* 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
+ * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
*/
#ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
#endif
#include "pcap-int.h"
#include <linux/netfilter/nfnetlink_queue.h>
/* NOTE: if your program drops privilages after pcap_activate() it WON'T work with nfqueue.
- * It took me quite some time to debug ;/
+ * It took me quite some time to debug ;/
*
* Sending any data to nfnetlink socket requires CAP_NET_ADMIN privilages,
* and in nfqueue we need to send verdict reply after recving packet.
*
* In tcpdump you can disable dropping privilages with -Z root
*/
-
+
#include "pcap-netfilter-linux.h"
#define HDR_LENGTH (NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg))))
*/
struct pcap_netfilter {
u_int packets_read; /* count of packets read with recvfrom() */
+ u_int packets_nobufs; /* ENOBUFS counter */
};
-static int nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict);
+static int nfqueue_send_verdict(const pcap_t *handle, uint16_t group_id, u_int32_t id, u_int32_t verdict);
+
static int
netfilter_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
{
struct pcap_netfilter *handlep = handle->priv;
- const unsigned char *buf;
+ register u_char *bp, *ep;
int count = 0;
- int len;
-
- /* ignore interrupt system call error */
- do {
- len = recv(handle->fd, handle->buffer, handle->bufsize, 0);
- if (handle->break_loop) {
- handle->break_loop = 0;
- return -2;
- }
- } while ((len == -1) && (errno == EINTR));
+ ssize_t len;
- if (len < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", errno, pcap_strerror(errno));
- return -1;
+ /*
+ * Has "pcap_breakloop()" been called?
+ */
+ if (handle->break_loop) {
+ /*
+ * Yes - clear the flag that indicates that it
+ * has, and return PCAP_ERROR_BREAK to indicate
+ * that we were told to break out of the loop.
+ */
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
}
+ len = handle->cc;
+ if (len == 0) {
+ /*
+ * The buffer is empty; refill it.
+ *
+ * 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).
+ */
+ do {
+ len = recv(handle->fd, handle->buffer, handle->bufsize, 0);
+ if (handle->break_loop) {
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
+ }
+ if (errno == ENOBUFS)
+ handlep->packets_nobufs++;
+ } while ((len == -1) && (errno == EINTR || errno == ENOBUFS));
+
+ if (len < 0) {
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno, "Can't receive packet");
+ return PCAP_ERROR;
+ }
- buf = handle->buffer;
- while (len >= NLMSG_SPACE(0)) {
- const struct nlmsghdr *nlh = (const struct nlmsghdr *) buf;
- u_int32_t msg_len;
+ bp = (unsigned char *)handle->buffer;
+ } else
+ bp = handle->bp;
+ ep = bp + len;
+ while (bp < ep) {
+ const struct nlmsghdr *nlh = (const struct nlmsghdr *) bp;
+ uint32_t msg_len;
nftype_t type = OTHER;
+ /*
+ * Has "pcap_breakloop()" been called?
+ * If so, return immediately - if we haven't read any
+ * packets, clear the flag and return PCAP_ERROR_BREAK
+ * 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 (handle->break_loop) {
+ handle->bp = bp;
+ handle->cc = (int)(ep - bp);
+ if (count == 0) {
+ handle->break_loop = 0;
+ return PCAP_ERROR_BREAK;
+ } else
+ return count;
+ }
+ if (ep - bp < NLMSG_SPACE(0)) {
+ /*
+ * There's less than one netlink message left
+ * in the buffer. Give up.
