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