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      1 /*
      2  * src/nf-queue.c     Monitor netfilter queue events
      3  *
      4  *	This library is free software; you can redistribute it and/or
      5  *	modify it under the terms of the GNU Lesser General Public
      6  *	License as published by the Free Software Foundation version 2.1
      7  *	of the License.
      8  *
      9  * Copyright (c) 2007, 2008 Patrick McHardy <kaber (at) trash.net>
     10  * Copyright (c) 2010  Karl Hiramoto <karl (at) hiramoto.org>
     11  */
     12 
     13 
     14 #include <netlink/cli/utils.h>
     15 #include <netlink/cli/link.h>
     16 #include <linux/netfilter.h>
     17 #include <linux/netfilter/nfnetlink_queue.h>
     18 #include <netlink/netfilter/nfnl.h>
     19 #include <netlink/netfilter/queue.h>
     20 #include <netlink/netfilter/queue_msg.h>
     21 
     22 static struct nl_sock *nf_sock;
     23 
     24 static struct nfnl_queue *alloc_queue(void)
     25 {
     26 	struct nfnl_queue *queue;
     27 
     28 	queue = nfnl_queue_alloc();
     29 	if (!queue)
     30 		nl_cli_fatal(ENOMEM, "Unable to allocate queue object");
     31 
     32 	return queue;
     33 }
     34 
     35 
     36 static void obj_input(struct nl_object *obj, void *arg)
     37 {
     38 	struct nfnl_queue_msg *msg = (struct nfnl_queue_msg *) obj;
     39 	struct nl_dump_params dp = {
     40 		.dp_type = NL_DUMP_STATS,
     41 		.dp_fd = stdout,
     42 		.dp_dump_msgtype = 1,
     43 	};
     44 	uint32_t packet_id = nfnl_queue_msg_get_packetid(msg);
     45 	static uint32_t next_packet_id = 0;
     46 	struct nfnl_queue_msg *lost_msg = NULL;
     47 	uint8_t family;
     48 	uint16_t group;
     49 
     50 	if (packet_id > next_packet_id) {
     51 		printf("Warning: %d Out of order packets.  Queue or socket overload \n", packet_id - next_packet_id);
     52 		group = nfnl_queue_msg_get_group(msg);
     53 		family = nfnl_queue_msg_get_family(msg);
     54 		lost_msg = nfnl_queue_msg_alloc();
     55 
     56 		do {
     57 			nfnl_queue_msg_set_group(lost_msg, group);
     58 			nfnl_queue_msg_set_family(lost_msg, family);
     59 			nfnl_queue_msg_set_packetid(lost_msg, next_packet_id);
     60 			nfnl_queue_msg_set_verdict(lost_msg, NF_ACCEPT);
     61 			nfnl_queue_msg_send_verdict(nf_sock, lost_msg);
     62 			next_packet_id++;
     63 		} while (packet_id > next_packet_id);
     64 
     65 		nfnl_queue_msg_put(lost_msg);
     66 	}
     67 
     68 	next_packet_id = packet_id + 1;
     69 	nfnl_queue_msg_set_verdict(msg, NF_ACCEPT);
     70 	nl_object_dump(obj, &dp);
     71 	nfnl_queue_msg_send_verdict(nf_sock, msg);
     72 }
     73 
     74 static int event_input(struct nl_msg *msg, void *arg)
     75 {
     76 	if (nl_msg_parse(msg, &obj_input, NULL) < 0)
     77 		fprintf(stderr, "<<EVENT>> Unknown message type\n");
     78 
     79 	/* Exit nl_recvmsgs_def() and return to the main select() */
     80 	return NL_STOP;
     81 }
     82 
     83 int main(int argc, char *argv[])
     84 {
     85 	struct nl_sock *rt_sock;
     86 	struct nl_cache *link_cache;
     87 	struct nfnl_queue *queue;
     88 	enum nfnl_queue_copy_mode copy_mode;
     89 	uint32_t copy_range;
     90 	int err = 1;
     91 	int family;
     92 
     93 	nf_sock = nfnl_queue_socket_alloc();
     94 	if (nf_sock == NULL)
     95 		nl_cli_fatal(ENOBUFS, "Unable to allocate netlink socket");
     96 
     97 	nl_socket_disable_seq_check(nf_sock);
     98 	nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
     99 
    100 	if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
    101 		printf("Usage: nf-queue family group [ copy_mode ] "
    102 		       "[ copy_range ]\n");
    103 		printf("family: [ inet | inet6 | ... ] \n");
    104 		printf("group: the --queue-num arg that you gave to iptables\n");
    105 		printf("copy_mode: [ none | meta | packet ] \n");
    106 		return 2;
    107 	}
    108 
    109 	nl_cli_connect(nf_sock, NETLINK_NETFILTER);
    110 
    111 	if ((family = nl_str2af(argv[1])) == AF_UNSPEC)
    112 		nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\"", argv[1]);
    113 
    114 	nfnl_queue_pf_unbind(nf_sock, family);
    115 	if ((err = nfnl_queue_pf_bind(nf_sock, family)) < 0)
    116 		nl_cli_fatal(err, "Unable to bind logger: %s",
    117 			     nl_geterror(err));
    118 
    119 	queue = alloc_queue();
    120 	nfnl_queue_set_group(queue, atoi(argv[2]));
    121 
    122 	copy_mode = NFNL_QUEUE_COPY_PACKET;
    123 	if (argc > 3) {
    124 		copy_mode = nfnl_queue_str2copy_mode(argv[3]);
    125 		if (copy_mode < 0)
    126 			nl_cli_fatal(copy_mode,
    127 				     "Unable to parse copy mode \"%s\": %s",
    128 				     argv[3], nl_geterror(copy_mode));
    129 	}
    130 	nfnl_queue_set_copy_mode(queue, copy_mode);
    131 
    132 	copy_range = 0xFFFF;
    133 	if (argc > 4)
    134 		copy_range = atoi(argv[4]);
    135 	nfnl_queue_set_copy_range(queue, copy_range);
    136 
    137 	if ((err = nfnl_queue_create(nf_sock, queue)) < 0)
    138 		nl_cli_fatal(err, "Unable to bind queue: %s", nl_geterror(err));
    139 
    140 	rt_sock = nl_cli_alloc_socket();
    141 	nl_cli_connect(rt_sock, NETLINK_ROUTE);
    142 	link_cache = nl_cli_link_alloc_cache(rt_sock);
    143 
    144 	nl_socket_set_buffer_size(nf_sock, 1024*127, 1024*127);
    145 
    146 	while (1) {
    147 		fd_set rfds;
    148 		int nffd, rtfd, maxfd, retval;
    149 
    150 		FD_ZERO(&rfds);
    151 
    152 		maxfd = nffd = nl_socket_get_fd(nf_sock);
    153 		FD_SET(nffd, &rfds);
    154 
    155 		rtfd = nl_socket_get_fd(rt_sock);
    156 		FD_SET(rtfd, &rfds);
    157 		if (maxfd < rtfd)
    158 			maxfd = rtfd;
    159 
    160 		/* wait for an incoming message on the netlink socket */
    161 		retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
    162 
    163 		if (retval) {
    164 			if (FD_ISSET(nffd, &rfds))
    165 				nl_recvmsgs_default(nf_sock);
    166 			if (FD_ISSET(rtfd, &rfds))
    167 				nl_recvmsgs_default(rt_sock);
    168 		}
    169 	}
    170 
    171 	return 0;
    172 }
    173