+ */
+ break;
+ }
- if (nlh->nlmsg_len < sizeof(struct nlmsghdr) || len < nlh->nlmsg_len) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Message truncated: (got: %d) (nlmsg_len: %u)", len, nlh->nlmsg_len);
+ if (nlh->nlmsg_len < sizeof(struct nlmsghdr) || (u_int)len < nlh->nlmsg_len) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Message truncated: (got: %zd) (nlmsg_len: %u)", len, nlh->nlmsg_len);
return -1;
}
- if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG &&
- NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET)
+ if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG &&
+ NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET)
type = NFLOG;
- else if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_QUEUE &&
+ else if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_QUEUE &&
NFNL_MSG_TYPE(nlh->nlmsg_type) == NFQNL_MSG_PACKET)
type = NFQUEUE;
const unsigned char *payload = NULL;
struct pcap_pkthdr pkth;
- const struct nfgenmsg *nfg;
+ const struct nfgenmsg *nfg = NULL;
int id = 0;
if (handle->linktype != DLT_NFLOG) {
gettimeofday(&pkth.ts, NULL);
if (handle->fcode.bf_insns == NULL ||
- bpf_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen))
+ pcap_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen))
{
handlep->packets_read++;
callback(user, &pkth, payload);
if (type == NFQUEUE) {
/* XXX, possible responses: NF_DROP, NF_ACCEPT, NF_STOLEN, NF_QUEUE, NF_REPEAT, NF_STOP */
- nfqueue_send_verdict(handle, ntohs(nfg->res_id), id, NF_ACCEPT);
+ /* if type == NFQUEUE, handle->linktype is always != DLT_NFLOG,
+ so nfg is always initialized to NLMSG_DATA(nlh). */
+ if (nfg != NULL)
+ nfqueue_send_verdict(handle, ntohs(nfg->res_id), id, NF_ACCEPT);
}
}
msg_len = NLMSG_ALIGN(nlh->nlmsg_len);
- if (msg_len > len)
- msg_len = len;
-
- len -= msg_len;
- buf += msg_len;
+ /*
+ * If the message length would run past the end of the
+ * buffer, truncate it to the remaining space in the
+ * buffer.
+ */
+ if (msg_len > ep - bp)
+ msg_len = (uint32_t)(ep - bp);
+
+ bp += msg_len;
+ if (count >= max_packets && !PACKET_COUNT_IS_UNLIMITED(max_packets)) {
+ handle->bp = bp;
+ handle->cc = (int)(ep - bp);
+ if (handle->cc < 0)
+ handle->cc = 0;
+ return count;
+ }
}
+
+ handle->cc = 0;
return count;
}
struct pcap_netfilter *handlep = handle->priv;
stats->ps_recv = handlep->packets_read;
- stats->ps_drop = 0;
+ stats->ps_drop = handlep->packets_nobufs;
stats->ps_ifdrop = 0;
return 0;
}
static int
-netfilter_inject_linux(pcap_t *handle, const void *buf, size_t size)
+netfilter_inject_linux(pcap_t *handle, const void *buf _U_, int size _U_)
{
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on netfilter devices");
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Packet injection is not supported on netfilter devices");
return (-1);
-}
+}
struct my_nfattr {
- u_int16_t nfa_len;
- u_int16_t nfa_type;
+ uint16_t nfa_len;
+ uint16_t nfa_type;
void *data;
};
static int
-netfilter_send_config_msg(const pcap_t *handle, u_int16_t msg_type, int ack, u_int8_t family, u_int16_t res_id, const struct my_nfattr *mynfa)
+netfilter_send_config_msg(const pcap_t *handle, uint16_t msg_type, int ack, u_int8_t family, u_int16_t res_id, const struct my_nfattr *mynfa)
{
char buf[1024] __attribute__ ((aligned));
struct sockaddr_nl snl;
static unsigned int seq_id;
-
+
if (!seq_id)
seq_id = time(NULL);
++seq_id;
/* ignore interrupt system call error */
do {
- len = recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen);
+ /*
+ * The buffer is not so big that its size won't
+ * fit into an int.
