| 1 | #include <stdio.h> |
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| 2 | #include "libpacketdump.h" |
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| 3 | |
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| 4 | #define LE(lhs,n) \ |
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| 5 | do { \ |
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| 6 | uint64_t num=0; \ |
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| 7 | int size=0; \ |
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| 8 | if ((offset+n)>len*8) return; \ |
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| 9 | if (n>16) { \ |
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| 10 | num=htonl(*(uint32_t*)(packet+offset/8));\ |
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| 11 | size = 32;\ |
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| 12 | } else if (n>8) { \ |
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| 13 | num=htons(*(uint16_t*)(packet+offset/8));\ |
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| 14 | size = 16; \ |
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| 15 | } else { \ |
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| 16 | num=*(uint8_t*)(packet+offset/8); \ |
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| 17 | size = 8; \ |
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| 18 | } \ |
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| 19 | num=num>>(size - (n + (offset % 8))); \ |
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| 20 | offset+=n; \ |
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| 21 | lhs=num&((1<<(n))-1); \ |
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| 22 | } while(0) |
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| 23 | |
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| 24 | DLLEXPORT void decode(int link_type UNUSED,const char *packet,unsigned len) |
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| 25 | { |
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| 26 | unsigned int offset=0; |
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| 27 | int value; |
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| 28 | int more = 0; |
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| 29 | LE(value,20); printf(" MPLS: Label: %d\n",value); |
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| 30 | LE(value,3); printf(" MPLS: Class of service: %d\n",value); |
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| 31 | LE(value,1); printf(" MPLS: Stack: %s\n",value?"Last" :"More"); |
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| 32 | if (value == 0) more = 1; |
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| 33 | LE(value,8); printf(" MPLS: TTL: %d\n",value); |
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| 34 | |
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| 35 | /* MPLS doesn't say what it's encapsulating, so we make an educated |
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| 36 | * guess and pray. |
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| 37 | */ |
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| 38 | if (more) |
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| 39 | decode_next(packet+offset/8,len-4,"eth",0x8847); |
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| 40 | else if ((*(packet+4)&0xF0) == 0x40) |
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| 41 | decode_next(packet+offset/8,len-4,"eth",0x0800); |
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| 42 | else if ((*(packet+4)&0xF0) == 0x60) |
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| 43 | decode_next(packet+offset/8,len-4,"eth",0x86DD); |
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| 44 | else |
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| 45 | decode_next(packet+offset/8,len-4,"link",1); |
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| 46 | |
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| 47 | return; |
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| 48 | } |
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