From 36cbb2452cbafca64dcdd3578047433787900cf0 Mon Sep 17 00:00:00 2001 From: Rick Jones Date: Thu, 6 Nov 2014 10:37:54 -0800 Subject: [PATCH] udp: Increment UDP_MIB_IGNOREDMULTI for arriving unmatched multicasts As NIC multicast filtering isn't perfect, and some platforms are quite content to spew broadcasts, we should not trigger an event for skb:kfree_skb when we do not have a match for such an incoming datagram. We do though want to avoid sweeping the matter under the rug entirely, so increment a suitable statistic. This incorporates feedback from David L. Stevens, Karl Neiss and Eric Dumazet. V3 - use bool per David Miller Signed-off-by: Rick Jones Signed-off-by: David S. Miller --- include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/udp.c | 12 +++++++++--- net/ipv6/proc.c | 1 + net/ipv6/udp.c | 11 ++++++++--- 5 files changed, 20 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index df40137f33dd..30f541b32895 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -156,6 +156,7 @@ enum UDP_MIB_RCVBUFERRORS, /* RcvbufErrors */ UDP_MIB_SNDBUFERRORS, /* SndbufErrors */ UDP_MIB_CSUMERRORS, /* InCsumErrors */ + UDP_MIB_IGNOREDMULTI, /* IgnoredMulti */ __UDP_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index f0d4eb8b99b9..6513ade8d6dc 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -181,6 +181,7 @@ static const struct snmp_mib snmp4_udp_list[] = { SNMP_MIB_ITEM("RcvbufErrors", UDP_MIB_RCVBUFERRORS), SNMP_MIB_ITEM("SndbufErrors", UDP_MIB_SNDBUFERRORS), SNMP_MIB_ITEM("InCsumErrors", UDP_MIB_CSUMERRORS), + SNMP_MIB_ITEM("IgnoredMulti", UDP_MIB_IGNOREDMULTI), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index df19027f44f3..5d0fdca8e965 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1647,7 +1647,8 @@ static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, struct udphdr *uh, __be32 saddr, __be32 daddr, - struct udp_table *udptable) + struct udp_table *udptable, + int proto) { struct sock *sk, *stack[256 / sizeof(struct sock *)]; struct hlist_nulls_node *node; @@ -1656,6 +1657,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, int dif = skb->dev->ifindex; unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node); unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10); + bool inner_flushed = false; if (use_hash2) { hash2_any = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum) & @@ -1674,6 +1676,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, dif, hnum)) { if (unlikely(count == ARRAY_SIZE(stack))) { flush_stack(stack, count, skb, ~0); + inner_flushed = true; count = 0; } stack[count++] = sk; @@ -1695,7 +1698,10 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb, if (count) { flush_stack(stack, count, skb, count - 1); } else { - kfree_skb(skb); + if (!inner_flushed) + UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI, + proto == IPPROTO_UDPLITE); + consume_skb(skb); } return 0; } @@ -1781,7 +1787,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST)) return __udp4_lib_mcast_deliver(net, skb, uh, - saddr, daddr, udptable); + saddr, daddr, udptable, proto); sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable); if (sk != NULL) { diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c index 1752cd0b4882..679253d0af84 100644 --- a/net/ipv6/proc.c +++ b/net/ipv6/proc.c @@ -136,6 +136,7 @@ static const struct snmp_mib snmp6_udp6_list[] = { SNMP_MIB_ITEM("Udp6RcvbufErrors", UDP_MIB_RCVBUFERRORS), SNMP_MIB_ITEM("Udp6SndbufErrors", UDP_MIB_SNDBUFERRORS), SNMP_MIB_ITEM("Udp6InCsumErrors", UDP_MIB_CSUMERRORS), + SNMP_MIB_ITEM("Udp6IgnoredMulti", UDP_MIB_IGNOREDMULTI), SNMP_MIB_SENTINEL }; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 9b6809232b17..b756355e9739 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -771,7 +771,7 @@ static void udp6_csum_zero_error(struct sk_buff *skb) */ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, const struct in6_addr *saddr, const struct in6_addr *daddr, - struct udp_table *udptable) + struct udp_table *udptable, int proto) { struct sock *sk, *stack[256 / sizeof(struct sock *)]; const struct udphdr *uh = udp_hdr(skb); @@ -781,6 +781,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, int dif = inet6_iif(skb); unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node); unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10); + bool inner_flushed = false; if (use_hash2) { hash2_any = udp6_portaddr_hash(net, &in6addr_any, hnum) & @@ -803,6 +804,7 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, (uh->check || udp_sk(sk)->no_check6_rx)) { if (unlikely(count == ARRAY_SIZE(stack))) { flush_stack(stack, count, skb, ~0); + inner_flushed = true; count = 0; } stack[count++] = sk; @@ -821,7 +823,10 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, if (count) { flush_stack(stack, count, skb, count - 1); } else { - kfree_skb(skb); + if (!inner_flushed) + UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI, + proto == IPPROTO_UDPLITE); + consume_skb(skb); } return 0; } @@ -873,7 +878,7 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, */ if (ipv6_addr_is_multicast(daddr)) return __udp6_lib_mcast_deliver(net, skb, - saddr, daddr, udptable); + saddr, daddr, udptable, proto); /* Unicast */ -- GitLab