Repository : ssh://git@open-mesh.org/batctl
On branch : next
commit e374a3fe9b40903591ba8049195fb9327a086ea9 Author: Marco Dalla Torre marco.dallato@gmail.com Date: Sat Sep 21 17:05:07 2013 +0200
batctl tcpdump: Fix reported length of TCP payload
Fixes the erratic report of TCP payload length in 'batctl tcpdump'. Previously TCP header length size was considered fixed, while this is actually not the case given the variable length (or no presence at all) of the options field.
Signed-off-by: Marco Dalla Torre marco.dallato@gmail.com Signed-off-by: Marek Lindner mareklindner@neomailbox.ch
e374a3fe9b40903591ba8049195fb9327a086ea9 tcpdump.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tcpdump.c b/tcpdump.c index a220c3c..8f39ac0 100644 --- a/tcpdump.c +++ b/tcpdump.c @@ -198,6 +198,7 @@ static void dump_ip(unsigned char *packet_buff, ssize_t buff_len, int time_print struct tcphdr *tcphdr; struct udphdr *udphdr, *tmp_udphdr; struct icmphdr *icmphdr; + uint16_t tcp_header_len;
iphdr = (struct iphdr *)packet_buff; LEN_CHECK((size_t)buff_len, (size_t)(iphdr->ihl * 4), "IP"); @@ -261,16 +262,18 @@ static void dump_ip(unsigned char *packet_buff, ssize_t buff_len, int time_print
break; case IPPROTO_TCP: - LEN_CHECK((size_t)buff_len - (iphdr->ihl * 4), sizeof(struct tcphdr), "TCP"); - tcphdr = (struct tcphdr *)(packet_buff + (iphdr->ihl * 4)); + tcp_header_len = tcphdr->doff * 4; + LEN_CHECK((size_t)buff_len - (iphdr->ihl * 4), + (size_t)tcp_header_len, "TCP"); + printf("IP %s.%i > ", inet_ntoa(*(struct in_addr *)&iphdr->saddr), ntohs(tcphdr->source)); printf("%s.%i: TCP, flags [%c%c%c%c%c%c], length %zu\n", inet_ntoa(*(struct in_addr *)&iphdr->daddr), ntohs(tcphdr->dest), (tcphdr->fin ? 'F' : '.'), (tcphdr->syn ? 'S' : '.'), (tcphdr->rst ? 'R' : '.'), (tcphdr->psh ? 'P' : '.'), (tcphdr->ack ? 'A' : '.'), (tcphdr->urg ? 'U' : '.'), - (size_t)buff_len - (iphdr->ihl * 4) - sizeof(struct tcphdr)); + (size_t)buff_len - (iphdr->ihl * 4) - tcp_header_len); break; case IPPROTO_UDP: LEN_CHECK((size_t)buff_len - (iphdr->ihl * 4), sizeof(struct udphdr), "UDP");