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Date: Tue, 29 Aug 2017 15:16:01 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: Florian Fainelli <f.fainelli@...il.com>
Cc: David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: [PATCH net-next] neigh: increase queue_len_bytes to match
wmem_default
From: Eric Dumazet <edumazet@...gle.com>
Florian reported UDP xmit drops that could be root caused to the
too small neigh limit.
Current limit is 64 KB, meaning that even a single UDP socket would hit
it, since its default sk_sndbuf comes from net.core.wmem_default
(~212992 bytes on 64bit arches).
Once ARP/ND resolution is in progress, we should allow a little more
packets to be queued, at least for one producer.
Once neigh arp_queue is filled, a rogue socket should hit its sk_sndbuf
limit and either block in sendmsg() or return -EAGAIN.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: Florian Fainelli <f.fainelli@...il.com>
---
Documentation/networking/ip-sysctl.txt | 7 +++++--
include/net/sock.h | 10 ++++++++++
net/core/sock.c | 10 ----------
net/decnet/dn_neigh.c | 2 +-
net/ipv4/arp.c | 2 +-
net/ipv4/tcp_input.c | 2 +-
net/ipv6/ndisc.c | 2 +-
7 files changed, 19 insertions(+), 16 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 6b0bc0f715346a097a6df46e2ba2771359abcd23..b3345d0fe0a67e477a6754848e7fc7be144322d5 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -109,7 +109,10 @@ neigh/default/unres_qlen_bytes - INTEGER
queued for each unresolved address by other network layers.
(added in linux 3.3)
Setting negative value is meaningless and will return error.
- Default: 65536 Bytes(64KB)
+ Default: SK_WMEM_MAX, (same as net.core.wmem_default).
+ Exact value depends on architecture and kernel options,
+ but should be enough to allow queuing 256 packets
+ of medium size.
neigh/default/unres_qlen - INTEGER
The maximum number of packets which may be queued for each
@@ -119,7 +122,7 @@ neigh/default/unres_qlen - INTEGER
unexpected packet loss. The current default value is calculated
according to default value of unres_qlen_bytes and true size of
packet.
- Default: 31
+ Default: 101
mtu_expires - INTEGER
Time, in seconds, that cached PMTU information is kept.
diff --git a/include/net/sock.h b/include/net/sock.h
index 1c2912d433e81b10f3fdc87bcfcbb091570edc03..03a362568357acc7278a318423dd3873103f90ca 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2368,6 +2368,16 @@ bool sk_net_capable(const struct sock *sk, int cap);
void sk_get_meminfo(const struct sock *sk, u32 *meminfo);
+/* Take into consideration the size of the struct sk_buff overhead in the
+ * determination of these values, since that is non-constant across
+ * platforms. This makes socket queueing behavior and performance
+ * not depend upon such differences.
+ */
+#define _SK_MEM_PACKETS 256
+#define _SK_MEM_OVERHEAD SKB_TRUESIZE(256)
+#define SK_WMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
+#define SK_RMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
+
extern __u32 sysctl_wmem_max;
extern __u32 sysctl_rmem_max;
diff --git a/net/core/sock.c b/net/core/sock.c
index dfdd14cac775e9bfcee0085ee32ffcd0ab28b67b..9b7b6bbb2a23e7652a1f34a305f29d49de00bc8c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -307,16 +307,6 @@ static struct lock_class_key af_wlock_keys[AF_MAX];
static struct lock_class_key af_elock_keys[AF_MAX];
static struct lock_class_key af_kern_callback_keys[AF_MAX];
-/* Take into consideration the size of the struct sk_buff overhead in the
- * determination of these values, since that is non-constant across
- * platforms. This makes socket queueing behavior and performance
- * not depend upon such differences.
- */
-#define _SK_MEM_PACKETS 256
-#define _SK_MEM_OVERHEAD SKB_TRUESIZE(256)
-#define SK_WMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
-#define SK_RMEM_MAX (_SK_MEM_OVERHEAD * _SK_MEM_PACKETS)
-
/* Run time adjustable parameters. */
__u32 sysctl_wmem_max __read_mostly = SK_WMEM_MAX;
EXPORT_SYMBOL(sysctl_wmem_max);
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index 21dedf6fd0f76dec22b2b3685beb89cfefea7ded..22bf0b95d6edc3c27ef3a99d27cb70a1551e3e0e 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -94,7 +94,7 @@ struct neigh_table dn_neigh_table = {
[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
- [NEIGH_VAR_QUEUE_LEN_BYTES] = 64*1024,
+ [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
[NEIGH_VAR_PROXY_QLEN] = 0,
[NEIGH_VAR_ANYCAST_DELAY] = 0,
[NEIGH_VAR_PROXY_DELAY] = 0,
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 8b52179ddc6e54eabf6d3c2ed0132083228680bb..7c45b8896709815c5dde5972fd57cb5c3bcb2648 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -171,7 +171,7 @@ struct neigh_table arp_tbl = {
[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
- [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
+ [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
[NEIGH_VAR_PROXY_QLEN] = 64,
[NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
[NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 568ccfd6dd371d88136ffabe5cfcc36f099786b6..7616cd76f6f6a62f395da897baef2c66c0098193 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6086,9 +6086,9 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
struct tcp_sock *tp = tcp_sk(sk);
struct net *net = sock_net(sk);
struct sock *fastopen_sk = NULL;
- struct dst_entry *dst = NULL;
struct request_sock *req;
bool want_cookie = false;
+ struct dst_entry *dst;
struct flowi fl;
/* TW buckets are converted to open requests without
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 5e338eb89509b1df6ebd060f8bd19fcb4b86fe05..266a530414d7be4f1e7be922e465bbab46f7cbac 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -127,7 +127,7 @@ struct neigh_table nd_tbl = {
[NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,
[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
- [NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
+ [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
[NEIGH_VAR_PROXY_QLEN] = 64,
[NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
[NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
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