proto_tcp.c

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