fd, EIOCSETF, (caddr_t)&Filter) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSETF: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCSETF");
+ err = PCAP_ERROR;
goto bad;
}
- if (to_ms != 0) {
+ if (p->opt.timeout != 0) {
struct timeval timeout;
- timeout.tv_sec = to_ms / 1000;
- timeout.tv_usec = (to_ms * 1000) % 1000000;
+ timeout.tv_sec = p->opt.timeout / 1000;
+ timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
if (ioctl(p->fd, EIOCSRTIMEOUT, (caddr_t)&timeout) < 0) {
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "EIOCSRTIMEOUT: %s",
- pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "EIOCSRTIMEOUT");
+ err = PCAP_ERROR;
goto bad;
}
}
+
p->bufsize = BUFSPACE;
- p->buffer = (u_char*)malloc(p->bufsize + p->offset);
+ p->buffer = malloc(p->bufsize + p->offset);
+ if (p->buffer == NULL) {
+ pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "malloc");
+ err = PCAP_ERROR;
+ goto bad;
+ }
- return (p);
+ /*
+ * "select()" and "poll()" work on packetfilter devices.
+ */
+ p->selectable_fd = p->fd;
+
+ p->read_op = pcap_read_pf;
+ p->inject_op = pcap_inject_pf;
+ p->setfilter_op = pcap_setfilter_pf;
+ p->setdirection_op = NULL; /* Not implemented. */
+ p->set_datalink_op = NULL; /* can't change data link type */
+ p->getnonblock_op = pcap_getnonblock_fd;
+ p->setnonblock_op = pcap_setnonblock_fd;
+ p->stats_op = pcap_stats_pf;
+
+ return (0);
bad:
- if (p->fd >= 0)
- close(p->fd);
- free(p);
- return (NULL);
+ pcap_cleanup_live_common(p);
+ return (err);
}
-int
-pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
+pcap_t *
+pcap_create_interface(const char *device _U_, char *ebuf)
{
+ pcap_t *p;
+
+ p = PCAP_CREATE_COMMON(ebuf, struct pcap_pf);
+ if (p == NULL)
+ return (NULL);
+
+ p->activate_op = pcap_activate_pf;
+ return (p);
+}
+
+/*
+ * XXX - is there an error from pfopen() that means "no such device"?
+ * Is there one that means "that device doesn't support pf"?
+ */
+static int
+can_be_bound(const char *name _U_)
+{
+ return (1);
+}
+
+static int
+get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
+{
+ /*
+ * Nothing we can do other than mark loopback devices as "the
+ * connected/disconnected status doesn't apply".
+ *
+ * XXX - is there a way to find out whether an adapter has
+ * something plugged into it?
+ */
+ if (*flags & PCAP_IF_LOOPBACK) {
+ /*
+ * Loopback devices aren't wireless, and "connected"/
+ * "disconnected" doesn't apply to them.
+ */
+ *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
+ return (0);
+ }
return (0);
}
int
-pcap_setfilter(pcap_t *p, struct bpf_program *fp)
+pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
{
+ return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
+ get_if_flags));
+}
+
+static int
+pcap_setfilter_pf(pcap_t *p, struct bpf_program *fp)
+{
+ struct pcap_pf *pf = p->priv;
+ struct bpf_version bv;
+
/*
- * See if BIOCSETF works. If it does, the kernel supports
- * BPF-style filters, and we do not need to do post-filtering.
+ * See if BIOCVERSION works. If not, we assume the kernel doesn't
+ * support BPF-style filters (it's not documented in the bpf(7)
+ * or packetfiler(7) man pages, but the code used to fail if
+ * BIOCSETF worked but BIOCVERSION didn't, and I've seen it do
+ * kernel filtering in DU 4.0, so presumably BIOCVERSION works
+ * there, at least).
*/
- p->md.use_bpf = (ioctl(p->fd, BIOCSETF, (caddr_t)fp) >= 0);
- if (p->md.use_bpf) {
- struct bpf_version bv;
+ if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) >= 0) {
+ /*
+ * OK, we have the version of the BPF interpreter;
+ * is it the same major version as us, and the same
+ * or better minor version?
+ */
+ if (bv.bv_major == BPF_MAJOR_VERSION &&
+ bv.bv_minor >= BPF_MINOR_VERSION) {
+ /*
+ * Yes. Try to install the filter.
+ */
+ if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) {
+ pcap_fmt_errmsg_for_errno(p->errbuf,
+ sizeof(p->errbuf), errno, "BIOCSETF");
+ return (-1);
+ }
- if (ioctl(p->fd, BIOCVERSION, (caddr_t)&bv) < 0) {
- snprintf(p->errbuf, sizeof(p->errbuf),
- "BIOCVERSION: %s", pcap_strerror(errno));
- return (-1);
- }
- else if (bv.bv_major != BPF_MAJOR_VERSION ||
- bv.bv_minor < BPF_MINOR_VERSION) {
- fprintf(stderr,
- "requires bpf language %d.%d or higher; kernel is %d.%d",
- BPF_MAJOR_VERSION, BPF_MINOR_VERSION,
- bv.bv_major, bv.bv_minor);
- /* don't give up, just be inefficient */
- p->md.use_bpf = 0;
+ /*
+ * OK, that succeeded. We're doing filtering in
+ * the kernel. (We assume we don't have a
+ * userland filter installed - that'd require
+ * a previous version check to have failed but
+ * this one to succeed.)
+ *
+ * XXX - this message should be supplied to the
+ * application as a warning of some sort,
+ * except that if it's a GUI application, it's
+ * not clear that it should be displayed in
+ * a window to annoy the user.
+ */
+ fprintf(stderr, "tcpdump: Using kernel BPF filter\n");
+ pf->filtering_in_kernel = 1;
+
+ /*
+ * Discard any previously-received packets,
+ * as they might have passed whatever filter
+ * was formerly in effect, but might not pass
+ * this filter (BIOCSETF discards packets buffered
+ * in the kernel, so you can lose packets in any
+ * case).
+ */
+ p->cc = 0;
+ return (0);
}
- } else {
- if (install_bpf_program(p, fp) < 0)
- return (-1);
+
+ /*
+ * We can't use the kernel's BPF interpreter; don't give
+ * up, just log a message and be inefficient.
+ *
+ * XXX - this should really be supplied to the application
+ * as a warning of some sort.
+ */
+ fprintf(stderr,
+ "tcpdump: Requires BPF language %d.%d or higher; kernel is %d.%d\n",
+ BPF_MAJOR_VERSION, BPF_MINOR_VERSION,
+ bv.bv_major, bv.bv_minor);
}
- /*XXX this goes in tcpdump*/
- if (p->md.use_bpf)
- fprintf(stderr, "tcpdump: Using kernel BPF filter\n");
- else
- fprintf(stderr, "tcpdump: Filtering in user process\n");
+ /*
+ * We couldn't do filtering in the kernel; do it in userland.
+ */
+ if (install_bpf_program(p, fp) < 0)
+ return (-1);
+
+ /*
+ * XXX - this message should be supplied by the application as
+ * a warning of some sort.
+ */
+ fprintf(stderr, "tcpdump: Filtering in user process\n");
+ pf->filtering_in_kernel = 0;
return (0);
}
+
+/*
+ * Libpcap version string.
+ */
+const char *
+pcap_lib_version(void)
+{
+ return (PCAP_VERSION_STRING);
+}
projects / libpcap / blobdiff