user/ferret/igmp.c

   1 /* Copyright (c) 2007 by Errata Security */\r
   2 #include "protos.h"\r
   3 #include "ferret.h"\r
   4 #include "netframe.h"\r
   5 #include "formats.h"\r
   6 \r
   7 \r
   8 static const char *group_name(struct NetFrame *frame, unsigned group_address)\r
   9 {\r
  10         switch (group_address) {\r
  11         case 0xeffffffa: return "SSDP"; break;\r
  12         case 0xe00000fb: return "mDNS"; break;\r
  13         case 0xe0000116: return "SLP (General)"; break;\r
  14         case 0xe0000123: return "SLP (Discovery)"; break;\r
  15         case 0xe4c8c8c9: return "(unknown)"; break;\r
  16         case 0xeffffffd: return "SLP (Admin Scoped)"; break;\r
  17         default: \r
  18                 FRAMERR(frame, "igmp: unknown group: %d.%d.%d.%d\n", \r
  19                         (group_address>>24)&0xFF,\r
  20                         (group_address>>16)&0xFF,\r
  21                         (group_address>> 8)&0xFF,\r
  22                         (group_address>> 0)&0xFF\r
  23                         );\r
  24                 return "(unknown)";\r
  25         }\r
  26 }\r
  27 void process_igmp(struct Seaper *seap, struct NetFrame *frame, const unsigned char *px, unsigned length)\r
  28 {\r
  29         struct {\r
  30                 unsigned version;\r
  31                 unsigned type;\r
  32                 unsigned max_resp_time;\r
  33                 unsigned checksum;\r
  34                 unsigned group_address;\r
  35         } igmp;\r
  36 \r
  37         if (length == 0) {\r
  38                 FRAMERR(frame, "igmp: frame empty\n");\r
  39                 return;\r
  40         }\r
  41         if (length < 8) {\r
  42                 FRAMERR(frame, "igmp: frame too short\n");\r
  43                 return;\r
  44         }\r
  45 \r
  46         igmp.type = px[0];\r
  47         igmp.max_resp_time = px[1];\r
  48         igmp.checksum = ex16be(px+2);\r
  49         igmp.group_address = ex32be(px+4);\r
  50 \r
  51         switch (igmp.type) {\r
  52         case 0x11: /* membership query */\r
  53                 break;\r
  54         case 0x16: /* membership report */\r
  55                 process_record(seap,\r
  56                         "proto",        REC_SZ,                 "IGMP",                         -1,\r
  57                         "op",           REC_SZ,                 "Membership",           -1,\r
  58                         "group",        REC_IPv4,               &igmp.group_address,    sizeof(igmp.group_address),\r
  59                         "groupname",REC_SZ,                     group_name(frame, igmp.group_address),  -1,\r
  60                         0);\r
  61                 break;\r
  62         case 0x17:\r
  63                 process_record(seap,\r
  64                         "proto",        REC_SZ,                 "IGMP",                         -1,\r
  65                         "op",           REC_SZ,                 "Membership",           -1,\r
  66                         "group",        REC_IPv4,               &igmp.group_address,    sizeof(igmp.group_address),\r
  67                         "groupname",REC_SZ,                     group_name(frame, igmp.group_address),  -1,\r
  68                         0);\r
  69                 break;\r
  70         case 0x22: /*v3 membersip report */\r
  71                 {\r
  72                         unsigned num_records = ex16be(px+6);\r
  73                         unsigned i;\r
  74                         unsigned offset=8;\r
  75 \r
  76                         if (num_records != 1) \r
  77                                 SAMPLE("igmp", "igmpv3.numrecs",        REC_UNSIGNED, &num_records,     sizeof(num_records));\r
  78 \r
  79                         for (i=0; i<num_records && offset+8 <= length; i++) {\r
  80                                 unsigned ip = ex32be(px+offset+4);\r
  81                                 unsigned sources = ex16be(px+offset+2);\r
  82                                 unsigned aux_data_len = px[offset+1]*4;\r
  83                                 process_record(seap,\r
  84                                         "proto",        REC_SZ,                 "IGMP",                         -1,\r
  85                                         "op",           REC_SZ,                 "Membership",           -1,\r
  86                                         "group",        REC_IPv4,               &ip,    sizeof(ip),\r
  87                                         "groupname",REC_SZ,                     group_name(frame, ip),  -1,\r
  88                                         0);\r
  89                                 offset += sources*4+aux_data_len+8;\r
  90                         }\r
  91                 }\r
  92                 break;\r
  93         default:\r
  94                 FRAMERR(frame, "igmp: unknown type=%d\n", igmp.type);\r
  95                 break;\r
  96         }\r
  97 }\r
  98 \r