+ */
+ len = (int)recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen);
} while ((len == -1) && (errno == EINTR));
if (len <= 0)
if (snl.nl_pid != 0 || seq_id != nlh->nlmsg_seq) /* if not from kernel or wrong sequence skip */
continue;
- while (len >= NLMSG_SPACE(0) && NLMSG_OK(nlh, len)) {
+ while ((u_int)len >= NLMSG_SPACE(0) && NLMSG_OK(nlh, (u_int)len)) {
if (nlh->nlmsg_type == NLMSG_ERROR || (nlh->nlmsg_type == NLMSG_DONE && nlh->nlmsg_flags & NLM_F_MULTI)) {
if (nlh->nlmsg_len < NLMSG_ALIGN(sizeof(struct nlmsgerr))) {
errno = EBADMSG;
}
static int
-nflog_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)
+nflog_send_config_msg(const pcap_t *handle, uint8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)
{
return netfilter_send_config_msg(handle, (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG, 1, family, group_id, mynfa);
}
static int
-nflog_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int8_t family)
+nflog_send_config_cmd(const pcap_t *handle, uint16_t group_id, u_int8_t cmd, u_int8_t family)
{
struct nfulnl_msg_config_cmd msg;
struct my_nfattr nfa;
return nflog_send_config_msg(handle, family, group_id, &nfa);
}
-static int
-nflog_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)
+static int
+nflog_send_config_mode(const pcap_t *handle, uint16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)
{
struct nfulnl_msg_config_mode msg;
struct my_nfattr nfa;
}
static int
-nfqueue_send_verdict(const pcap_t *handle, u_int16_t group_id, u_int32_t id, u_int32_t verdict)
+nfqueue_send_verdict(const pcap_t *handle, uint16_t group_id, u_int32_t id, u_int32_t verdict)
{
struct nfqnl_msg_verdict_hdr msg;
struct my_nfattr nfa;
}
static int
-nfqueue_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)
+nfqueue_send_config_msg(const pcap_t *handle, uint8_t family, u_int16_t group_id, const struct my_nfattr *mynfa)
{
return netfilter_send_config_msg(handle, (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG, 1, family, group_id, mynfa);
}
static int
-nfqueue_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int16_t pf)
+nfqueue_send_config_cmd(const pcap_t *handle, uint16_t group_id, u_int8_t cmd, u_int16_t pf)
{
struct nfqnl_msg_config_cmd msg;
struct my_nfattr nfa;
return nfqueue_send_config_msg(handle, AF_UNSPEC, group_id, &nfa);
}
-static int
-nfqueue_send_config_mode(const pcap_t *handle, u_int16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)
+static int
+nfqueue_send_config_mode(const pcap_t *handle, uint16_t group_id, u_int8_t copy_mode, u_int32_t copy_range)
{
struct nfqnl_msg_config_params msg;
struct my_nfattr nfa;
static int
netfilter_activate(pcap_t* handle)
{
- const char *dev = handle->opt.source;
+ const char *dev = handle->opt.device;
unsigned short groups[32];
int group_count = 0;
nftype_t type = OTHER;
dev += strlen(NFQUEUE_IFACE);
type = NFQUEUE;
}
-
+
if (type != OTHER && *dev == ':') {
dev++;
while (*dev) {
if (group_count == 32) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "Maximum 32 netfilter groups! dev: %s",
- handle->opt.source);
+ "Maximum 32 netfilter groups! dev: %s",
+ handle->opt.device);
return PCAP_ERROR;
}
if (type == OTHER || *dev) {
snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
- "Can't get netfilter group(s) index from %s",
- handle->opt.source);
+ "Can't get netfilter group(s) index from %s",
+ handle->opt.device);
return PCAP_ERROR;
}
group_count = 1;
}
+ /*
+ * 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 (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
+ handle->snapshot = MAXIMUM_SNAPLEN;
+
/* Initialize some components of the pcap structure. */
handle->bufsize = 128 + handle->snapshot;
handle->offset = 0;
/* Create netlink socket */
handle->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);
if (handle->fd < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't create raw socket %d:%s", errno, pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "Can't create raw socket");
return PCAP_ERROR;
}
handle->buffer = malloc(handle->bufsize);
if (!handle->buffer) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't allocate dump buffer: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
