From 6c26a77124ff94102ea59ac23a54cdad2c49e644 Mon Sep 17 00:00:00 2001 From: Spencer Baugh Date: Thu, 13 Aug 2015 12:19:10 -0700 Subject: [PATCH] RDMA/cma: fix IPv6 address resolution Resolving a link-local IPv6 address with an unspecified source address was broken by commit 5462eddd7a, which prevented the IPv6 stack from learning the scope id of the link-local IPv6 address, causing random failures as the IP stack chose a random link to resolve the address on. This commit 5462eddd7a made us bail out of cma_check_linklocal early if the address passed in was not an IPv6 link-local address. On the address resolution path, the address passed in is the source address; if the source address is the unspecified address, which is not link-local, we will bail out early. This is mostly correct, but if the destination address is a link-local address, then we will be following a link-local route, and we'll need to tell the IPv6 stack what the scope id of the destination address is. This used to be done by last line of cma_check_linklocal, which is skipped when bailing out early: dev_addr->bound_dev_if = sin6->sin6_scope_id; (In cma_bind_addr, the sin6_scope_id of the source address is set to the sin6_scope_id of the destination address, so this is correct) This line is required in turn for the following line, L279 of addr6_resolve, to actually inform the IPv6 stack of the scope id: fl6.flowi6_oif = addr->bound_dev_if; Since we can only know we are in this failure case when we have access to both the source IPv6 address and destination IPv6 address, we have to deal with this further up the stack. So detect this failure case in cma_bind_addr, and set bound_dev_if to the destination address scope id to correct it. Signed-off-by: Spencer Baugh Signed-off-by: Doug Ledford --- drivers/infiniband/core/cma.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 143ded2bbe7c..4e72e4c16cfe 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -2203,8 +2203,11 @@ static int cma_bind_addr(struct rdma_cm_id *id, struct sockaddr *src_addr, src_addr = (struct sockaddr *) &id->route.addr.src_addr; src_addr->sa_family = dst_addr->sa_family; if (dst_addr->sa_family == AF_INET6) { - ((struct sockaddr_in6 *) src_addr)->sin6_scope_id = - ((struct sockaddr_in6 *) dst_addr)->sin6_scope_id; + struct sockaddr_in6 *src_addr6 = (struct sockaddr_in6 *) src_addr; + struct sockaddr_in6 *dst_addr6 = (struct sockaddr_in6 *) dst_addr; + src_addr6->sin6_scope_id = dst_addr6->sin6_scope_id; + if (ipv6_addr_type(&dst_addr6->sin6_addr) & IPV6_ADDR_LINKLOCAL) + id->route.addr.dev_addr.bound_dev_if = dst_addr6->sin6_scope_id; } else if (dst_addr->sa_family == AF_IB) { ((struct sockaddr_ib *) src_addr)->sib_pkey = ((struct sockaddr_ib *) dst_addr)->sib_pkey; -- 2.34.1