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| author | Guy Harris <guy@alum.mit.edu> | 2011-11-30 19:02:30 -0800 |
|---|---|---|
| committer | Guy Harris <guy@alum.mit.edu> | 2011-11-30 19:02:57 -0800 |
| commit | 0471082f20bcc02196bd85f665f7f34c71ba8845 (patch) | |
| tree | 92a925f5a65d98467e3aa6d2b1617673f1a18f44 | |
| parent | 59a971d93df078875f26430e9bddc4165b23697f (diff) | |
| download | libpcap-0471082f20bcc02196bd85f665f7f34c71ba8845.tar.gz | |
Fix the code generated for "ip protochain".
| -rw-r--r-- | gencode.c | 25 |
1 files changed, 8 insertions, 17 deletions
@@ -5814,12 +5814,9 @@ gen_protochain(v, proto, dir) /* * in short, - * A = P[X]; - * X = X + (P[X + 1] + 1) * 8; + * A = P[X + packet head]; + * X = X + (P[X + packet head + 1] + 1) * 8; */ - /* A = X */ - s[i] = new_stmt(BPF_MISC|BPF_TXA); - i++; /* A = P[X + packet head] */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); s[i]->s.k = off_macpl + off_nl; @@ -5828,19 +5825,9 @@ gen_protochain(v, proto, dir) s[i] = new_stmt(BPF_ST); s[i]->s.k = reg2; i++; - /* A = X */ - s[i] = new_stmt(BPF_MISC|BPF_TXA); - i++; - /* A += 1 */ - s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); - s[i]->s.k = 1; - i++; - /* X = A */ - s[i] = new_stmt(BPF_MISC|BPF_TAX); - i++; - /* A = P[X + packet head]; */ + /* A = P[X + packet head + 1]; */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); - s[i]->s.k = off_macpl + off_nl; + s[i]->s.k = off_macpl + off_nl + 1; i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); @@ -5850,6 +5837,10 @@ gen_protochain(v, proto, dir) s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K); s[i]->s.k = 8; i++; + /* A += X */ + s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_X); + s[i]->s.k = 0; + i++; /* X = A; */ s[i] = new_stmt(BPF_MISC|BPF_TAX); i++; |