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authorPaolo Abeni <pabeni@redhat.com>2018-11-07 14:38:29 +0300
committerDavid S. Miller <davem@davemloft.net>2018-11-08 03:23:04 +0300
commite20cf8d3f1f763ad28a9cb3b41305b8a8a42653e (patch)
treee2e368163d1ee2b19b75869cd06a04e32d13c8d6 /net/ipv4/udp_offload.c
parent60fb9567bf30937e6bedfa939d7c8fd4ee6a1b1c (diff)
downloadlinux-e20cf8d3f1f763ad28a9cb3b41305b8a8a42653e.tar.xz
udp: implement GRO for plain UDP sockets.
This is the RX counterpart of commit bec1f6f69736 ("udp: generate gso with UDP_SEGMENT"). When UDP_GRO is enabled, such socket is also eligible for GRO in the rx path: UDP segments directed to such socket are assembled into a larger GSO_UDP_L4 packet. The core UDP GRO support is enabled with setsockopt(UDP_GRO). Initial benchmark numbers: Before: udp rx: 1079 MB/s 769065 calls/s After: udp rx: 1466 MB/s 24877 calls/s This change introduces a side effect in respect to UDP tunnels: after a UDP tunnel creation, now the kernel performs a lookup per ingress UDP packet, while before such lookup happened only if the ingress packet carried a valid internal header csum. rfc v2 -> rfc v3: - fixed typos in macro name and comments - really enforce UDP_GRO_CNT_MAX, instead of UDP_GRO_CNT_MAX + 1 - acquire socket lock in UDP_GRO setsockopt rfc v1 -> rfc v2: - use a new option to enable UDP GRO - use static keys to protect the UDP GRO socket lookup Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/udp_offload.c')
-rw-r--r--net/ipv4/udp_offload.c109
1 files changed, 87 insertions, 22 deletions
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 802f2bc00d69..0646d61f4fa8 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -343,6 +343,54 @@ out:
return segs;
}
+#define UDP_GRO_CNT_MAX 64
+static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
+ struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+ struct sk_buff *pp = NULL;
+ struct udphdr *uh2;
+ struct sk_buff *p;
+
+ /* requires non zero csum, for symmetry with GSO */
+ if (!uh->check) {
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+ }
+
+ /* pull encapsulating udp header */
+ skb_gro_pull(skb, sizeof(struct udphdr));
+ skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
+
+ list_for_each_entry(p, head, list) {
+ if (!NAPI_GRO_CB(p)->same_flow)
+ continue;
+
+ uh2 = udp_hdr(p);
+
+ /* Match ports only, as csum is always non zero */
+ if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
+ NAPI_GRO_CB(p)->same_flow = 0;
+ continue;
+ }
+
+ /* Terminate the flow on len mismatch or if it grow "too much".
+ * Under small packet flood GRO count could elsewhere grow a lot
+ * leading to execessive truesize values
+ */
+ if (!skb_gro_receive(p, skb) &&
+ NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
+ pp = p;
+ else if (uh->len != uh2->len)
+ pp = p;
+
+ return pp;
+ }
+
+ /* mismatch, but we never need to flush */
+ return NULL;
+}
+
struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, udp_lookup_t lookup)
{
@@ -353,23 +401,27 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
int flush = 1;
struct sock *sk;
+ rcu_read_lock();
+ sk = (*lookup)(skb, uh->source, uh->dest);
+ if (!sk)
+ goto out_unlock;
+
+ if (udp_sk(sk)->gro_enabled) {
+ pp = call_gro_receive(udp_gro_receive_segment, head, skb);
+ rcu_read_unlock();
+ return pp;
+ }
+
if (NAPI_GRO_CB(skb)->encap_mark ||
(skb->ip_summed != CHECKSUM_PARTIAL &&
NAPI_GRO_CB(skb)->csum_cnt == 0 &&
- !NAPI_GRO_CB(skb)->csum_valid))
- goto out;
+ !NAPI_GRO_CB(skb)->csum_valid) ||
+ !udp_sk(sk)->gro_receive)
+ goto out_unlock;
/* mark that this skb passed once through the tunnel gro layer */
NAPI_GRO_CB(skb)->encap_mark = 1;
- rcu_read_lock();
- sk = (*lookup)(skb, uh->source, uh->dest);
-
- if (sk && udp_sk(sk)->gro_receive)
- goto unflush;
- goto out_unlock;
-
-unflush:
flush = 0;
list_for_each_entry(p, head, list) {
@@ -394,7 +446,6 @@ unflush:
out_unlock:
rcu_read_unlock();
-out:
skb_gro_flush_final(skb, pp, flush);
return pp;
}
@@ -427,6 +478,19 @@ flush:
return NULL;
}
+static int udp_gro_complete_segment(struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+
+ skb->csum_start = (unsigned char *)uh - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
+ skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
+ return 0;
+}
+
int udp_gro_complete(struct sk_buff *skb, int nhoff,
udp_lookup_t lookup)
{
@@ -437,16 +501,21 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
uh->len = newlen;
- /* Set encapsulation before calling into inner gro_complete() functions
- * to make them set up the inner offsets.
- */
- skb->encapsulation = 1;
-
rcu_read_lock();
sk = (*lookup)(skb, uh->source, uh->dest);
- if (sk && udp_sk(sk)->gro_complete)
+ if (sk && udp_sk(sk)->gro_enabled) {
+ err = udp_gro_complete_segment(skb);
+ } else if (sk && udp_sk(sk)->gro_complete) {
+ skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
+ : SKB_GSO_UDP_TUNNEL;
+
+ /* Set encapsulation before calling into inner gro_complete()
+ * functions to make them set up the inner offsets.
+ */
+ skb->encapsulation = 1;
err = udp_sk(sk)->gro_complete(sk, skb,
nhoff + sizeof(struct udphdr));
+ }
rcu_read_unlock();
if (skb->remcsum_offload)
@@ -461,13 +530,9 @@ static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
const struct iphdr *iph = ip_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
- if (uh->check) {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ if (uh->check)
uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
iph->daddr, 0);
- } else {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
- }
return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
}