From 7a6078f0122271f97944ed9a9db4d134badff676 Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Fri, 5 Feb 2016 08:33:32 -0200 Subject: [PATCH] packets: fix compose_nd to not crash system packet_set_ipv6 and packet_set_nd assumed that valid packets were already in place, so they were not a good fit for composing new packets. In fact, packet_set_ipv6 didn't even set the IP version or set L4 offset, causing crashes when compose_nd tried to access L4. This patch introduces ipv6_compose and uses it for compose_nd, then set the ND packets without other helpers. Signed-off-by: Thadeu Lima de Souza Cascardo --- lib/packets.c | 46 ++++++++++++++++++++++++++++++++++++++-------- lib/packets.h | 3 +++ 2 files changed, 41 insertions(+), 8 deletions(-) diff --git a/lib/packets.c b/lib/packets.c index b5d141a35..17d468af0 100644 --- a/lib/packets.c +++ b/lib/packets.c @@ -1288,6 +1288,24 @@ compose_arp(struct dp_packet *b, uint16_t arp_op, dp_packet_set_l3(b, arp); } +void +ipv6_compose(struct dp_packet *packet, uint8_t proto, + const struct in6_addr *src, const struct in6_addr *dst, + uint8_t key_tc, ovs_be32 key_fl, uint8_t key_hl) +{ + struct ovs_16aligned_ip6_hdr *ip6 = dp_packet_l3(packet); + ovs_be32 old_flow; + ip6->ip6_vfc = 0x60; + ip6->ip6_nxt = proto; + ip6->ip6_hlim = key_hl; + ip6->ip6_plen = 0; + old_flow = get_16aligned_be32(&ip6->ip6_flow) & htonl(0xF00FFFFF | ~IPV6_LABEL_MASK); + put_16aligned_be32(&ip6->ip6_flow, old_flow | key_fl | htonl(key_tc << 20)); + memcpy(&ip6->ip6_src, src, sizeof(ovs_be32[4])); + memcpy(&ip6->ip6_dst, dst, sizeof(ovs_be32[4])); + dp_packet_set_l4(packet, ip6 + 1); +} + void compose_nd(struct dp_packet *b, const struct eth_addr eth_src, struct in6_addr * ipv6_src, struct in6_addr * ipv6_dst) @@ -1296,26 +1314,38 @@ compose_nd(struct dp_packet *b, const struct eth_addr eth_src, struct eth_addr eth_dst; struct ovs_nd_msg *ns; struct ovs_nd_opt *nd_opt; + struct ovs_16aligned_ip6_hdr *ip6; + size_t plen = ND_MSG_LEN + ND_OPT_LEN; + uint32_t csum; in6_addr_solicited_node(&sn_addr, ipv6_dst); ipv6_multicast_to_ethernet(ð_dst, &sn_addr); - eth_compose(b, eth_dst, eth_src, ETH_TYPE_IPV6, - IPV6_HEADER_LEN + ICMP6_HEADER_LEN + ND_OPT_LEN); - packet_set_ipv6(b, IPPROTO_ICMPV6, - ALIGNED_CAST(ovs_be32 *, ipv6_src->s6_addr), - ALIGNED_CAST(ovs_be32 *, sn_addr.s6_addr), - 0, 0, 255); + eth_compose(b, eth_dst, eth_src, ETH_TYPE_IPV6, IPV6_HEADER_LEN + plen); + ipv6_compose(b, IPPROTO_ICMPV6, ipv6_src, &sn_addr, 0, 0, 255); + ip6 = dp_packet_l3(b); + ip6->ip6_plen = htons(plen); ns = dp_packet_l4(b); + memset(ns, 0, plen); nd_opt = &ns->options[0]; ns->icmph.icmp6_type = ND_NEIGHBOR_SOLICIT; ns->icmph.icmp6_code = 0; + memcpy(ns->target.be32, ipv6_dst, sizeof(ovs_be32[4])); nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR; - packet_set_nd(b, ALIGNED_CAST(ovs_be32 *, ipv6_dst->s6_addr), - eth_src, eth_addr_zero); + nd_opt->nd_opt_len = 1; + nd_opt->nd_opt_mac = eth_src; + + ns->icmph.icmp6_cksum = 0; + csum = packet_csum_pseudoheader6(ip6, htonl(plen)); + csum = csum_continue(csum, &ns->icmph, plen); + csum = csum_finish(csum); + ns->icmph.icmp6_cksum = csum; + if (!ns->icmph.icmp6_cksum) { + ns->icmph.icmp6_cksum = htons(0xffff); + } } uint32_t diff --git a/lib/packets.h b/lib/packets.h index d2a9b51ee..23992b4e2 100644 --- a/lib/packets.h +++ b/lib/packets.h @@ -1072,6 +1072,9 @@ void packet_set_nd(struct dp_packet *, const ovs_be32 target[4], void packet_format_tcp_flags(struct ds *, uint16_t); const char *packet_tcp_flag_to_string(uint32_t flag); +void ipv6_compose(struct dp_packet *, uint8_t proto, const struct in6_addr *src, + const struct in6_addr *dst, uint8_t tc, + ovs_be32 fl, uint8_t hlmit); void compose_arp(struct dp_packet *, uint16_t arp_op, const struct eth_addr arp_sha, const struct eth_addr arp_tha, bool broadcast, -- 2.20.1