#include #include #include #include #include #include #include "xt_ipp2p.h" #include "compat_xtables.h" //#define IPP2P_DEBUG_ARES //#define IPP2P_DEBUG_SOUL //#define IPP2P_DEBUG_WINMX #define get_u8(X, O) (*(const __u8 *)((X) + O)) #define get_u16(X, O) get_unaligned((const __u16 *)((X) + O)) #define get_u32(X, O) get_unaligned((const __u32 *)((X) + O)) MODULE_AUTHOR("Eicke Friedrich/Klaus Degner "); MODULE_DESCRIPTION("An extension to iptables to identify P2P traffic."); MODULE_LICENSE("GPL"); /* Search for UDP eDonkey/eMule/Kad commands */ static unsigned int udp_search_edk(const unsigned char *t, const unsigned int packet_len) { if (packet_len < 4) return 0; switch (t[0]) { case 0xe3: /* edonkey */ switch (t[1]) { /* client -> server status request */ case 0x96: if (packet_len == 6) return IPP2P_EDK * 100 + 50; break; /* server -> client status request */ case 0x97: if (packet_len == 34) return IPP2P_EDK * 100 + 51; break; /* server description request */ /* e3 2a ff f0 .. | size == 6 */ case 0xa2: if (packet_len == 6 && get_u16(t, 2) == __constant_htons(0xfff0)) return IPP2P_EDK * 100 + 52; break; /* server description response */ /* e3 a3 ff f0 .. | size > 40 && size < 200 */ /* case 0xa3: return IPP2P_EDK * 100 + 53; break; */ case 0x9a: if (packet_len == 18) return IPP2P_EDK * 100 + 54; break; case 0x92: if (packet_len == 10) return IPP2P_EDK * 100 + 55; break; } break; case 0xe4: switch (t[1]) { /* e4 20 .. | size == 35 */ case 0x20: if (packet_len == 35 && t[2] != 0x00 && t[34] != 0x00) return IPP2P_EDK * 100 + 60; break; /* e4 00 .. 00 | size == 27 ? */ case 0x00: if (packet_len == 27 && t[26] == 0x00) return IPP2P_EDK * 100 + 61; break; /* e4 10 .. 00 | size == 27 ? */ case 0x10: if (packet_len == 27 && t[26] == 0x00) return IPP2P_EDK * 100 + 62; break; /* e4 18 .. 00 | size == 27 ? */ case 0x18: if (packet_len == 27 && t[26] == 0x00) return IPP2P_EDK * 100 + 63; break; /* e4 52 .. | size = 36 */ case 0x52: if (packet_len == 36) return IPP2P_EDK * 100 + 64; break; /* e4 58 .. | size == 6 */ case 0x58: if (packet_len == 6) return IPP2P_EDK * 100 + 65; break; /* e4 59 .. | size == 2 */ case 0x59: if (packet_len == 2) return IPP2P_EDK * 100 + 66; break; /* e4 28 .. | packet_len == 49,69,94,119... */ case 0x28: if ((packet_len - 44) % 25 == 0) return IPP2P_EDK * 100 + 67; break; /* e4 50 xx xx | size == 4 */ case 0x50: if (packet_len == 4) return IPP2P_EDK * 100 + 68; break; /* e4 40 xx xx | size == 48 */ case 0x40: if (packet_len == 48) return IPP2P_EDK * 100 + 69; break; } break; } return 0; } /* Search for UDP Gnutella commands */ static unsigned int udp_search_gnu(const unsigned char *t, const unsigned int packet_len) { if (packet_len >= 3 && memcmp(t, "GND", 3) == 0) return IPP2P_GNU * 100 + 51; if (packet_len >= 9 && memcmp(t, "GNUTELLA ", 9) == 0) return IPP2P_GNU * 100 + 52; return 0; } /* Search for UDP KaZaA commands */ static unsigned int udp_search_kazaa(const unsigned char *t, const unsigned int packet_len) { if (packet_len < 6) return 0; if (memcmp(t + packet_len - 6, "KaZaA\x00", 6) == 0) return IPP2P_KAZAA * 100 + 50; return 0; } /* Search for