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Commit 36cbb245 authored by Rick Jones's avatar Rick Jones Committed by David S. Miller
Browse files

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: default avatarRick Jones <rick.jones2@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f46ad73a

include/uapi/linux/snmp.h

+1 −0
Original line number Diff line number Diff line
@@ -156,6 +156,7 @@ enum 
	UDP_MIB_RCVBUFERRORS,			/* RcvbufErrors */

	UDP_MIB_SNDBUFERRORS,			/* SndbufErrors */

	UDP_MIB_CSUMERRORS,			/* InCsumErrors */

	UDP_MIB_IGNOREDMULTI,			/* IgnoredMulti */

	__UDP_MIB_MAX

};

net/ipv4/proc.c

+1 −0
Original line number Diff line number Diff line
@@ -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

};

net/ipv4/udp.c

+9 −3
Original line number Diff line number Diff line
@@ -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) {

net/ipv6/proc.c

+1 −0
Original line number Diff line number Diff line
@@ -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

};

net/ipv6/udp.c

+8 −3
Original line number Diff line number Diff line
@@ -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 */