2 files changed, 100 insertions, 0 deletions

diff --git a/include/net/protocol.h b/include/net/protocol.h
index 8d024d7cb741..cb2965aa1b62 100644
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -39,6 +39,9 @@ struct net_protocol {
         int                     (*gso_send_check)(struct sk_buff *skb);
         struct sk_buff         *(*gso_segment)(struct sk_buff *skb,
                                                int features);
+        struct sk_buff        **(*gro_receive)(struct sk_buff **head,
+                                               struct sk_buff *skb);
+        int                     (*gro_complete)(struct sk_buff *skb);
         unsigned int            no_policy:1,
                                 netns_ok:1;
 };
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index fe03048c130d..a85595307fa7 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -94,6 +94,7 @@
 #include <linux/igmp.h>
 #include <linux/inetdevice.h>
 #include <linux/netdevice.h>
+#include <net/checksum.h>
 #include <net/ip.h>
 #include <net/protocol.h>
 #include <net/arp.h>
@@ -1241,6 +1242,100 @@ out:
         return segs;
 }
 
+static struct sk_buff **inet_gro_receive(struct sk_buff **head,
+                                         struct sk_buff *skb)
+{
+        struct net_protocol *ops;
+        struct sk_buff **pp = NULL;
+        struct sk_buff *p;
+        struct iphdr *iph;
+        int flush = 1;
+        int proto;
+        int id;
+
+        if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+                goto out;
+
+        iph = ip_hdr(skb);
+        proto = iph->protocol & (MAX_INET_PROTOS - 1);
+
+        rcu_read_lock();
+        ops = rcu_dereference(inet_protos[proto]);
+        if (!ops || !ops->gro_receive)
+                goto out_unlock;
+
+        if (iph->version != 4 || iph->ihl != 5)
+                goto out_unlock;
+
+        if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
+                goto out_unlock;
+
+        flush = ntohs(iph->tot_len) != skb->len ||
+                iph->frag_off != htons(IP_DF);
+        id = ntohs(iph->id);
+
+        for (p = *head; p; p = p->next) {
+                struct iphdr *iph2;
+
+                if (!NAPI_GRO_CB(p)->same_flow)
+                        continue;
+
+                iph2 = ip_hdr(p);
+
+                if (iph->protocol != iph2->protocol ||
+                    iph->tos != iph2->tos ||
+                    memcmp(&iph->saddr, &iph2->saddr, 8)) {
+                        NAPI_GRO_CB(p)->same_flow = 0;
+                        continue;
+                }
+
+                /* All fields must match except length and checksum. */
+                NAPI_GRO_CB(p)->flush |=
+                        memcmp(&iph->frag_off, &iph2->frag_off, 4) ||
+                        (u16)(ntohs(iph2->id) + NAPI_GRO_CB(p)->count) != id;
+
+                NAPI_GRO_CB(p)->flush |= flush;
+        }
+
+        NAPI_GRO_CB(skb)->flush |= flush;
+        __skb_pull(skb, sizeof(*iph));
+        skb_reset_transport_header(skb);
+
+        pp = ops->gro_receive(head, skb);
+
+out_unlock:
+        rcu_read_unlock();
+
+out:
+        NAPI_GRO_CB(skb)->flush |= flush;
+
+        return pp;
+}
+
+static int inet_gro_complete(struct sk_buff *skb)
+{
+        struct net_protocol *ops;
+        struct iphdr *iph = ip_hdr(skb);
+        int proto = iph->protocol & (MAX_INET_PROTOS - 1);
+        int err = -ENOSYS;
+        __be16 newlen = htons(skb->len - skb_network_offset(skb));
+
+        csum_replace2(&iph->check, iph->tot_len, newlen);
+        iph->tot_len = newlen;
+
+        rcu_read_lock();
+        ops = rcu_dereference(inet_protos[proto]);
+        if (WARN_ON(!ops || !ops->gro_complete))
+                goto out_unlock;
+
+        err = ops->gro_complete(skb);
+
+out_unlock:
+        rcu_read_unlock();
+
+        return err;
+}
+
 int inet_ctl_sock_create(struct sock **sk, unsigned short family,
                          unsigned short type, unsigned char protocol,
                          struct net *net)
@@ -1407,6 +1502,8 @@ static struct packet_type ip_packet_type = {
         .func = ip_rcv,
         .gso_send_check = inet_gso_send_check,
         .gso_segment = inet_gso_segment,
+        .gro_receive = inet_gro_receive,
+        .gro_complete = inet_gro_complete,
 };
 
 static int __init inet_init(void)