218 lines
6.7 KiB
Text
218 lines
6.7 KiB
Text
$NetBSD: patch-aa,v 1.2 1998/08/07 11:10:57 agc Exp $
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*** sn_defines.h Fri Apr 18 11:33:58 1997
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--- sn_defines.h Thu Jul 24 16:02:16 1997
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***************
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*** 80,90 ****
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#define SYN 2
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#define FIN 1
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! #define NO_IP 0
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! #define NO_IP_4 1000
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! #define ICMP 1 /* Protocol Numbers */
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! #define TCP 6
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! #define UDP 17
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#define ICMP_HEADLENGTH 4 /* fixed ICMP header length */
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#define UDP_HEADLENGTH 8 /* fixed UDP header length */
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--- 80,91 ----
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#define SYN 2
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#define FIN 1
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! #define NO_IP 0
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! #define NO_IP_4 1000
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! #define CORRUPT_IP 1001
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! #define ICMP 1 /* Protocol Numbers */
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! #define TCP 6
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! #define UDP 17
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#define ICMP_HEADLENGTH 4 /* fixed ICMP header length */
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#define UDP_HEADLENGTH 8 /* fixed UDP header length */
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*** sn_packets.c Fri Apr 18 11:33:58 1997
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--- sn_packets.c Thu Aug 22 19:18:51 1985
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***************
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*** 43,48 ****
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--- 43,49 ----
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struct UDP_header UDPhead;
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int i;
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+ short int dummy; /* 2 bytes, important */
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memcpy(&IPhead,(sp+PROTO_HEAD),sizeof(struct IP_header));
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/* IP header Conversion */
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***************
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*** 51,56 ****
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--- 52,58 ----
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unwrapped->TCP_len = 0; /* Reset structure NEEDED!!! */
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unwrapped->UDP_len = 0;
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unwrapped->DATA_len = 0;
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+ unwrapped->FRAG_nf = 0;
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if(NO_CHKSUM == 0)
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{
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***************
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*** 75,106 ****
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/* restore orig buffer */
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/* general programming rule */
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}
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if(IPhead.protocol == TCP ) /* TCP */
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{
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! memcpy(&TCPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct TCP_header));
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! unwrapped->TCP_len = ntohs(TCPhead.offset_flag) & 0xF000;
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! unwrapped->TCP_len >>= 10;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->TCP_len);
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return TCP;
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}
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if(IPhead.protocol == ICMP ) /* ICMP */
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{
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! memcpy(&ICMPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct ICMP_header));
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! unwrapped->ICMP_len = ICMP_HEADLENGTH;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->ICMP_len);
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! return ICMP;
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}
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if(IPhead.protocol == UDP ) /* UDP */
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{
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! memcpy(&UDPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct UDP_header));
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! unwrapped->UDP_len = UDP_HEADLENGTH;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->UDP_len);
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return UDP;
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}
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return -1;
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--- 77,150 ----
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/* restore orig buffer */
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/* general programming rule */
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}
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+
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+ #ifdef DEBUG_ONSCREEN
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+ printf("IPheadlen: %d total length: %d\n", unwrapped->IP_len,
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+ ntohs(IPhead.length));
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+ #endif
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+
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+ dummy=ntohs(IPhead.flag_offset); dummy<<=3;
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+ if( dummy!=0 ) /* we have offset */
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+ {
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+ unwrapped->FRAG_nf = 1;
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+ }
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+
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if(IPhead.protocol == TCP ) /* TCP */
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{
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! if(unwrapped->FRAG_nf == 0)
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! {
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! if( (ntohs(IPhead.length)-(unwrapped->IP_len))<20 )
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! {return CORRUPT_IP;};
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!
