diff options
Diffstat (limited to 'extensions/libxt_u32.man')
| -rw-r--r-- | extensions/libxt_u32.man | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/extensions/libxt_u32.man b/extensions/libxt_u32.man index 8e00cc13..2ffab305 100644 --- a/extensions/libxt_u32.man +++ b/extensions/libxt_u32.man @@ -2,7 +2,7 @@ U32 tests whether quantities of up to 4 bytes extracted from a packet have specified values. The specification of what to extract is general enough to find data at given offsets from tcp headers or payloads. .TP -[\fB!\fP] \fB--u32\fP \fItests\fP +[\fB!\fP] \fB\-\-u32\fP \fItests\fP The argument amounts to a program in a small language described below. .IP tests := location "=" value | tests "&&" location "=" value @@ -53,7 +53,7 @@ C = (*(A+B)<<24) + (*(A+B+1)<<16) + (*(A+B+2)<<8) + *(A+B+3) .IP @number A = A + C; then do the instruction number .PP -Any access of memory outside [skb->data,skb->end] causes the match to fail. +Any access of memory outside [skb\->data,skb\->end] causes the match to fail. Otherwise the result of the computation is the final value of C. .PP Whitespace is allowed but not required in the tests. However, the characters @@ -66,7 +66,7 @@ match IP packets with total length >= 256 .IP The IP header contains a total length field in bytes 2-3. .IP ---u32 "\fB0 & 0xFFFF = 0x100:0xFFFF\fR" +\-\-u32 "\fB0 & 0xFFFF = 0x100:0xFFFF\fP" .IP read bytes 0-3 .IP @@ -79,7 +79,7 @@ match ICMP packets with icmp type 0 .IP First test that it is an ICMP packet, true iff byte 9 (protocol) = 1 .IP ---u32 "\fB6 & 0xFF = 1 &&\fR ... +\-\-u32 "\fB6 & 0xFF = 1 &&\fP ... .IP read bytes 6-9, use \fB&\fR to throw away bytes 6-8 and compare the result to 1. Next test that it is not a fragment. (If so, it might be part of such a @@ -114,7 +114,7 @@ TCP payload bytes 8-12 is any of 1, 2, 5 or 8 .IP First we test that the packet is a tcp packet (similar to ICMP). .IP ---u32 "\fB6 & 0xFF = 6 &&\fR ... +\-\-u32 "\fB6 & 0xFF = 6 &&\fP ... .IP Next, test that it is not a fragment (same as above). .IP |