+ errno, "Can't allocate dump buffer");
goto close_fail;
}
if (type == NFLOG) {
if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno,
+ "NFULNL_CFG_CMD_PF_UNBIND");
goto close_fail;
}
if (nflog_send_config_cmd(handle, 0, NFULNL_CFG_CMD_PF_BIND, AF_INET) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno, "NFULNL_CFG_CMD_PF_BIND");
goto close_fail;
}
/* Bind socket to the nflog groups */
for (i = 0; i < group_count; i++) {
if (nflog_send_config_cmd(handle, groups[i], NFULNL_CFG_CMD_BIND, AF_UNSPEC) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno,
+ "Can't listen on group group index");
goto close_fail;
}
if (nflog_send_config_mode(handle, groups[i], NFULNL_COPY_PACKET, handle->snapshot) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFULNL_COPY_PACKET: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno,
+ "NFULNL_COPY_PACKET");
goto close_fail;
}
}
} else {
if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_UNBIND: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno, "NFQNL_CFG_CMD_PF_UNBIND");
goto close_fail;
}
if (nfqueue_send_config_cmd(handle, 0, NFQNL_CFG_CMD_PF_BIND, AF_INET) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_CFG_CMD_PF_BIND: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno, "NFQNL_CFG_CMD_PF_BIND");
goto close_fail;
}
/* Bind socket to the nfqueue groups */
for (i = 0; i < group_count; i++) {
if (nfqueue_send_config_cmd(handle, groups[i], NFQNL_CFG_CMD_BIND, AF_UNSPEC) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't listen on group group index: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno,
+ "Can't listen on group group index");
goto close_fail;
}
if (nfqueue_send_config_mode(handle, groups[i], NFQNL_COPY_PACKET, handle->snapshot) < 0) {
- snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "NFQNL_COPY_PACKET: %s", pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno,
+ "NFQNL_COPY_PACKET");
goto close_fail;
}
}
* Set the socket buffer size to the specified value.
*/
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));
+ pcap_fmt_errmsg_for_errno(handle->errbuf,
+ PCAP_ERRBUF_SIZE, errno, "SO_RCVBUF");
goto close_fail;
}
}
/* Does it begin with NFLOG_IFACE or NFQUEUE_IFACE? */
if (strncmp(cp, NFLOG_IFACE, sizeof NFLOG_IFACE - 1) == 0)
cp += sizeof NFLOG_IFACE - 1;
- else if (strncmp(cp, NFQUEUE_IFACE, sizeof NFQUEUE_IFACE - 1) == 0)
+ else if (strncmp(cp, NFQUEUE_IFACE, sizeof NFQUEUE_IFACE - 1) == 0)
cp += sizeof NFQUEUE_IFACE - 1;
else {
/* Nope, doesn't begin with NFLOG_IFACE nor NFQUEUE_IFACE */
/* OK, it's probably ours. */
*is_ours = 1;
- p = pcap_create_common(device, ebuf, sizeof (struct pcap_netfilter));
+ p = pcap_create_common(ebuf, sizeof (struct pcap_netfilter));
if (p == NULL)
return (NULL);
return (p);
}
-int
-netfilter_findalldevs(pcap_if_t **alldevsp, char *err_str)
+int
+netfilter_findalldevs(pcap_if_list_t *devlistp, char *err_str)
{
int sock;
-
+
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);
if (sock < 0) {
/* if netlink is not supported this is not fatal */
if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT)
return 0;
- snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't open netlink socket %d:%s",
- errno, pcap_strerror(errno));
+ pcap_fmt_errmsg_for_errno(err_str, PCAP_ERRBUF_SIZE,
+ errno, "Can't open netlink socket");
return -1;
}
close(sock);
- if (pcap_add_if(alldevsp, NFLOG_IFACE, 0, "Linux netfilter log (NFLOG) interface", err_str) < 0)
+ /*
+ * The notion of "connected" vs. "disconnected" doesn't apply.
+ * XXX - what about "up" and "running"?
+ */
+ if (add_dev(devlistp, NFLOG_IFACE,
+ PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
+ "Linux netfilter log (NFLOG) interface", err_str) == NULL)
return -1;
- if (pcap_add_if(alldevsp, NFQUEUE_IFACE, 0, "Linux netfilter queue (NFQUEUE) interface", err_str) < 0)
+ if (add_dev(devlistp, NFQUEUE_IFACE,
+ PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
+ "Linux netfilter queue (NFQUEUE) interface", err_str) == NULL)
return -1;
return 0;
}
projects / libpcap / blobdiff