| 24,7 → 24,7 |
|---|
| ; [esp+4] = buffer size |
| ; ebx = ptr to device struct |
| ; ecx = segment size |
| ; edx = ptr to TCP segment |
| ; esi = ptr to TCP segment |
| ; edi = ptr to ipv4 source address, followed by ipv4 dest address |
| ; |
| ; OUT: / |
| 36,18 → 36,17 |
|---|
| |
| DEBUGF 1,"TCP_input size=%u\n", ecx |
| |
| and [edx + TCP_header.DataOffset], 0xf0 ; Calculate TCP segment header size (throwing away unused reserved bits in TCP header) |
| shr [edx + TCP_header.DataOffset], 2 |
| cmp [edx + TCP_header.DataOffset], sizeof.TCP_header ; Now see if it's at least the size of a standard TCP header |
| and [esi + TCP_header.DataOffset], 0xf0 ; Calculate TCP segment header size (throwing away unused reserved bits in TCP header) |
| shr [esi + TCP_header.DataOffset], 2 |
| cmp [esi + TCP_header.DataOffset], sizeof.TCP_header ; Now see if it's at least the size of a standard TCP header |
| jb .drop_not_locked ; If not, drop the packet |
| |
| ;------------------------------- |
| ; Now, re-calculate the checksum |
| |
| push ecx edx |
| pushw [edx + TCP_header.Checksum] |
| mov [edx + TCP_header.Checksum], 0 |
| mov esi, edx |
| push ecx esi |
| pushw [esi + TCP_header.Checksum] |
| mov [esi + TCP_header.Checksum], 0 |
| TCP_checksum (edi), (edi+4) |
| pop cx ; previous checksum |
| cmp cx, dx |
| 56,7 → 55,8 |
|---|
| |
| DEBUGF 1,"Checksum ok\n" |
| |
| sub ecx, [edx + TCP_header.DataOffset] ; substract TCP header size from total segment size |
| movzx eax, [edx + TCP_header.DataOffset] |
| sub ecx, eax ; substract TCP header size from total segment size |
| jb .drop_not_locked ; If total segment size is less then the advertised header size, drop packet |
| DEBUGF 1,"we got %u bytes of data\n", ecx |
| |
| 63,7 → 63,7 |
|---|
| ;----------------------------------------------------------------------------------------- |
| ; Check if this packet has a timestamp option (We do it here so we can process it quickly) |
| |
| cmp [edx + TCP_header.DataOffset], sizeof.TCP_header + 12 ; Timestamp option is 12 bytes |
| cmp eax, sizeof.TCP_header + 12 ; Timestamp option is 12 bytes |
| jb .no_timestamp |
| je .is_ok |
| |
| 202,8 → 202,8 |
|---|
| ;-------------------- |
| ; Process TCP options |
| |
| mov eax, [edx + TCP_header.DataOffset] |
| cmp eax, TCP_header.DataOffset ; Does header contain any options? |
| movzx eax, [edx + TCP_header.DataOffset] |
| cmp eax, sizeof.TCP_header ; Does header contain any options? |
| je .no_options |
| |
| DEBUGF 1,"Segment has options\n" |