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 <limits.h>
  10 #include <libnl3/netlink/msg.h>
  11 #include <libgen.h>
  12
  13 #include "pkt_buff.h"
  14 #include "proto.h"
  15 #include "protos.h"
  16
  17 static void nlmsg(struct pkt_buff *pkt)
  18 {
  19         struct nlmsghdr *hdr = (struct nlmsghdr *) pkt_pull(pkt, sizeof(*hdr));
  20         char type[32];
  21         char flags[128];
  22         char procname[PATH_MAX];
  23
  24         if (hdr == NULL)
  25                 return;
  26
  27         /* Look up the process name if message is not coming from the kernel.
  28          *
  29          * Note that the port id is not necessarily equal to the PID of the
  30          * receiving process (e.g. if the application is multithreaded or using
  31          * multiple sockets). In these cases we're not able to find a matching
  32          * PID and the information will not be printed.
  33          */
  34         if (hdr->nlmsg_pid != 0) {
  35                 char path[1024];
  36                 int ret;
  37
  38                 snprintf(path, sizeof(path), "/proc/%u/exe", hdr->nlmsg_pid);
  39                 ret = readlink(path, procname, sizeof(procname) - 1);
  40                 if (ret < 0)
  41                         ret = 0;
  42                 procname[ret] = '\0';
  43         } else
  44                 snprintf(procname, sizeof(procname), "kernel");
  45
  46         tprintf(" [ NLMSG ");
  47         tprintf("Len %u, ", hdr->nlmsg_len);
  48         tprintf("Type 0x%.4x (%s%s%s), ", hdr->nlmsg_type,
  49                 colorize_start(bold),
  50                 nl_nlmsgtype2str(hdr->nlmsg_type, type, sizeof(type)),
  51                 colorize_end());
  52         tprintf("Flags 0x%.4x (%s%s%s), ", hdr->nlmsg_flags,
  53                 colorize_start(bold),
  54                 nl_nlmsg_flags2str(hdr->nlmsg_flags, flags, sizeof(flags)),
  55                 colorize_end());
  56         tprintf("Seq-Nr %u, ", hdr->nlmsg_seq);
  57         tprintf("PID %u", hdr->nlmsg_pid);
  58         if (procname[0])
  59                 tprintf(" (%s%s%s)", colorize_start(bold), basename(procname),
  60                         colorize_end());
  61         tprintf(" ]\n");
  62 }
  63
  64 static void nlmsg_less(struct pkt_buff *pkt)
  65 {
  66         struct nlmsghdr *hdr = (struct nlmsghdr *) pkt_pull(pkt, sizeof(*hdr));
  67         char type[32];
  68
  69         if (hdr == NULL)
  70                 return;
  71
  72         tprintf(" NLMSG %u (%s%s%s)", hdr->nlmsg_type, colorize_start(bold),
  73                 nl_nlmsgtype2str(hdr->nlmsg_type, type, sizeof(type)),
  74                 colorize_end());
  75 }
  76
  77 struct protocol nlmsg_ops = {
  78         .print_full = nlmsg,
  79         .print_less = nlmsg_less,
  80 };