How to get TCP options

[neo-hu]

How to get client IP (toa) in TCP option

[chenhengqi]

This is not related to BCC itself. Please check the following code on how to parse TCP header:

bcc/examples/networking/tcp_mon_block/src/tcp_mon_block.c

Lines 120 to 133 in 10ee9d9

	tcp = (void *)ip + sizeof(*ip);
	if (tcp_header_bound_check(tcp, data_end))
	{
	return TC_ACT_OK;
	}
	u8 tcpflags = ((u_int8_t *)tcp)[13];
	u16 src_port = bpf_ntohs(tcp->source);
	u16 dst_port = bpf_ntohs(tcp->dest);
	key.src_ip = ip->saddr;
	key.src_port = src_port;
	key.dst_ip = ip->daddr;
	key.dst_port = dst_port;