UDP DirectConnect commands */ static unsigned int udp_search_directconnect(const unsigned char *t, const unsigned int packet_len) { if (packet_len < 5) return 0; if (t[0] == 0x24 && t[packet_len-1] == 0x7c) { if (memcmp(&t[1], "SR ", 3) == 0) return IPP2P_DC * 100 + 60; if (packet_len >= 7 && memcmp(&t[1], "Ping ", 5) == 0) return IPP2P_DC * 100 + 61; } return 0; } /* Search for UDP BitTorrent commands */ static unsigned int udp_search_bit(const unsigned char *haystack, const unsigned int packet_len) { switch (packet_len) { case 16: /* ^ 00 00 04 17 27 10 19 80 */ if (ntohl(get_u32(haystack, 0)) == 0x00000417 && ntohl(get_u32(haystack, 4)) == 0x27101980) return IPP2P_BIT * 100 + 50; break; case 36: if (get_u32(haystack, 8) == __constant_htonl(0x00000400) && get_u32(haystack, 28) == __constant_htonl(0x00000104)) return IPP2P_BIT * 100 + 51; if (get_u32(haystack, 8) == __constant_htonl(0x00000400)) return IPP2P_BIT * 100 + 61; break; case 57: if (get_u32(haystack, 8) == __constant_htonl(0x00000404) && get_u32(haystack, 28) == __constant_htonl(0x00000104)) return IPP2P_BIT * 100 + 52; if (get_u32(haystack, 8) == __constant_htonl(0x00000404)) return IPP2P_BIT * 100 + 62; break; case 59: if (get_u32(haystack, 8) == __constant_htonl(0x00000406) && get_u32(haystack, 28) == __constant_htonl(0x00000104)) return (IPP2P_BIT * 100 + 53); if (get_u32(haystack, 8) == __constant_htonl(0x00000406)) return (IPP2P_BIT * 100 + 63); break; case 203: if (get_u32(haystack, 0) == __constant_htonl(0x00000405)) return IPP2P_BIT * 100 + 54; break; case 21: if (get_u32(haystack, 0) == __constant_htonl(0x00000401)) return IPP2P_BIT * 100 + 55; break; case 44: if (get_u32(haystack, 0) == __constant_htonl(0x00000827) && get_u32(haystack, 4) == __constant_htonl(0x37502950)) return IPP2P_BIT * 100 + 80; break; default: /* this packet does not have a constant size */ if (packet_len >= 32 && get_u32(haystack, 8) == __constant_htonl(0x00000402) && get_u32(haystack, 28) == __constant_htonl(0x00000104)) return IPP2P_BIT * 100 + 56; break; } /* some extra-bitcomet rules: "d1:" [a|r] "d2:id20:" */ if (packet_len > 22 && get_u8(haystack, 0) == 'd' && get_u8(haystack, 1) == '1' && get_u8(haystack, 2) == ':') if (get_u8(haystack, 3) == 'a' || get_u8(haystack, 3) == 'r') if (memcmp(haystack + 4, "d2:id20:", 8) == 0) return IPP2P_BIT * 100 + 57; #if 0 /* bitlord rules */ /* packetlen must be bigger than 32 */ /* first 4 bytes are zero */ if (packet_len > 32 && get_u32(haystack, 0) == 0x00000000) { /* first rule: 00 00 00 00 01 00 00 xx xx xx xx 00 00 00 00*/ if (get_u32(haystack, 4) == 0x00000000 && get_u32(haystack, 8) == 0x00010000 && get_u32(haystack, 16) == 0x00000000) return IPP2P_BIT * 100 + 71; /* 00 01 00 00 0d 00 00 xx xx xx xx 00 00 00 00*/ if (get_u32(haystack, 4) == 0x00000001 && get_u32(haystack, 8) == 0x000d0000 && get_u32(haystack, 16) == 0x00000000) return IPP2P_BIT * 100 + 71; } #endif return 0; } /* Search for Ares commands */ static unsigned int search_ares(const unsigned char *payload, const unsigned int plen) { if (plen < 3) return 0; /* all ares packets start with */ if (payload[1] == 0 && plen - payload[0] == 3) { switch (payload[2]) { case 0x5a: /* ares connect */ if (plen == 6 && payload[5] == 0x05) return IPP2P_ARES * 100 + 1; break; case 0x09: /* * ares search, min 3 chars --> 14 bytes * lets define a search can be up to 30 chars * --> max 34 bytes */ if (plen >= 14 && plen <= 34) return IPP2P_ARES * 100 + 1; break; #ifdef IPP2P_DEBUG_ARES default: printk(KERN_DEBUG "Unknown Ares command %x " "recognized, len: %u\n", (unsigned int)payload[2], plen); #endif } } #if 0 /* found connect packet: 03 00 5a 04 03 05 */ /* new version ares 1.8: 03 00 5a xx xx 05 */ if (plen == 6) /* possible connect command */ if (payload[0] == 0x03 && payload[1] == 0x00 && payload[2] == 0x5a && payload[5] == 0x05) return IPP2P_ARES * 100 + 1; if (plen == 60) /* possible download command*/ if (payload[59] == 0x0a && payload[58] == 0x0a) if (memcmp(t, "PUSH SHA1:", 10) == 0) /* found download command */ return IPP2P_ARES * 100 + 2; #endif return 0; } /* Search for SoulSeek commands */ static unsigned int search_soul(const unsigned char *payload, const unsigned int plen) { if (plen < 8) return 0; /* match: xx xx xx xx | xx = sizeof(payload) - 4 */ if (get_u32(payload, 0) == plen - 4) { const uint32_t m = get_u32(payload, 4); /* match 00 yy yy 00, yy can be everything */ if (get_u8(payload, 4) == 0x00 && get_u8(payload, 7) == 0x00) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "0: Soulseek command 0x%x " "recognized\n", get_u32(payload, 4)); #endif return IPP2P_SOUL * 100 + 1; } /* next match: 01 yy 00 00 | yy can be everything */ if (get_u8(payload, 4) == 0x01 && get_u16(payload, 6) == 0x0000) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "1: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 2; } /* other soulseek commandos are: 1-5,7,9,13-18,22,23,26,28,35-37,40-46,50,51,60,62-69,91,92,1001 */ /* try to do this in an intelligent way */ /* get all small commandos */ switch (m) { case 7: case 9: case 22: case 23: case 26: case 28: case 50: case 51: case 60: case 91: case 92: case 1001: #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "2: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 3; } if (m > 0 && m < 6) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "3: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 4; } if (m > 12 && m < 19) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "4: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 5; } if (m > 34 && m < 38) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "5: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 6; } if (m > 39 && m < 47) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "6: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 7; } if (m > 61 && m < 70) { #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "7: Soulseek command 0x%x " "recognized\n", get_u16(payload, 4)); #endif return IPP2P_SOUL * 100 + 8; } #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "unknown SOULSEEK command: 0x%x, first " "16 bit: 0x%x, first 8 bit: 0x%x ,soulseek ???