proto_tcp.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009, 2010 Daniel Borkmann.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdint.h>
  10 #include <endian.h>
  11 #include <netinet/in.h>    /* for ntohs() */
  12 #include <asm/byteorder.h>
  13
  14 #include "proto.h"
  15 #include "protos.h"
  16 #include "dissector_eth.h"
  17 #include "built_in.h"
  18 #include "pkt_buff.h"
  19
  20 struct tcphdr {
  21         uint16_t source;
  22         uint16_t dest;
  23         uint32_t seq;
  24         uint32_t ack_seq;
  25 #if defined(__LITTLE_ENDIAN_BITFIELD)
  26         __extension__ uint16_t res1:4,
  27                                doff:4,
  28                                fin:1,
  29                                syn:1,
  30                                rst:1,
  31                                psh:1,
  32                                ack:1,
  33                                urg:1,
  34                                ece:1,
  35                                cwr:1;
  36 #elif defined(__BIG_ENDIAN_BITFIELD)
  37         __extension__ uint16_t doff:4,
  38                                res1:4,
  39                                cwr:1,
  40                                ece:1,
  41                                urg:1,
  42                                ack:1,
  43                                psh:1,
  44                                rst:1,
  45                                syn:1,
  46                                fin:1;
  47 #else
  48 # error  "Adjust your <asm/byteorder.h> defines"
  49 #endif
  50         uint16_t window;
  51         uint16_t check;
  52         uint16_t urg_ptr;
  53 } __attribute__((packed));
  54
  55 static void tcp(struct pkt_buff *pkt)
  56 {
  57         struct tcphdr *tcp = (struct tcphdr *) pkt_pull(pkt, sizeof(*tcp));
  58         uint16_t src, dest;
  59         char *src_name, *dest_name;
  60
  61         if (tcp == NULL)
  62                 return;
  63
  64         src = ntohs(tcp->source);
  65         dest = ntohs(tcp->dest);
  66
  67         src_name = lookup_port_tcp(src);
  68         dest_name = lookup_port_tcp(dest);
  69
  70         tprintf(" [ TCP ");
  71         tprintf("Port (%u", src);
  72         if (src_name)
  73                 tprintf(" (%s%s%s)", colorize_start(bold), src_name,
  74                         colorize_end());
  75         tprintf(" => %u", dest);
  76         if (dest_name)
  77                 tprintf(" (%s%s%s)", colorize_start(bold), dest_name,
  78                         colorize_end());
  79         tprintf("), ");
  80         tprintf("SN (0x%x), ", ntohl(tcp->seq));
  81         tprintf("AN (0x%x), ", ntohl(tcp->ack_seq));
  82         tprintf("DataOff (%u), ", tcp->doff);
  83         tprintf("Res (%u), ", tcp->res1);
  84         tprintf("Flags (");
  85         if (tcp->fin)
  86                 tprintf("FIN ");
  87         if (tcp->syn)
  88                 tprintf("SYN ");
  89         if (tcp->rst)
  90                 tprintf("RST ");
  91         if (tcp->psh)
  92                 tprintf("PSH ");
  93         if (tcp->ack)
  94                 tprintf("ACK ");
  95         if (tcp->urg)
  96                 tprintf("URG ");
  97         if (tcp->ece)
  98                 tprintf("ECE ");
  99         if (tcp->cwr)
 100                 tprintf("CWR ");
 101         tprintf("), ");
 102         tprintf("Window (%u), ", ntohs(tcp->window));
 103         tprintf("CSum (0x%.4x), ", ntohs(tcp->check));
 104         tprintf("UrgPtr (%u)", ntohs(tcp->urg_ptr));
 105         tprintf(" ]\n");
 106 }
 107
 108 static void tcp_less(struct pkt_buff *pkt)
 109 {
 110         struct tcphdr *tcp = (struct tcphdr *) pkt_pull(pkt, sizeof(*tcp));
 111         uint16_t src, dest;
 112         char *src_name, *dest_name;
 113
 114         if (tcp == NULL)
 115                 return;
 116
 117         src = ntohs(tcp->source);
 118         dest = ntohs(tcp->dest);
 119
 120         src_name = lookup_port_tcp(src);
 121         dest_name = lookup_port_tcp(dest);
 122
 123         tprintf(" TCP %u", src);
 124         if(src_name)
 125                 tprintf("(%s%s%s)", colorize_start(bold), src_name,
 126                         colorize_end());
 127         tprintf("/%u", dest);
 128         if(dest_name)
 129                 tprintf("(%s%s%s)", colorize_start(bold), dest_name,
 130                         colorize_end());
 131         tprintf(" F%s",colorize_start(bold));
 132         if (tcp->fin)
 133                 tprintf(" FIN");
 134         if (tcp->syn)
 135                 tprintf(" SYN");
 136         if (tcp->rst)
 137                 tprintf(" RST");
 138         if (tcp->psh)
 139                 tprintf(" PSH");
 140         if (tcp->ack)
 141                 tprintf(" ACK");
 142         if (tcp->urg)
 143                 tprintf(" URG");
 144         if (tcp->ece)
 145                 tprintf(" ECE");
 146         if (tcp->cwr)
 147                 tprintf(" CWR");
 148         tprintf("%s Win %u S/A 0x%x/0x%x", colorize_end(),
 149                 ntohs(tcp->window), ntohl(tcp->seq), ntohl(tcp->ack_seq));
 150 }
 151
 152 struct protocol tcp_ops = {
 153         .key = 0x06,
 154         .print_full = tcp,
 155         .print_less = tcp_less,
 156 };