Repository : ssh://git@open-mesh.org/batctl
On branch : maint
commit b6adee861f9741f214b3bd7e506c30ba1da7cb2b 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
b6adee861f9741f214b3bd7e506c30ba1da7cb2b tcpdump.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tcpdump.c b/tcpdump.c index b4cfec9..f5bb574 100644 --- a/tcpdump.c +++ b/tcpdump.c @@ -196,6 +196,7 @@ 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"); @@ -259,16 +260,18 @@ 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");