From 15033f0457dca569b284bef0c8d3ad55fb37eacb Mon Sep 17 00:00:00 2001 From: Andre Naujoks Date: Mon, 10 Sep 2018 10:27:15 +0200 Subject: [PATCH] ipv6: Add sockopt IPV6_MULTICAST_ALL analogue to IP_MULTICAST_ALL The socket option will be enabled by default to ensure current behaviour is not changed. This is the same for the IPv4 version. A socket bound to in6addr_any and a specific port will receive all traffic on that port. Analogue to IP_MULTICAST_ALL, disable this behaviour, if one or more multicast groups were joined (using said socket) and only pass on multicast traffic from groups, which were explicitly joined via this socket. Without this option disabled a socket (system even) joined to multiple multicast groups is very hard to get right. Filtering by destination address has to take place in user space to avoid receiving multicast traffic from other multicast groups, which might have traffic on the same port. The extension of the IP_MULTICAST_ALL socketoption to just apply to ipv6, too, is not done to avoid changing the behaviour of current applications. Signed-off-by: Andre Naujoks Acked-By: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- include/linux/ipv6.h | 3 ++- include/uapi/linux/in6.h | 1 + net/ipv6/af_inet6.c | 1 + net/ipv6/ipv6_sockglue.c | 11 +++++++++++ net/ipv6/mcast.c | 2 +- 5 files changed, 16 insertions(+), 2 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 8415bf1a9776..495e834c1367 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -274,7 +274,8 @@ struct ipv6_pinfo { */ dontfrag:1, autoflowlabel:1, - autoflowlabel_set:1; + autoflowlabel_set:1, + mc_all:1; __u8 min_hopcount; __u8 tclass; __be32 rcv_flowinfo; diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h index ed291e55f024..71d82fe15b03 100644 --- a/include/uapi/linux/in6.h +++ b/include/uapi/linux/in6.h @@ -177,6 +177,7 @@ struct in6_flowlabel_req { #define IPV6_V6ONLY 26 #define IPV6_JOIN_ANYCAST 27 #define IPV6_LEAVE_ANYCAST 28 +#define IPV6_MULTICAST_ALL 29 /* IPV6_MTU_DISCOVER values */ #define IPV6_PMTUDISC_DONT 0 diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 9a4261e50272..77ef8478234f 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -209,6 +209,7 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol, np->hop_limit = -1; np->mcast_hops = IPV6_DEFAULT_MCASTHOPS; np->mc_loop = 1; + np->mc_all = 1; np->pmtudisc = IPV6_PMTUDISC_WANT; np->repflow = net->ipv6.sysctl.flowlabel_reflect; sk->sk_ipv6only = net->ipv6.sysctl.bindv6only; diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index c0cac9cc3a28..381ce38940ae 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -674,6 +674,13 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, retv = ipv6_sock_ac_drop(sk, mreq.ipv6mr_ifindex, &mreq.ipv6mr_acaddr); break; } + case IPV6_MULTICAST_ALL: + if (optlen < sizeof(int)) + goto e_inval; + np->mc_all = valbool; + retv = 0; + break; + case MCAST_JOIN_GROUP: case MCAST_LEAVE_GROUP: { @@ -1266,6 +1273,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname, val = np->mcast_oif; break; + case IPV6_MULTICAST_ALL: + val = np->mc_all; + break; + case IPV6_UNICAST_IF: val = (__force int)htonl((__u32) np->ucast_oif); break; diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 4ae54aaca373..6895e1dc0b03 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -636,7 +636,7 @@ bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr, } if (!mc) { rcu_read_unlock(); - return true; + return np->mc_all; } read_lock(&mc->sflock); psl = mc->sflist;