--- /dev/null
+/*
+ * Copyright (c) 2011 Jakub Zawadzki
+ * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 COPYRIGHT
+ * OWNER OR CONTRIBUTORS 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "pcap-int.h"
+
+#ifdef NEED_STRERROR_H
+#include "strerror.h"
+#endif
+
+#include <errno.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+
+#include <time.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <linux/types.h>
+
+#include <linux/netlink.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_log.h>
+
+#define HDR_LENGTH (NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct nfgenmsg))))
+
+#define NFLOG_IFACE "nflog"
+
+static int
+nflog_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
+{
+ const unsigned char *buf;
+ 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));
+
+ if (len < 0) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Can't receive packet %d:%s", errno, pcap_strerror(errno));
+ return -1;
+ }
+
+ buf = handle->buffer;
+ while (len >= NLMSG_SPACE(0)) {
+ const struct nlmsghdr *nlh = (const struct nlmsghdr *) buf;
+ u_int32_t msg_len;
+
+ 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);
+ return -1;
+ }
+
+ if (NFNL_SUBSYS_ID(nlh->nlmsg_type) == NFNL_SUBSYS_ULOG &&
+ NFNL_MSG_TYPE(nlh->nlmsg_type) == NFULNL_MSG_PACKET)
+ {
+ const struct nfattr *payload_attr = NULL;
+
+ if (nlh->nlmsg_len < HDR_LENGTH) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "Malformed message: (nlmsg_len: %u)", nlh->nlmsg_len);
+ return -1;
+ }
+
+ if (nlh->nlmsg_len > HDR_LENGTH) {
+ struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
+ int attr_len = nlh->nlmsg_len - NLMSG_ALIGN(HDR_LENGTH);
+
+ while (NFA_OK(attr, attr_len)) {
+ switch (NFA_TYPE(attr)) {
+ case NFULA_PAYLOAD:
+ payload_attr = attr;
+ break;
+ }
+ attr = NFA_NEXT(attr, attr_len);
+ }
+ }
+
+ if (payload_attr) {
+ struct pcap_pkthdr pkth;
+
+ const unsigned char *payload = NFA_DATA(payload_attr);
+ int payload_len = NFA_PAYLOAD(payload_attr);
+
+ pkth.len = pkth.caplen = payload_len;
+ /* pkth.caplen = min (payload_len, handle->snapshot); */
+
+ gettimeofday(&pkth.ts, NULL);
+ if (handle->fcode.bf_insns == NULL ||
+ bpf_filter(handle->fcode.bf_insns, payload, pkth.len, pkth.caplen))
+ {
+ handle->md.packets_read++;
+ callback(user, &pkth, payload);
+ count++;
+ }
+ }
+ }
+
+ msg_len = NLMSG_ALIGN(nlh->nlmsg_len);
+ if (msg_len > len)
+ msg_len = len;
+
+ len -= msg_len;
+ buf += msg_len;
+ }
+ return count;
+}
+
+static int
+netfilter_stats_linux(pcap_t *handle, struct pcap_stat *stats)
+{
+ stats->ps_recv = handle->md.packets_read;
+ stats->ps_drop = 0;
+ stats->ps_ifdrop = 0;
+ return 0;
+}
+
+static int
+netfilter_inject_linux(pcap_t *handle, const void *buf, size_t size)
+{
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on netfilter devices");
+ return (-1);
+}
+
+struct my_nfattr {
+ u_int16_t nfa_len;
+ u_int16_t nfa_type;
+ void *data;
+};
+
+static int
+nflog_send_config_msg(const pcap_t *handle, u_int8_t family, u_int16_t res_id, const struct my_nfattr *mynfa)
+{
+ char buf[1024] __attribute__ ((aligned));
+
+ struct nlmsghdr *nlh = (struct nlmsghdr *) buf;
+ struct nfgenmsg *nfg = (struct nfgenmsg *) (buf + sizeof(struct nlmsghdr));
+
+ struct sockaddr_nl snl;
+ static unsigned int seq_id;
+
+ if (!seq_id)
+ seq_id = time(NULL);
+ ++seq_id;
+
+ nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nfgenmsg));
+ nlh->nlmsg_type = (NFNL_SUBSYS_ULOG << 8) | NFULNL_MSG_CONFIG;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+ nlh->nlmsg_pid = 0; /* to kernel */
+ nlh->nlmsg_seq = seq_id;
+
+ nfg->nfgen_family = family;
+ nfg->version = NFNETLINK_V0;
+ nfg->res_id = htons(res_id);
+
+ if (mynfa) {
+ struct nfattr *nfa = (struct nfattr *) (buf + NLMSG_ALIGN(nlh->nlmsg_len));
+
+ nfa->nfa_type = mynfa->nfa_type;
+ nfa->nfa_len = NFA_LENGTH(mynfa->nfa_len);
+ memcpy(NFA_DATA(nfa), mynfa->data, mynfa->nfa_len);
+ nlh->nlmsg_len = NLMSG_ALIGN(nlh->nlmsg_len) + NFA_ALIGN(nfa->nfa_len);
+ }
+
+ memset(&snl, 0, sizeof(snl));
+ snl.nl_family = AF_NETLINK;
+
+ if (sendto(handle->fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr *) &snl, sizeof(snl)) == -1)
+ return -1;
+
+ /* waiting for reply loop */
+ do {
+ socklen_t addrlen = sizeof(snl);
+ int len;
+
+ /* ignore interrupt system call error */
+ do {
+ len = recvfrom(handle->fd, buf, sizeof(buf), 0, (struct sockaddr *) &snl, &addrlen);
+ } while ((len == -1) && (errno == EINTR));
