net: ipv4: avoid repeated calls to ip_skb_dst_mtu helper

[firefly-linux-kernel-4.4.55.git] / net / ipv4 / ip_output.c

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index c65b93a7b7113660d9f946128c0a4acee810de0f..d6dd8ba044414b1ca2c4977e68387eba8d29e0dc 100644 (file)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -83,6 +83,10 @@
 int sysctl_ip_default_ttl __read_mostly = IPDEFTTL;
 EXPORT_SYMBOL(sysctl_ip_default_ttl);
 
+static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+                      unsigned int mtu,
+                      int (*output)(struct sock *, struct sk_buff *));
+
 /* Generate a checksum for an outgoing IP datagram. */
 void ip_send_check(struct iphdr *iph)
 {
@@ -91,7 +95,7 @@ void ip_send_check(struct iphdr *iph)
 }
 EXPORT_SYMBOL(ip_send_check);
 
-int __ip_local_out_sk(struct sock *sk, struct sk_buff *skb)
+static int __ip_local_out_sk(struct sock *sk, struct sk_buff *skb)
 {
        struct iphdr *iph = ip_hdr(skb);
 
@@ -216,7 +220,8 @@ static inline int ip_finish_output2(struct sock *sk, struct sk_buff *skb)
        return -EINVAL;
 }
 
-static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb)
+static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb,
+                               unsigned int mtu)
 {
        netdev_features_t features;
        struct sk_buff *segs;
@@ -224,7 +229,7 @@ static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb)
 
        /* common case: locally created skb or seglen is <= mtu */
        if (((IPCB(skb)->flags & IPSKB_FORWARDED) == 0) ||
-             skb_gso_network_seglen(skb) <= ip_skb_dst_mtu(skb))
+             skb_gso_network_seglen(skb) <= mtu)
                return ip_finish_output2(sk, skb);
 
        /* Slowpath -  GSO segment length is exceeding the dst MTU.
@@ -248,7 +253,7 @@ static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb)
                int err;
 
                segs->next = NULL;
-               err = ip_fragment(sk, segs, ip_finish_output2);
+               err = ip_fragment(sk, segs, mtu, ip_finish_output2);
 
                if (err && ret == 0)
                        ret = err;
@@ -260,6 +265,8 @@ static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb)
 
 static int ip_finish_output(struct sock *sk, struct sk_buff *skb)
 {
+       unsigned int mtu;
+
 #if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
        /* Policy lookup after SNAT yielded a new policy */
        if (skb_dst(skb)->xfrm) {
@@ -267,11 +274,12 @@ static int ip_finish_output(struct sock *sk, struct sk_buff *skb)
                return dst_output_sk(sk, skb);
        }
 #endif
+       mtu = ip_skb_dst_mtu(skb);
        if (skb_is_gso(skb))
-               return ip_finish_output_gso(sk, skb);
+               return ip_finish_output_gso(sk, skb, mtu);
 
-       if (skb->len > ip_skb_dst_mtu(skb))
-               return ip_fragment(sk, skb, ip_finish_output2);
+       if (skb->len > mtu)
+               return ip_fragment(sk, skb, mtu, ip_finish_output2);
 
        return ip_finish_output2(sk, skb);
 }
@@ -478,6 +486,28 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
        skb_copy_secmark(to, from);
 }
 
+static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+                      unsigned int mtu,
+                      int (*output)(struct sock *, struct sk_buff *))
+{
+       struct iphdr *iph = ip_hdr(skb);
+
+       if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
+                    (IPCB(skb)->frag_max_size &&
+                     IPCB(skb)->frag_max_size > mtu))) {
+               struct rtable *rt = skb_rtable(skb);
+               struct net_device *dev = rt->dst.dev;
+
+               IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
+               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+                         htonl(mtu));
+               kfree_skb(skb);
+               return -EMSGSIZE;
+       }
+
+       return ip_do_fragment(sk, skb, output);
+}
+
 /*
  *     This IP datagram is too large to be sent in one piece.  Break it up into
  *     smaller pieces (each of size equal to IP header plus
@@ -485,8 +515,8 @@ static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
  *     single device frame, and queue such a frame for sending.
  */
 
-int ip_fragment(struct sock *sk, struct sk_buff *skb,
-               int (*output)(struct sock *, struct sk_buff *))
+int ip_do_fragment(struct sock *sk, struct sk_buff *skb,
+                  int (*output)(struct sock *, struct sk_buff *))
 {
        struct iphdr *iph;
        int ptr;
@@ -507,15 +537,6 @@ int ip_fragment(struct sock *sk, struct sk_buff *skb,
        iph = ip_hdr(skb);
 
        mtu = ip_skb_dst_mtu(skb);
-       if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
-                    (IPCB(skb)->frag_max_size &&
-                     IPCB(skb)->frag_max_size > mtu))) {
-               IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
-               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
-                         htonl(mtu));
-               kfree_skb(skb);
-               return -EMSGSIZE;
-       }
 
        /*
         *      Setup starting values.
@@ -751,7 +772,7 @@ fail:
        IP_INC_STATS(dev_net(dev), IPSTATS_MIB_FRAGFAILS);
        return err;
 }
-EXPORT_SYMBOL(ip_fragment);
+EXPORT_SYMBOL(ip_do_fragment);
 
 int
 ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
@@ -1217,11 +1238,9 @@ ssize_t  ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
        }
 
        while (size > 0) {
-               int i;
-
-               if (skb_is_gso(skb))
+               if (skb_is_gso(skb)) {
                        len = size;
-               else {
+               } else {
 
                        /* Check if the remaining data fits into current packet. */
                        len = mtu - skb->len;
@@ -1273,15 +1292,10 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
                        continue;
                }
 
-               i = skb_shinfo(skb)->nr_frags;
                if (len > size)
                        len = size;
-               if (skb_can_coalesce(skb, i, page, offset)) {
-                       skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
-               } else if (i < MAX_SKB_FRAGS) {
-                       get_page(page);
-                       skb_fill_page_desc(skb, i, page, offset, len);
-               } else {
+
+               if (skb_append_pagefrags(skb, page, offset, len)) {
                        err = -EMSGSIZE;
                        goto error;
                }