\n", get_u32(payload, 4), get_u16(payload, 4) >> 16, get_u8(payload, 4) >> 24); #endif } /* match 14 00 00 00 01 yy 00 00 00 STRING(YY) 01 00 00 00 00 46|50 00 00 00 00 */ /* without size at the beginning !!! */ if (get_u32(payload, 0) == 0x14 && get_u8(payload, 4) == 0x01) { uint32_t y = get_u32(payload, 5); /* we need 19 chars + string */ if (y + 19 <= plen) { const unsigned char *w = payload + 9 + y; if (get_u32(w, 0) == 0x01 && (get_u16(w, 4) == 0x4600 || get_u16(w, 4) == 0x5000) && get_u32(w, 6) == 0x00) ; #ifdef IPP2P_DEBUG_SOUL printk(KERN_DEBUG "Soulssek special client command recognized\n"); #endif return IPP2P_SOUL * 100 + 9; } } return 0; } /* Search for WinMX commands */ static unsigned int search_winmx(const unsigned char *payload, const unsigned int plen) { if (plen == 4 && memcmp(payload, "SEND", 4) == 0) return IPP2P_WINMX * 100 + 1; if (plen == 3 && memcmp(payload, "GET", 3) == 0) return IPP2P_WINMX * 100 + 2; /* if (packet_len < head_len + 10) return 0; */ if (plen < 10) return 0; if (memcmp(payload, "SEND", 4) == 0 || memcmp(payload, "GET", 3) == 0) { uint16_t c = 4; const uint16_t end = plen - 2; uint8_t count = 0; while (c < end) { if (payload[c] == 0x20 && payload[c+1] == 0x22) { c++; count++; if (count >= 2) return IPP2P_WINMX * 100 + 3; } c++; } } if (plen == 149 && payload[0] == '8') { #ifdef IPP2P_DEBUG_WINMX printk(KERN_INFO "maybe WinMX\n"); #endif if (get_u32(payload, 17) == 0 && get_u32(payload, 21) == 0 && get_u32(payload, 25) == 0 && // get_u32(payload, 33) == __constant_htonl(0x71182b1a) && // get_u32(payload, 37) == __constant_htonl(0x05050000) && // get_u32(payload, 133) == __constant_htonl(0x31097edf) && // get_u32(payload, 145) == __constant_htonl(0xdcb8f792)) get_u16(payload, 39) == 0 && get_u16(payload, 135) == __constant_htons(0x7edf) && get_u16(payload,147) == __constant_htons(0xf792)) { #ifdef IPP2P_DEBUG_WINMX printk(KERN_INFO "got WinMX\n"); #endif return IPP2P_WINMX * 100 + 4; } } return 0; } /* Search for appleJuice commands */ static unsigned int search_apple(const unsigned char *payload, const unsigned int plen) { if (plen > 7 && payload[6] == 0x0d && payload[7] == 0x0a && memcmp(payload, "ajprot", 6) == 0) return IPP2P_APPLE * 100; return 0; } /* Search for BitTorrent commands */ static unsigned int search_bittorrent(const unsigned char *payload, const unsigned int plen) { if (plen > 20) { /* test for match 0x13+"BitTorrent protocol" */ if (payload[0] == 0x13) if (memcmp(payload + 1, "BitTorrent protocol", 19) == 0) return IPP2P_BIT * 100; /* * Any tracker command starts with GET / then *may be* some file on web server * (e.g. announce.php or dupa.pl or whatever.cgi or NOTHING for tracker on root dir) * but *must have* one (or more) of strings listed below (true for scrape and announce) */ if (memcmp(payload, "GET /", 5) == 0) { if (HX_memmem(payload, plen, "info_hash=", 10) != NULL) return IPP2P_BIT * 100 + 1; if (HX_memmem(payload, plen, "peer_id=", 8) != NULL) return IPP2P_BIT * 100 + 2; if (HX_memmem(payload, plen, "passkey=", 8) != NULL) return IPP2P_BIT * 100 + 4; } } else { /* bitcomet encryptes the first packet, so we have to detect another * one later in the flow */ /* first try failed, too many false positives */ /* if (size == 5 && get_u32(t, 0) == __constant_htonl(1) && t[4] < 3) return IPP2P_BIT * 100 + 3; */ /* second try: block request packets */ if (plen == 17 && get_u32(payload, 0) == __constant_htonl(0x0d) && payload[4] == 0x06 && get_u32(payload,13) == __constant_htonl(0x4000)) return IPP2P_BIT * 100 + 3; } return 0; } /* check for Kazaa get command */ static unsigned int search_kazaa(const unsigned char *payload, const unsigned int plen) { if (plen < 13) return 0; if (payload[plen-2] == 0x0d && payload[plen-1] == 0x0a && memcmp(payload, "GET /.hash=", 11) == 0) return IPP2P_DATA_KAZAA * 100; return 0; } /* check for gnutella get command */ static unsigned int search_gnu(const unsigned char *payload, const unsigned int plen) { if (plen < 11) return 0; if (payload[plen-2] == 0x0d && payload[plen-1] == 0x0a) { if (memcmp(payload, "GET /get/", 9) == 0) return IPP2P_DATA_GNU * 100 + 1; if (plen >= 15 && memcmp(payload, "GET /uri-res/", 13) == 0) return IPP2P_DATA_GNU * 100 + 2; } return 0; } /* check for gnutella get commands and other typical data */ static unsigned int search_all_gnu(const unsigned char *payload, const unsigned int plen) { if (plen < 11) return 0; if (payload[plen-2] == 0x0d && payload[plen-1] == 0x0a) { if (plen >= 19 && memcmp(payload, "GNUTELLA CONNECT/", 17) == 0) return IPP2P_GNU * 100 + 1; if (memcmp(payload, "GNUTELLA/", 9) == 0) return IPP2P_GNU * 100 + 2; if (plen >= 22 && (memcmp(payload, "GET /get/", 9) == 0 || memcmp(payload, "GET /uri-res/", 13) == 0)) { unsigned int c; for (c = 0; c < plen - 22; ++c) if (payload[c] == 0x0d && payload[c+1] == 0x0a && (memcmp(&payload[c+2], "X-Gnutella-", 11) == 0 || memcmp(&payload[c+2], "X-Queue:", 8) == 0)) return IPP2P_GNU * 100 + 3; } } return 0; } /* check for KaZaA download commands and other typical data */ /* plen is guaranteed to be >= 5 (see @matchlist) */ static unsigned int search_all_kazaa(const unsigned char *payload, const unsigned int plen) { uint16_t c, end, rem; if (plen < 7) /* too short for anything we test for - early bailout */ return 0; if (payload[plen-2] != 0x0d || payload[plen-1] != 0x0a) return 0; if (memcmp(payload, "GIVE ", 5) == 0) return IPP2P_KAZAA * 100 + 1; if (memcmp(payload, "GET /", 5) != 0) return 0; if (plen < 18) /* The next tests would not succeed anyhow. */ return 0; end = plen - 18; rem = plen - 5; for (c = 5; c < end; ++c, --rem) { if (payload[c] != 0x0d) continue; if (payload[c+1] != 0x0a) continue; if (rem >= 18 && memcmp(&payload[c+2], "X-Kazaa-Username: ", 18) == 0) return IPP2P_KAZAA * 100 + 2; if (rem >= 24 && memcmp(&payload[c+2], "User-Agent: PeerEnabler/", 24) == 0) return IPP2P_KAZAA * 100 + 2; } return 0; } /* fast check for edonkey file segment transfer command */ static unsigned int search_edk(const unsigned char *payload, const unsigned int plen) { if (plen < 6) return 0; if (payload[0] != 0xe3) { return 0; } else { if (payload[5] == 0x47) return IPP2P_DATA_EDK * 100; else return 0; } } /* intensive but slower search for some edonkey packets including size-check */ static unsigned int search_all_edk(const unsigned char *payload, const unsigned int plen) { if (plen < 6) return 0; if (payload[0] != 0xe3) { return 0; } else { unsigned int cmd = get_u16(payload, 1); if (cmd == plen - 5) { switch (payload[5]) { case 0x01: /* Client: hello or Server:hello */ return IPP2P_EDK * 100 + 1; case 0x4c: /* Client: Hello-Answer */ return IPP2P_EDK * 100 + 9; } } return 0; } } /* fast check for Direct Connect send command */ static unsigned int search_dc(const unsigned char *payload, const unsigned int plen) { if (plen < 6) return 0; if (payload[0] != 0x24) { return 0; } else { if (memcmp(&payload[1], "Send|", 5) == 0) return IPP2P_DATA_DC * 100; else return 0; } } /* intensive but slower check for all direct connect packets */ static unsigned int search_all_dc(const unsigned char *payload, const unsigned int plen) { if (plen < 7) return 0; if (payload[0] == 0x24 && payload[plen-1] == 0x7c) { const unsigned char *t = &payload[1]; /* Client-Hub-Protocol */ if (memcmp(t, "Lock ", 5) == 0) return IPP2P_DC * 100 + 1; /* * Client-Client-Protocol, some are already recognized by * client-hub (like lock) */ if (plen >= 9 && memcmp(t, "MyNick ", 7) == 0) return IPP2P_DC * 100 + 38; } return 0; } /* check for mute */ static unsigned int search_mute(const unsigned char *payload, const unsigned int plen) { if (plen == 209 || plen == 345 || plen == 473 || plen == 609 || plen == 1121) { //printk(KERN_DEBUG "size hit: %u", size); if (memcmp(payload,"PublicKey: ", 11) == 0) { return IPP2P_MUTE * 100 + 0; /* if (memcmp(t + size - 14, "\x0aEndPublicKey\x0a", 14) == 0) printk(KERN_DEBUG "end pubic key hit: %u", size); */ } } return 0; } /* check for xdcc */ static unsigned int search_xdcc(const unsigned char *payload, const unsigned int plen) { /* search in small packets only */ if (plen > 20 && plen < 200 && payload[plen-1] == 0x0a && payload[plen-2] == 0x0d && memcmp(payload, "PRIVMSG ", 8) == 0) { uint16_t x = 10; const uint16_t end = plen - 13; /* * is seems to be a irc private massage, chedck for * xdcc command */ while (x < end) { if (payload[x] == ':') if (memcmp(&payload[x+1], "xdcc send #", 11) == 0) return IPP2P_XDCC * 100 + 0; x++; } } return 0; } /* search for waste */ static unsigned int search_waste(const unsigned char *payload, const unsigned int plen) { if (plen >= 8 && memcmp(payload, "GET.sha1:", 9) == 0) return IPP2P_WASTE * 100 + 0; return 0; } static const struct { unsigned int command; unsigned int packet_len; unsigned int (*function_name)(const unsigned char *, const unsigned int); } matchlist[] = { {IPP2P_EDK, 20, search_all_edk}, {IPP2P_DATA_KAZAA, 200, search_kazaa}, /* exp */ {IPP2P_DATA_EDK, 60, search_edk}, /* exp */ {IPP2P_DATA_DC, 26, search_dc}, /* exp */ {IPP2P_DC, 5, search_all_dc}, {IPP2P_DATA_GNU, 40, search_gnu}, /* exp */ {IPP2P_GNU, 5, search_all_gnu}, {IPP2P_KAZAA, 5, search_all_kazaa}, {IPP2P_BIT, 20, search_bittorrent}, {IPP2P_APPLE, 5, search_apple}, {IPP2P_SOUL, 5, search_soul}, {IPP2P_WINMX, 2, search_winmx}, {IPP2P_ARES, 5, search_ares}, {IPP2P_MUTE, 200, search_mute}, {IPP2P_WASTE, 5, search_waste}, {IPP2P_XDCC, 5, search_xdcc}, {0}, }; static const struct { unsigned int command; unsigned int packet_len; unsigned