+
+ if (len <= 0)
+ return len;
+
+ if (addrlen != sizeof(snl) || snl.nl_family != AF_NETLINK) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ nlh = (struct nlmsghdr *) buf;
+ 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)) {
+ 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;
+ return -1;
+ }
+ errno = -(*((int *)NLMSG_DATA(nlh)));
+ return (errno == 0) ? 0 : -1;
+ }
+ nlh = NLMSG_NEXT(nlh, len);
+ }
+ } while (1);
+
+ return -1; /* never here */
+}
+
+static int
+nflog_send_config_cmd(const pcap_t *handle, u_int16_t group_id, u_int8_t cmd, u_int8_t family)
+{
+ struct nfulnl_msg_config_cmd msg;
+ struct my_nfattr nfa;
+
+ msg.command = cmd;
+
+ nfa.data = &msg;
+ nfa.nfa_type = NFULA_CFG_CMD;
+ nfa.nfa_len = sizeof(msg);
+
+ 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)
+{
+ struct nfulnl_msg_config_mode msg;
+ struct my_nfattr nfa;
+
+ msg.copy_range = htonl(copy_range);
+ msg.copy_mode = copy_mode;
+
+ nfa.data = &msg;
+ nfa.nfa_type = NFULA_CFG_MODE;
+ nfa.nfa_len = sizeof(msg);
+
+ return nflog_send_config_msg(handle, AF_UNSPEC, group_id, &nfa);
+}
+
+static int
+nflog_activate(pcap_t* handle)
+{
+ const char *dev = handle->opt.source;
+ unsigned short groups[32];
+ int group_count = 0;
+ int i;
+
+ if (strncmp(dev, NFLOG_IFACE, strlen(NFLOG_IFACE)) == 0) {
+ dev += strlen(NFLOG_IFACE);
+
+ /* nflog:30,33,42 looks nice, allow it */
+ if (*dev == ':')
+ dev++;
+
+ while (*dev) {
+ long int group_id;
+ char *end_dev;
+
+ if (group_count == 32) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Maximum 32 netfilter groups! dev: %s",
+ handle->opt.source);
+ return PCAP_ERROR;
+ }
+
+ group_id = strtol(dev, &end_dev, 0);
+ if (end_dev != dev) {
+ if (group_id < 0 || group_id > 65535) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Netfilter group range from 0 to 65535 (got %ld)",
+ group_id);
+ return PCAP_ERROR;
+ }
+
+ groups[group_count++] = (unsigned short) group_id;
+ dev = end_dev;
+ }
+ if (*dev != ',')
+ break;
+ dev++;
+ }
+ }
+
+ if (*dev) {
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Can't get netfilter group(s) index from %s",
+ handle->opt.source);
+ return PCAP_ERROR;
+ }
+
+ /* if no groups, add default: 0 */
+ if (!group_count) {
+ groups[0] = 0;
+ group_count = 1;
+ }
+
+ /* Initialize some components of the pcap structure. */
+ handle->bufsize = 128 + handle->snapshot;
+ handle->offset = 0;
+ handle->linktype = DLT_IPV4;
+ handle->read_op = nflog_read_linux;
+ handle->inject_op = netfilter_inject_linux;
+ handle->setfilter_op = install_bpf_program; /* no kernel filtering */
+ handle->setdirection_op = NULL;
+ handle->set_datalink_op = NULL;
+ handle->getnonblock_op = pcap_getnonblock_fd;
+ handle->setnonblock_op = pcap_setnonblock_fd;
+ handle->stats_op = netfilter_stats_linux;
+
+ /* 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));
+ 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));
+ goto close_fail;
+ }
+
+ 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));
+ 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));
+ 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));
+ 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));
+ goto close_fail;
+ }
+ }
+
+ if (handle->opt.rfmon) {
+ /*
+ * Monitor mode doesn't apply to netfilter devices.
+ */
+ pcap_cleanup_live_common(handle);
+ return PCAP_ERROR_RFMON_NOTSUP;
+ }
+
+ if (handle->opt.buffer_size != 0) {
+ /*
+ * 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));
+ goto close_fail;
+ }
+ }
+
+ handle->selectable_fd = handle->fd;
+ return 0;
+
+close_fail:
+ pcap_cleanup_live_common(handle);
+ return PCAP_ERROR;
+}
+
+pcap_t *
+nflog_create(const char *device, char *ebuf)
+{
+ pcap_t *p;
+
+ p = pcap_create_common(device, ebuf);
+ if (p == NULL)
+ return (NULL);
+
+ p->activate_op = nflog_activate;
+ return (p);
+}
+
+int
+netfilter_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
+{
+ pcap_if_t *found_dev = *alldevsp;
+ int sock;
+
+ sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);
+ if (sock < 0) {
+ /* if netlink is not supported this this is not fatal */
+ if (errno == EAFNOSUPPORT)
+ return 0;
+ snprintf(err_str, PCAP_ERRBUF_SIZE, "Can't open netlink socket %d:%s",
+ errno, pcap_strerror(errno));
+ return -1;
+ }
+ close(sock);
+
+ if (pcap_add_if(&found_dev, NFLOG_IFACE, 0, "Linux netfilter log (NFLOG) interface", err_str) < 0)
+ return -1;
+ return 0;
+}
+
projects / libpcap / commitdiff
