ipv6: introduce ipv6_make_skb

This commit is very similar to
commit 1c32c5ad6fac8cee1a77449f5abf211e911ff830
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Tue Mar 1 02:36:47 2011 +0000

    inet: Add ip_make_skb and ip_finish_skb

It adds IPv6 version of the helpers ip6_make_skb and ip6_finish_skb.

The job of ip6_make_skb is to collect messages into an ipv6 packet
and poplulate ipv6 eader.  The job of ip6_finish_skb is to transmit
the generated skb.  Together they replicated the job of
ip6_push_pending_frames() while also provide the capability to be
called independently.  This will be needed to add lockless UDP sendmsg
support.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 4292929392b0127479c49c5da3bb33f053f4428c..8027ca53e31f5903e055c425fef097ca9ccaa173 100644 (file)
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -788,6 +788,25 @@ int ip6_push_pending_frames(struct sock *sk);
 
 void ip6_flush_pending_frames(struct sock *sk);
 
+int ip6_send_skb(struct sk_buff *skb);
+
+struct sk_buff *__ip6_make_skb(struct sock *sk, struct sk_buff_head *queue,
+                              struct inet_cork_full *cork,
+                              struct inet6_cork *v6_cork);
+struct sk_buff *ip6_make_skb(struct sock *sk,
+                            int getfrag(void *from, char *to, int offset,
+                                        int len, int odd, struct sk_buff *skb),
+                            void *from, int length, int transhdrlen,
+                            int hlimit, int tclass, struct ipv6_txoptions *opt,
+                            struct flowi6 *fl6, struct rt6_info *rt,
+                            unsigned int flags, int dontfrag);
+
+static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
+{
+       return __ip6_make_skb(sk, &sk->sk_write_queue, &inet_sk(sk)->cork,
+                             &inet6_sk(sk)->cork);
+}
+
 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi6 *fl6);
 struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6,
                                      const struct in6_addr *final_dst);

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1b66453a695d12ea84830108dda13dcf0fe8bb5b..b89d3c27dac7a5001084a7430b0c8e2a5b7a3dc2 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1564,22 +1564,23 @@ static void ip6_cork_release(struct inet_cork_full *cork,
        memset(&cork->fl, 0, sizeof(cork->fl));
 }
 
-int ip6_push_pending_frames(struct sock *sk)
+struct sk_buff *__ip6_make_skb(struct sock *sk,
+                              struct sk_buff_head *queue,
+                              struct inet_cork_full *cork,
+                              struct inet6_cork *v6_cork)
 {
        struct sk_buff *skb, *tmp_skb;
        struct sk_buff **tail_skb;
        struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
-       struct inet_sock *inet = inet_sk(sk);
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct net *net = sock_net(sk);
        struct ipv6hdr *hdr;
-       struct ipv6_txoptions *opt = np->cork.opt;
-       struct rt6_info *rt = (struct rt6_info *)inet->cork.base.dst;
-       struct flowi6 *fl6 = &inet->cork.fl.u.ip6;
+       struct ipv6_txoptions *opt = v6_cork->opt;
+       struct rt6_info *rt = (struct rt6_info *)cork->base.dst;
+       struct flowi6 *fl6 = &cork->fl.u.ip6;
        unsigned char proto = fl6->flowi6_proto;
-       int err = 0;
 
-       skb = __skb_dequeue(&sk->sk_write_queue);
+       skb = __skb_dequeue(queue);
        if (skb == NULL)
                goto out;
        tail_skb = &(skb_shinfo(skb)->frag_list);
@@ -1587,7 +1588,7 @@ int ip6_push_pending_frames(struct sock *sk)
        /* move skb->data to ip header from ext header */
        if (skb->data < skb_network_header(skb))
                __skb_pull(skb, skb_network_offset(skb));
-       while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
+       while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
                __skb_pull(tmp_skb, skb_network_header_len(skb));
                *tail_skb = tmp_skb;
                tail_skb = &(tmp_skb->next);
@@ -1612,10 +1613,10 @@ int ip6_push_pending_frames(struct sock *sk)
        skb_reset_network_header(skb);
        hdr = ipv6_hdr(skb);
 
