From b582ef0990d457f7ce8ccf827af51a575ca0b4a6 Mon Sep 17 00:00:00 2001 From: Or Gerlitz Date: Mon, 20 Jan 2014 13:59:19 +0200 Subject: [PATCH] net: Add GRO support for UDP encapsulating protocols Add GRO handlers for protocols that do UDP encapsulation, with the intent of being able to coalesce packets which encapsulate packets belonging to the same TCP session. For GRO purposes, the destination UDP port takes the role of the ether type field in the ethernet header or the next protocol in the IP header. The UDP GRO handler will only attempt to coalesce packets whose destination port is registered to have gro handler. Use a mark on the skb GRO CB data to disallow (flush) running the udp gro receive code twice on a packet. This solves the problem of udp encapsulated packets whose inner VM packet is udp and happen to carry a port which has registered offloads. Signed-off-by: Shlomo Pongratz Signed-off-by: Or Gerlitz Signed-off-by: David S. Miller --- include/linux/netdevice.h | 10 +++- include/net/protocol.h | 3 + net/core/dev.c | 1 + net/ipv4/udp_offload.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 156 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 83ce2aee65e6..c31022980e18 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1675,7 +1675,10 @@ struct napi_gro_cb { unsigned long age; /* Used in ipv6_gro_receive() */ - int proto; + u16 proto; + + /* Used in udp_gro_receive */ + u16 udp_mark; /* used to support CHECKSUM_COMPLETE for tunneling protocols */ __wsum csum; @@ -1714,6 +1717,11 @@ struct packet_offload { struct list_head list; }; +struct udp_offload { + __be16 port; + struct offload_callbacks callbacks; +}; + /* often modified stats are per cpu, other are shared (netdev->stats) */ struct pcpu_sw_netstats { u64 rx_packets; diff --git a/include/net/protocol.h b/include/net/protocol.h index 0e5f8665d7fb..a7e986b08147 100644 --- a/include/net/protocol.h +++ b/include/net/protocol.h @@ -108,6 +108,9 @@ int inet_del_offload(const struct net_offload *prot, unsigned char num); void inet_register_protosw(struct inet_protosw *p); void inet_unregister_protosw(struct inet_protosw *p); +int udp_add_offload(struct udp_offload *prot); +void udp_del_offload(struct udp_offload *prot); + #if IS_ENABLED(CONFIG_IPV6) int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char num); int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char num); diff --git a/net/core/dev.c b/net/core/dev.c index a578af589198..da92305c344f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3893,6 +3893,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff NAPI_GRO_CB(skb)->same_flow = 0; NAPI_GRO_CB(skb)->flush = 0; NAPI_GRO_CB(skb)->free = 0; + NAPI_GRO_CB(skb)->udp_mark = 0; pp = ptype->callbacks.gro_receive(&napi->gro_list, skb); break; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 79c62bdcd3c5..ee853c55deea 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -14,6 +14,15 @@ #include #include +static DEFINE_SPINLOCK(udp_offload_lock); +static struct udp_offload_priv *udp_offload_base __read_mostly; + +struct udp_offload_priv { + struct udp_offload *offload; + struct rcu_head rcu; + struct udp_offload_priv __rcu *next; +}; + static int udp4_ufo_send_check(struct sk_buff *skb) { if (!pskb_may_pull(skb, sizeof(struct udphdr))) @@ -89,10 +98,144 @@ out: return segs; } +int udp_add_offload(struct udp_offload *uo) +{ + struct udp_offload_priv **head = &udp_offload_base; + struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_KERNEL); + + if (!new_offload) + return -ENOMEM; + + new_offload->offload = uo; + + spin_lock(&udp_offload_lock); + rcu_assign_pointer(new_offload->next, rcu_dereference(*head)); + rcu_assign_pointer(*head, rcu_dereference(new_offload)); + spin_unlock(&udp_offload_lock); + + return 0; +} +EXPORT_SYMBOL(udp_add_offload); + +static void udp_offload_free_routine(struct rcu_head *head) +{ + struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu); + kfree(ou_priv); +} + +void udp_del_offload(struct udp_offload *uo) +{ + struct udp_offload_priv __rcu **head = &udp_offload_base; + struct udp_offload_priv *uo_priv; + + spin_lock(&udp_offload_lock); + + uo_priv = rcu_dereference(*head); + for (; uo_priv != NULL; + uo_priv = rcu_dereference(*head)) { + + if (uo_priv->offload == uo) { + rcu_assign_pointer(*head, rcu_dereference(uo_priv->next)); + goto unlock; + } + head = &uo_priv->next; + } + pr_warn("udp_del_offload: didn't find offload for port %d\n", htons(uo->port)); +unlock: + spin_unlock(&udp_offload_lock); + if (uo_priv != NULL) + call_rcu(&uo_priv->rcu, udp_offload_free_routine); +} +EXPORT_SYMBOL(udp_del_offload); + +static struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + struct udp_offload_priv *uo_priv; + struct sk_buff *p, **pp = NULL; + struct udphdr *uh, *uh2; + unsigned int hlen, off; + int flush = 1; + + if (NAPI_GRO_CB(skb)->udp_mark || + (!skb->encapsulation && skb->ip_summed != CHECKSUM_COMPLETE)) + goto out; + + /* mark that this skb passed once through the udp gro layer */ + NAPI_GRO_CB(skb)->udp_mark = 1; + + off = skb_gro_offset(skb); + hlen = off + sizeof(*uh); + uh = skb_gro_header_fast(skb, off); + if (skb_gro_header_hard(skb, hlen)) { + uh = skb_gro_header_slow(skb, hlen, off); + if (unlikely(!uh)) + goto out; + } + + rcu_read_lock(); + uo_priv = rcu_dereference(udp_offload_base); + for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { + if (uo_priv->offload->port == uh->dest && + uo_priv->offload->callbacks.gro_receive) + goto unflush; + } + goto out_unlock; + +unflush: + flush = 0; + + for (p = *head; p; p = p->next) { + if (!NAPI_GRO_CB(p)->same_flow) + continue; + + uh2 = (struct udphdr *)(p->data + off); + if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) { + NAPI_GRO_CB(p)->same_flow = 0; + continue; + } + } + + skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ + pp = uo_priv->offload->callbacks.gro_receive(head, skb); + +out_unlock: + rcu_read_unlock(); +out: + NAPI_GRO_CB(skb)->flush |= flush; + return pp; +} + +static int udp_gro_complete(struct sk_buff *skb, int nhoff) +{ + struct udp_offload_priv *uo_priv; + __be16 newlen = htons(skb->len - nhoff); + struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); + int err = -ENOSYS; + + uh->len = newlen; + + rcu_read_lock(); + + uo_priv = rcu_dereference(udp_offload_base); + for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) { + if (uo_priv->offload->port == uh->dest && + uo_priv->offload->callbacks.gro_complete) + break; + } + + if (uo_priv != NULL) + err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr)); + + rcu_read_unlock(); + return err; +} + static const struct net_offload udpv4_offload = { .callbacks = { .gso_send_check = udp4_ufo_send_check, .gso_segment = udp4_ufo_fragment, + .gro_receive = udp_gro_receive, + .gro_complete = udp_gro_complete, }, }; -- 2.11.0