Re: [B.A.T.M.A.N.] [RFCv2] batctl tcpdump: add IPv6 support to tcpdump parser

On Tue, Sep 17, 2013 at 02:08:14PM +0200, Marco Dalla Torre wrote:

• switch (iphdr->ip6_nxt) {
• case IPPROTO_ICMPV6:

• LEN_CHECK(
  

• 	(size_t)buff_len - (size_t)(sizeof(struct ip6_hdr)),
  

• 	sizeof(struct icmp6_hdr),
  

• 	"ICMPv6");
  

• icmphdr = (struct icmp6_hdr *)(packet_buff +
  

• 			       sizeof(struct ip6_hdr));
  

• inet_ntop(AF_INET6, &(iphdr->ip6_src), nd_ipv6_addr, 40);
  

• printf("IPv6 %s > ", nd_ipv6_addr);
  

• switch (icmphdr->icmp6_type) {
  

• case ICMP6_DST_UNREACH:
  

• 	if ((size_t)(buff_len) < IPV6_MIN_MTU) {
  

• 		fprintf(stderr,
  

• 			"Warning - dropping received 'ICMPv6 destination unreached' packet as it is bigger than maximum allowed size (%u): %zu\n",
  

• 			IPV6_MIN_MTU, (size_t)(buff_len));
  

Is the message wrong? should it be the other way around? "packet is smaller than minimum size" ? And why should _only_ this ICMP packet be bigger of IPV6_MIN_MTU ?

Cheers,