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udp: Increment UDP_MIB_IGNOREDMULTI for arriving unmatched multicasts

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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 <rick.jones2@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Rick Jones 2014-11-06 10:37:54 -08:00 committed by David S. Miller
parent f46ad73ac6
commit 36cbb2452c
5 changed files with 20 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/uapi/linux/snmp.h
View File

@ -156,6 +156,7 @@ enum
UDP_MIB_RCVBUFERRORS, /* RcvbufErrors */
UDP_MIB_SNDBUFERRORS, /* SndbufErrors */
UDP_MIB_CSUMERRORS, /* InCsumErrors */
UDP_MIB_IGNOREDMULTI, /* IgnoredMulti */
__UDP_MIB_MAX
};

1
net/ipv4/proc.c
View File

@ -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
};

12
net/ipv4/udp.c
View File

@ -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 @@ start_lookup:
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 @@ start_lookup:
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) {

1
net/ipv6/proc.c
View File

@ -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
};

11
net/ipv6/udp.c
View File

@ -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 @@ start_lookup:
(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 @@ start_lookup:
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 */