From c9b64d492b1fbc732e3a26b284060c949b737bce Mon Sep 17 00:00:00 2001 From: Richard Alpe Date: Fri, 26 Aug 2016 10:52:54 +0200 Subject: [PATCH] tipc: add replicast peer discovery Automatically learn UDP remote IP addresses of communicating peers by looking at the source IP address of incoming TIPC link configuration messages (neighbor discovery). This makes configuration slightly easier and removes the problematic scenario where a node receives directly addressed neighbor discovery messages sent using replicast which the node cannot "reply" to using mutlicast, leaving the link FSM in a limbo state. Signed-off-by: Richard Alpe Reviewed-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/udp_media.c | 83 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 80 insertions(+), 3 deletions(-) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index 6b938cc15daf..6ece3c9ccf82 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -254,6 +254,26 @@ out: return err; } +static bool tipc_udp_is_known_peer(struct tipc_bearer *b, + struct udp_media_addr *addr) +{ + struct udp_replicast *rcast, *tmp; + struct udp_bearer *ub; + + ub = rcu_dereference_rtnl(b->media_ptr); + if (!ub) { + pr_err_ratelimited("UDP bearer instance not found\n"); + return false; + } + + list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) { + if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr))) + return true; + } + + return false; +} + static int tipc_udp_rcast_add(struct tipc_bearer *b, struct udp_media_addr *addr) { @@ -281,29 +301,83 @@ static int tipc_udp_rcast_add(struct tipc_bearer *b, return 0; } +static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb) +{ + struct udp_media_addr src = {0}; + struct udp_media_addr *dst; + + dst = (struct udp_media_addr *)&b->bcast_addr.value; + if (tipc_udp_is_mcast_addr(dst)) + return 0; + + src.port = udp_hdr(skb)->source; + + if (ip_hdr(skb)->version == 4) { + struct iphdr *iphdr = ip_hdr(skb); + + src.proto = htons(ETH_P_IP); + src.ipv4.s_addr = iphdr->saddr; + if (ipv4_is_multicast(iphdr->daddr)) + return 0; +#if IS_ENABLED(CONFIG_IPV6) + } else if (ip_hdr(skb)->version == 6) { + struct ipv6hdr *iphdr = ipv6_hdr(skb); + + src.proto = htons(ETH_P_IPV6); + src.ipv6 = iphdr->saddr; + if (ipv6_addr_is_multicast(&iphdr->daddr)) + return 0; +#endif + } else { + return 0; + } + + if (likely(tipc_udp_is_known_peer(b, &src))) + return 0; + + return tipc_udp_rcast_add(b, &src); +} + /* tipc_udp_recv - read data from bearer socket */ static int tipc_udp_recv(struct sock *sk, struct sk_buff *skb) { struct udp_bearer *ub; struct tipc_bearer *b; + struct tipc_msg *hdr; + int err; ub = rcu_dereference_sk_user_data(sk); if (!ub) { pr_err_ratelimited("Failed to get UDP bearer reference"); - kfree_skb(skb); - return 0; + goto out; } - skb_pull(skb, sizeof(struct udphdr)); + hdr = buf_msg(skb); + rcu_read_lock(); b = rcu_dereference_rtnl(ub->bearer); + if (!b) + goto rcu_out; if (b && test_bit(0, &b->up)) { tipc_rcv(sock_net(sk), skb, b); rcu_read_unlock(); return 0; } + + if (unlikely(msg_user(hdr) == LINK_CONFIG)) { + err = tipc_udp_rcast_disc(b, skb); + if (err) + goto rcu_out; + } + + tipc_rcv(sock_net(sk), skb, b); rcu_read_unlock(); + return 0; + +rcu_out: + rcu_read_unlock(); +out: kfree_skb(skb); return 0; } @@ -398,6 +472,9 @@ int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr) return -EINVAL; } + if (tipc_udp_is_known_peer(b, &addr)) + return 0; + return tipc_udp_rcast_add(b, &addr); } -- 2.30.2