int (*function_name)(const unsigned char *, const unsigned int); } udp_list[] = { {IPP2P_KAZAA, 14, udp_search_kazaa}, {IPP2P_BIT, 23, udp_search_bit}, {IPP2P_GNU, 11, udp_search_gnu}, {IPP2P_EDK, 9, udp_search_edk}, {IPP2P_DC, 12, udp_search_directconnect}, {0}, }; static bool ipp2p_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct ipt_p2p_info *info = par->matchinfo; const unsigned char *haystack; const struct iphdr *ip = ip_hdr(skb); bool p2p_result = false; int i = 0; unsigned int hlen = ntohs(ip->tot_len) - ip_hdrlen(skb); /* hlen = packet-data length */ /* must not be a fragment */ if (par->fragoff != 0) { if (info->debug) printk("IPP2P.match: offset found %d\n", par->fragoff); return 0; } /* make sure that skb is linear */ if (skb_is_nonlinear(skb)) { if (info->debug) printk("IPP2P.match: nonlinear skb found\n"); return 0; } haystack = skb_network_header(skb) + ip_hdrlen(skb); switch (ip->protocol) { case IPPROTO_TCP: /* what to do with a TCP packet */ { const struct tcphdr *tcph = (const void *)ip + ip_hdrlen(skb); if (tcph->fin) return 0; /* if FIN bit is set bail out */ if (tcph->syn) return 0; /* if SYN bit is set bail out */ if (tcph->rst) return 0; /* if RST bit is set bail out */ haystack += tcph->doff * 4; /* get TCP-Header-Size */ if (tcph->doff * 4 > hlen) { if (info->debug) pr_info("TCP header indicated packet larger than it is\n"); hlen = 0; } else { hlen -= tcph->doff * 4; } while (matchlist[i].command) { if ((info->cmd & matchlist[i].command) == matchlist[i].command && hlen > matchlist[i].packet_len) { p2p_result = matchlist[i].function_name(haystack, hlen); if (p2p_result) { if (info->debug) printk("IPP2P.debug:TCP-match: %i from: %u.%u.%u.%u:%i to: %u.%u.%u.%u:%i Length: %i\n", p2p_result, NIPQUAD(ip->saddr),ntohs(tcph->source), NIPQUAD(ip->daddr),ntohs(tcph->dest),hlen); return p2p_result; } } i++; } return p2p_result; } case IPPROTO_UDP: /* what to do with an UDP packet */ case IPPROTO_UDPLITE: { const struct udphdr *udph = (const void *)ip + ip_hdrlen(skb); haystack += sizeof(*udph); if (sizeof(*udph) > hlen) { if (info->debug) pr_info("UDP header indicated packet larger than it is\n"); hlen = 0; } else { hlen -= sizeof(*udph); } while (udp_list[i].command) { if ((info->cmd & udp_list[i].command) == udp_list[i].command && hlen > udp_list[i].packet_len) { p2p_result = udp_list[i].function_name(haystack, hlen); if (p2p_result) { if (info->debug) printk("IPP2P.debug:UDP-match: %i from: %u.%u.%u.%u:%i to: %u.%u.%u.%u:%i Length: %i\n", p2p_result, NIPQUAD(ip->saddr), ntohs(udph->source), NIPQUAD(ip->daddr), ntohs(udph->dest), hlen); return p2p_result; } } i++; } return p2p_result; } default: return 0; } } static struct xt_match ipp2p_mt_reg __read_mostly = { .name = "ipp2p", .revision = 1, .family = NFPROTO_IPV4, .match = ipp2p_mt, .matchsize = sizeof(struct ipt_p2p_info), .me = THIS_MODULE, }; static int __init ipp2p_mt_init(void) { return xt_register_match(&ipp2p_mt_reg); } static void __exit ipp2p_mt_exit(void) { xt_unregister_match(&ipp2p_mt_reg); } module_init(ipp2p_mt_init); module_exit(ipp2p_mt_exit); MODULE_ALIAS("ipt_ipp2p");