udp: Switch to ip_finish_skb

This patch converts UDP to use the new ip_finish_skb API.  This
would then allows us to more easily use ip_make_skb which allows
UDP to run without a socket lock.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/udp.h b/include/net/udp.h
index e82f3a8..67ea6fc 100644 (file)
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -144,6 +144,17 @@ static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
        return csum;
 }
 
+static inline __wsum udp_csum(struct sk_buff *skb)
+{
+       __wsum csum = csum_partial(skb_transport_header(skb),
+                                  sizeof(struct udphdr), skb->csum);
+
+       for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
+               csum = csum_add(csum, skb->csum);
+       }
+       return csum;
+}
+
 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
 static inline void udp_lib_hash(struct sock *sk)
 {

diff --git a/include/net/udplite.h b/include/net/udplite.h
index afdffe6..673a024 100644 (file)
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -115,6 +115,18 @@ static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
        return csum;
 }
 
+static inline __wsum udplite_csum(struct sk_buff *skb)
+{
+       struct sock *sk = skb->sk;
+       int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
+       const int off = skb_transport_offset(skb);
+       const int len = skb->len - off;
+
+       skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
+
+       return skb_checksum(skb, off, min(cscov, len), 0);
+}
+
 extern void    udplite4_register(void);
 extern int     udplite_get_port(struct sock *sk, unsigned short snum,
                        int (*scmp)(const struct sock *, const struct sock *));

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d37baaa..61c22ee 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -663,75 +663,72 @@ void udp_flush_pending_frames(struct sock *sk)
 EXPORT_SYMBOL(udp_flush_pending_frames);
 
 /**
- *     udp4_hwcsum_outgoing  -  handle outgoing HW checksumming
- *     @sk:    socket we are sending on
+ *     udp4_hwcsum  -  handle outgoing HW checksumming
  *     @skb:   sk_buff containing the filled-in UDP header
  *             (checksum field must be zeroed out)
+ *     @src:   source IP address
+ *     @dst:   destination IP address
  */
-static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
-                                __be32 src, __be32 dst, int len)
+static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
 {
-       unsigned int offset;
        struct udphdr *uh = udp_hdr(skb);
+       struct sk_buff *frags = skb_shinfo(skb)->frag_list;
+       int offset = skb_transport_offset(skb);
+       int len = skb->len - offset;
+       int hlen = len;
        __wsum csum = 0;
 
-       if (skb_queue_len(&sk->sk_write_queue) == 1) {
+       if (!frags) {
                /*
                 * Only one fragment on the socket.
                 */
                skb->csum_start = skb_transport_header(skb) - skb->head;
                skb->csum_offset = offsetof(struct udphdr, check);
-               uh->check = ~csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, 0);
+               uh->check = ~csum_tcpudp_magic(src, dst, len,
+                                              IPPROTO_UDP, 0);
        } else {
                /*
                 * HW-checksum won't work as there are two or more
                 * fragments on the socket so that all csums of sk_buffs
                 * should be together
                 */
-               offset = skb_transport_offset(skb);
-               skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+               do {
+                       csum = csum_add(csum, frags->csum);
+                       hlen -= frags->len;
+               } while ((frags = frags->next));
 
+               csum = skb_checksum(skb, offset, hlen, csum);
                skb->ip_summed = CHECKSUM_NONE;
 
-               skb_queue_walk(&sk->sk_write_queue, skb) {
-                       csum = csum_add(csum, skb->csum);
-               }
-
                uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
                if (uh->check == 0)
                        uh->check = CSUM_MANGLED_0;
        }
 }
 
-/*
- * Push out all pending data as one UDP datagram. Socket is locked.
- */
-static int udp_push_pending_frames(struct sock *sk)
+static int udp_send_skb(struct sk_buff *skb, __be32 daddr, __be32 dport)
 {
-       struct udp_sock  *up = udp_sk(sk);
+       struct sock *sk = skb->sk;
        struct inet_sock *inet = inet_sk(sk);
-       struct flowi *fl = &inet->cork.fl;
-       struct sk_buff *skb;
        struct udphdr *uh;
+       struct rtable *rt = (struct rtable *)skb_dst(skb);
        int err = 0;
        int is_udplite = IS_UDPLITE(sk);
+       int offset = skb_transport_offset(skb);
+       int len = skb->len - offset;
        __wsum csum = 0;
 
-       /* Grab the skbuff where UDP header space exists. */
-       if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
-               goto out;
-
        /*
         * Create a UDP header
         */
        uh = udp_hdr(skb);
-       uh->source = fl->fl_ip_sport;
-       uh->dest = fl->fl_ip_dport;
-       uh->len = htons(up->len);
+       uh->source = inet->inet_sport;
+       uh->dest = dport;
+       uh->len = htons(len);
        uh->check = 0;
 
        if (is_udplite)                                  /*     UDP-Lite      */
-               csum  = udplite_csum_outgoing(sk, skb);
+               csum = udplite_csum(skb);
 
        else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */
 
@@ -740,20 +737,20 @@ static int udp_push_pending_frames(struct sock *sk)
 
        } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 
-               udp4_hwcsum_outgoing(sk, skb, fl->fl4_src, fl->fl4_dst, up->len);
+               udp4_hwcsum(skb, rt->rt_src, daddr);
                goto send;
 
-       } else                                           /*   `normal' UDP    */
-               csum = udp_csum_outgoing(sk, skb);
+       } else
+               csum = udp_csum(skb);
 
        /* add protocol-dependent pseudo-header */
-       uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst, up->len,
+       uh->check = csum_tcpudp_magic(rt->rt_src, daddr, len,
                                      sk->sk_protocol, csum);
        if (uh->check == 0)
                uh->check = CSUM_MANGLED_0;
 
 send:
-       err = ip_push_pending_frames(sk);
+       err = ip_send_skb(skb);
        if (err) {
                if (err == -ENOBUFS && !inet->recverr) {
                        UDP_INC_STATS_USER(sock_net(sk),
@@ -763,6 +760,26 @@ send:
        } else
                UDP_INC_STATS_USER(sock_net(sk),
                                   UDP_MIB_OUTDATAGRAMS, is_udplite);
+       return err;
+}
+
+/*
+ * Push out all pending data as one UDP datagram. Socket is locked.
+ */
+static int udp_push_pending_frames(struct sock *sk)
+{
+       struct udp_sock  *up = udp_sk(sk);
+       struct inet_sock *inet = inet_sk(sk);
+       struct flowi *fl = &inet->cork.fl;
+       struct sk_buff *skb;
+       int err = 0;
+
+       skb = ip_finish_skb(sk);
+       if (!skb)
+               goto out;
+
+       err = udp_send_skb(skb, fl->fl4_dst, fl->fl_ip_dport);
+
 out:
        up->len = 0;
        up->pending = 0;