proto_nlmsg.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2014 Tobias Klauser.
   4  * Subject to the GPL, version 2.
   5  */
   6
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <libnl3/netlink/msg.h>
  10 #include <libgen.h>
  11
  12 #include "pkt_buff.h"
  13 #include "proto.h"
  14
  15 static void nlmsg(struct pkt_buff *pkt)
  16 {
  17         struct nlmsghdr *hdr = (struct nlmsghdr *) pkt_pull(pkt, sizeof(*hdr));
  18         char type[32];
  19         char flags[128];
  20         char procname[1024];
  21
  22         if (hdr == NULL)
  23                 return;
  24
  25         /* Look up the process name if message is not coming from the kernel.
  26          *
  27          * Note that the port id is not necessarily equal to the PID of the
  28          * receiving process (e.g. if the application is multithreaded or using
  29          * multiple sockets). In these cases we're not able to find a matching
  30          * PID and the information will not be printed.
  31          */
  32         if (hdr->nlmsg_pid != 0) {
  33                 char path[1024];
  34                 int ret;
  35
  36                 snprintf(path, sizeof(path), "/proc/%u/exe", hdr->nlmsg_pid);
  37                 ret = readlink(path, procname, sizeof(procname) - 1);
  38                 if (ret < 0)
  39                         procname[0] = '\0';
  40         } else
  41                 snprintf(procname, sizeof(procname), "kernel");
  42
  43         tprintf(" [ NLMSG ");
  44         tprintf("Len %u, ", hdr->nlmsg_len);
  45         tprintf("Type 0x%.4x (%s%s%s), ", hdr->nlmsg_type,
  46                 colorize_start(bold),
  47                 nl_nlmsgtype2str(hdr->nlmsg_type, type, sizeof(type)),
  48                 colorize_end());
  49         tprintf("Flags 0x%.4x (%s%s%s), ", hdr->nlmsg_flags,
  50                 colorize_start(bold),
  51                 nl_nlmsg_flags2str(hdr->nlmsg_flags, flags, sizeof(flags)),
  52                 colorize_end());
  53         tprintf("Seq-Nr %u, ", hdr->nlmsg_seq);
  54         tprintf("PID %u", hdr->nlmsg_pid);
  55         if (procname[0])
  56                 tprintf(" (%s%s%s)", colorize_start(bold), basename(procname),
  57                         colorize_end());
  58         tprintf(" ]\n");
  59 }
  60
  61 static void nlmsg_less(struct pkt_buff *pkt)
  62 {
  63         struct nlmsghdr *hdr = (struct nlmsghdr *) pkt_pull(pkt, sizeof(*hdr));
  64         char type[32];
  65
  66         if (hdr == NULL)
  67                 return;
  68
  69         tprintf(" NLMSG %u (%s%s%s)", hdr->nlmsg_type, colorize_start(bold),
  70                 nl_nlmsgtype2str(hdr->nlmsg_type, type, sizeof(type)),
  71                 colorize_end());
  72 }
  73
  74 struct protocol nlmsg_ops = {
  75         .print_full = nlmsg,
  76         .print_less = nlmsg_less,
  77 };