On Tuesday 2008-01-08 06:58, Ashwini R wrote: > >struct ip_options *opt = kzalloc(sizeof(struct ip_options) + ((srlen + >3) & ~3), GFP_KERNEL); >memcpy(opt->__data, srp, srlen); > >But, I am not sure how to add this new ip_options to the captured >packet since I need to append the ip_options structure to the ip >header of the packet. You basically have to rebuild the IP packet. How exactly you do it (#1 or #2) is up to you. #1. Create new packet of appropraite size, copy IP header, put options in place, copy payload. #2. Cloning packet, expanding packet size, moving payload forwards, adding IP options in the appropriate place. >Also, I am not sure how to specify the new packet length, if I need to >recompute the checksum, etc. I think skb_realloc_headroom is needed here... /* GFP_KERNEL only allowed on LOCAL_OUT and POST_ROUTING */ nskb = skb_realloc_headroom(skb, size_of_your_option_data, 0, GFP_KERNEL); void *oiph = ip_hdr(skb); void *niph = skb_push(skb, size_of_your_option_data); memmove(niph, oiph, sizeof(struct iphdr) + size_of_existing_options); then fill in the space that just got vacant with your new options. Afterwards recalculate checksum. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
