[PATCH v2 12/23] util: Correct sock_l4() binding for link local addresses

When binding an IPv6 socket in sock_l4() we need to supply a scope id if the address is link-local. We check for this by comparing the given address to c->ip6.addr_ll. This is correct only by accident: while c->ip6.addr_ll is typically set to the host interface's link local address, the actual purpose of it is to provide a link local address for passt's private use on the tap interface. Instead set the scope id for any link-local address we're binding to. We're going to need something and this is what makes sense for sockets on the host. It doesn't make sense for PIF_SPLICE sockets, but those should always have loopback, not link-local addresses. Signed-off-by: David Gibson --- util.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/util.c b/util.c index 7cb2c10f..f9f8113c 100644 --- a/util.c +++ b/util.c @@ -199,8 +199,7 @@ int sock_l4(const struct ctx *c, sa_family_t af, enum epoll_type type, if (bind_addr) { addr6.sin6_addr = *(struct in6_addr *)bind_addr; - if (!memcmp(bind_addr, &c->ip6.addr_ll, - sizeof(c->ip6.addr_ll))) + if (IN6_IS_ADDR_LINKLOCAL(bind_addr)) addr6.sin6_scope_id = c->ifi6; } return sock_l4_sa(c, type, &addr6, sizeof(addr6), ifname, -- 2.46.0