src/nf-queue.c

   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@trash.net>
  10  * Copyright (c) 2010  Karl Hiramoto <karl@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 }