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! memcpy(&TCPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct TCP_header));
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! unwrapped->TCP_len = ntohs(TCPhead.offset_flag) & 0xF000;
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! unwrapped->TCP_len >>= 10;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->TCP_len);
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+ }
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+ else
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+ {
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+ unwrapped->DATA_len = ntohs(IPhead.length) - (unwrapped->IP_len);
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+ }
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return TCP;
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}
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if(IPhead.protocol == ICMP ) /* ICMP */
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{
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! if(unwrapped->FRAG_nf == 0)
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! {
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! if( (ntohs(IPhead.length)-(unwrapped->IP_len))<4 )
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! {return CORRUPT_IP;};
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!
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! memcpy(&ICMPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct ICMP_header));
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! unwrapped->ICMP_len = ICMP_HEADLENGTH;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->ICMP_len);
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! return ICMP;
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! }
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! else
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! {
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! return -1; /* don't handle fragmented ICMP */
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! }
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}
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if(IPhead.protocol == UDP ) /* UDP */
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{
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! if(unwrapped->FRAG_nf == 0)
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! {
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! if( (ntohs(IPhead.length)-(unwrapped->IP_len))<8 )
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! {return CORRUPT_IP;};
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!
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! memcpy(&UDPhead,(sp+PROTO_HEAD+(unwrapped->IP_len)),
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sizeof(struct UDP_header));
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! unwrapped->UDP_len = UDP_HEADLENGTH;
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! unwrapped->DATA_len = ntohs(IPhead.length) -
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(unwrapped->IP_len) - (unwrapped->UDP_len);
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+ }
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+ else
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+ {
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+ unwrapped->DATA_len = ntohs(IPhead.length)-(unwrapped->IP_len);
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+ }
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return UDP;
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}
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return -1;
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*** sn_packetstructs.h Fri Apr 18 11:33:58 1997
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--- sn_packetstructs.h Thu Jul 24 16:17:20 1997
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***************
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*** 44,51 ****
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unsigned short length, checksum;
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};
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! struct unwrap /* some extra info */
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{
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int IP_len, TCP_len, ICMP_len, UDP_len; /* header lengths */
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int DATA_len;
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};
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--- 44,52 ----
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unsigned short length, checksum;
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};
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! struct unwrap /* some extra info */
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{
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int IP_len, TCP_len, ICMP_len, UDP_len; /* header lengths */
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int DATA_len;
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+ char FRAG_nf; /* not the first fragment */
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};
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*** sniffit.0.3.5.c Fri Apr 18 11:33:58 1997
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--- sniffit.0.3.5.c Thu Aug 22 19:19:49 1985
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***************
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*** 411,421 ****
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--- 411,427 ----
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proto=unwrap_packet(sp, info);
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if(proto == NO_IP) return DONT_EXAMINE; /* no use in trying */
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if(proto == NO_IP_4) return DONT_EXAMINE; /* no use in trying */
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+ if(proto == CORRUPT_IP)
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+ {printf("Suspicious Packet detected... (Split header)\n");
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+ return DONT_EXAMINE;}
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memcpy(&iphead,(sp+PROTO_HEAD),sizeof(struct IP_header));
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so=(unsigned char *)&(iphead.source);
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dest=(unsigned char *)&(iphead.destination);
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+ if(info->FRAG_nf!=0)
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+ {printf("Fragment Skipped...\n"); return DONT_EXAMINE; };
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+
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if((proto==TCP)&&(PROTOCOLS&F_TCP))
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{
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#ifdef DEBUG_ONSCREEN
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***************
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*** 1220,1225 ****
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--- 1226,1235 ----
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proto=unwrap_packet(sp, info);
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if(proto == NO_IP) return DONT_EXAMINE; /* no use in trying */
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if(proto == NO_IP_4) return DONT_EXAMINE; /* no use in trying */
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+ if(proto == CORRUPT_IP) return DONT_EXAMINE; /* no use in trying */
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+
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+ if(info->FRAG_nf!=0)
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+ {return DONT_EXAMINE; };
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(*IP_nr_of_packets)++;
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if(proto==ICMP)
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