-       ip6_flow_hdr(hdr, np->cork.tclass,
+       ip6_flow_hdr(hdr, v6_cork->tclass,
                     ip6_make_flowlabel(net, skb, fl6->flowlabel,
                                        np->autoflowlabel));
-       hdr->hop_limit = np->cork.hop_limit;
+       hdr->hop_limit = v6_cork->hop_limit;
        hdr->nexthdr = proto;
        hdr->saddr = fl6->saddr;
        hdr->daddr = *final_dst;
@@ -1632,25 +1633,45 @@ int ip6_push_pending_frames(struct sock *sk)
                ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
        }
 
+       ip6_cork_release(cork, v6_cork);
+out:
+       return skb;
+}
+
+int ip6_send_skb(struct sk_buff *skb)
+{
+       struct net *net = sock_net(skb->sk);
+       struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
+       int err;
+
        err = ip6_local_out(skb);
        if (err) {
                if (err > 0)
                        err = net_xmit_errno(err);
                if (err)
-                       goto error;
+                       IP6_INC_STATS(net, rt->rt6i_idev,
+                                     IPSTATS_MIB_OUTDISCARDS);
        }
 
-out:
-       ip6_cork_release(&inet->cork, &np->cork);
        return err;
-error:
-       IP6_INC_STATS(net, rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);
-       goto out;
+}
+
+int ip6_push_pending_frames(struct sock *sk)
+{
+       struct sk_buff *skb;
+
+       skb = ip6_finish_skb(sk);
+       if (!skb)
+               return 0;
+
+       return ip6_send_skb(skb);
 }
 EXPORT_SYMBOL_GPL(ip6_push_pending_frames);
 
 static void __ip6_flush_pending_frames(struct sock *sk,
-                                      struct sk_buff_head *queue)
+                                      struct sk_buff_head *queue,
+                                      struct inet_cork_full *cork,
+                                      struct inet6_cork *v6_cork)
 {
        struct sk_buff *skb;
 
@@ -1661,11 +1682,55 @@ static void __ip6_flush_pending_frames(struct sock *sk,
                kfree_skb(skb);
        }
 
-       ip6_cork_release(&inet_sk(sk)->cork, &inet6_sk(sk)->cork);
+       ip6_cork_release(cork, v6_cork);
 }
 
 void ip6_flush_pending_frames(struct sock *sk)
 {
-       __ip6_flush_pending_frames(sk, &sk->sk_write_queue);
+       __ip6_flush_pending_frames(sk, &sk->sk_write_queue,
+                                  &inet_sk(sk)->cork, &inet6_sk(sk)->cork);
 }
 EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
+
+struct sk_buff *ip6_make_skb(struct sock *sk,
+                            int getfrag(void *from, char *to, int offset,
+                                        int len, int odd, struct sk_buff *skb),
+                            void *from, int length, int transhdrlen,
+                            int hlimit, int tclass,
+                            struct ipv6_txoptions *opt, struct flowi6 *fl6,
+                            struct rt6_info *rt, unsigned int flags,
+                            int dontfrag)
+{
+       struct inet_cork_full cork;
+       struct inet6_cork v6_cork;
+       struct sk_buff_head queue;
+       int exthdrlen = (opt ? opt->opt_flen : 0);
+       int err;
+
+       if (flags & MSG_PROBE)
+               return NULL;
+
+       __skb_queue_head_init(&queue);
+
+       cork.base.flags = 0;
+       cork.base.addr = 0;
+       cork.base.opt = NULL;
+       v6_cork.opt = NULL;
+       err = ip6_setup_cork(sk, &cork, &v6_cork, hlimit, tclass, opt, rt, fl6);
+       if (err)
+               return ERR_PTR(err);
+
+       if (dontfrag < 0)
+               dontfrag = inet6_sk(sk)->dontfrag;
+
+       err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
+                               &current->task_frag, getfrag, from,
+                               length + exthdrlen, transhdrlen + exthdrlen,
+                               flags, dontfrag);
+       if (err) {
+               __ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
+               return ERR_PTR(err);
+       }
+
+       return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
+}