When using HEAD from https://git.kernel.org/cgit/utils/kernel/ipvsadm/ipvsadm.git/, the command: ipvsadm --start-daemon backup --mcast-interface eth0.60 --mcast-group ff01::1:81 fails with the error message: Argument list too long
whereas both: ipvsadm --start-daemon master --mcast-interface eth0.60 --mcast-group ff01::1:81 and: ipvsadm --start-daemon backup --mcast-interface eth0.60 --mcast-group 224.0.0.81 are successful. The error message "Argument list too long" isn't helpful. The error occurs because an IPv6 address is given in backup mode. The error is in make_receive_sock() in net/netfilter/ipvs/ip_vs_sync.c, since it fails to set the interface on the address or the socket before calling inet6_bind() (via sock->ops->bind), where the test 'if (!sk->sk_bound_dev_if)' failed. Setting sin6_scope_id on the sockaddr before calling inet6_bind() resolves the issue. Signed-off-by: Quentin Armitage <quen...@armitage.org.uk> --- net/netfilter/ipvs/ip_vs_sync.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c index 803001a..85b48f1 100644 --- a/net/netfilter/ipvs/ip_vs_sync.c +++ b/net/netfilter/ipvs/ip_vs_sync.c @@ -1545,7 +1545,7 @@ error: /* * Set up receiving multicast socket over UDP */ -static struct socket *make_receive_sock(struct netns_ipvs *ipvs, int id) +static struct socket *make_receive_sock(struct netns_ipvs *ipvs, int id, int ifindex) { /* multicast addr */ union ipvs_sockaddr mcast_addr; @@ -1566,6 +1566,7 @@ static struct socket *make_receive_sock(struct netns_ipvs *ipvs, int id) set_sock_size(sock->sk, 0, result); get_mcast_sockaddr(&mcast_addr, &salen, &ipvs->bcfg, id); + ((struct sockaddr_in6 *)&mcast_addr)->sin6_scope_id = ifindex; result = sock->ops->bind(sock, (struct sockaddr *)&mcast_addr, salen); if (result < 0) { pr_err("Error binding to the multicast addr\n"); @@ -1868,7 +1869,7 @@ int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c, if (state == IP_VS_STATE_MASTER) sock = make_send_sock(ipvs, id); else - sock = make_receive_sock(ipvs, id); + sock = make_receive_sock(ipvs, id, dev->ifindex); if (IS_ERR(sock)) { result = PTR_ERR(sock); goto outtinfo; -- 1.7.7.6