From 15606f264c84f9cc01d2f60adb6eda6584ef2594 Mon Sep 17 00:00:00 2001 From: "Joseph C. Sible" Date: Sun, 2 Sep 2018 14:09:15 -0400 Subject: doc: Improve layout of u32 instructions Make it more clear where the instruction ends, and where what it does begins. Signed-off-by: Joseph C. Sible Signed-off-by: Florian Westphal --- extensions/libxt_u32.man | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) (limited to 'extensions') diff --git a/extensions/libxt_u32.man b/extensions/libxt_u32.man index 7c8615d3..40a69f8e 100644 --- a/extensions/libxt_u32.man +++ b/extensions/libxt_u32.man @@ -40,18 +40,23 @@ A is of type \fBchar *\fP, initially the address of the IP header B and C are unsigned 32 bit integers, initially zero .PP The instructions are: -.IP -number B = number; +.TP +.B number +B = number; .IP C = (*(A+B)<<24) + (*(A+B+1)<<16) + (*(A+B+2)<<8) + *(A+B+3) -.IP -&number C = C & number -.IP -<< number C = C << number -.IP ->> number C = C >> number -.IP -@number A = A + C; then do the instruction number +.TP +.B &number +C = C & number +.TP +.B << number +C = C << number +.TP +.B >> number +C = C >> number +.TP +.B @number +A = A + C; then do the instruction number .PP 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. -- cgit v1.2.3