[UDP]: Clean up UDP-Lite receive checksum
This patch eliminates some duplicate code for the verification of
receive checksums between UDP-Lite and UDP. It does this by
introducing __skb_checksum_complete_head which is identical to
__skb_checksum_complete_head apart from the fact that it takes
a length parameter rather than computing the first skb->len bytes.
As a result UDP-Lite will be able to use hardware checksum offload
for packets which do not use partial coverage checksums. It also
means that UDP-Lite loopback no longer does unnecessary checksum
verification.
If any NICs start support UDP-Lite this would also start working
automatically.
This patch removes the assumption that msg_flags has MSG_TRUNC clear
upon entry in recvmsg.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 3413fc2..7333716 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -120,8 +120,9 @@
struct ipv6_pinfo *np = inet6_sk(sk);
struct inet_sock *inet = inet_sk(sk);
struct sk_buff *skb;
- size_t copied;
- int err, copy_only, is_udplite = IS_UDPLITE(sk);
+ unsigned int ulen, copied;
+ int err;
+ int is_udplite = IS_UDPLITE(sk);
if (addr_len)
*addr_len=sizeof(struct sockaddr_in6);
@@ -134,24 +135,25 @@
if (!skb)
goto out;
- copied = skb->len - sizeof(struct udphdr);
- if (copied > len) {
- copied = len;
+ ulen = skb->len - sizeof(struct udphdr);
+ copied = len;
+ if (copied > ulen)
+ copied = ulen;
+ else if (copied < ulen)
msg->msg_flags |= MSG_TRUNC;
- }
/*
- * Decide whether to checksum and/or copy data.
+ * If checksum is needed at all, try to do it while copying the
+ * data. If the data is truncated, or if we only want a partial
+ * coverage checksum (UDP-Lite), do it before the copy.
*/
- copy_only = (skb->ip_summed==CHECKSUM_UNNECESSARY);
- if (is_udplite || (!copy_only && msg->msg_flags&MSG_TRUNC)) {
- if (__udp_lib_checksum_complete(skb))
+ if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
+ if (udp_lib_checksum_complete(skb))
goto csum_copy_err;
- copy_only = 1;
}
- if (copy_only)
+ if (skb->ip_summed == CHECKSUM_UNNECESSARY)
err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
msg->msg_iov, copied );
else {
@@ -194,7 +196,7 @@
err = copied;
if (flags & MSG_TRUNC)
- err = skb->len - sizeof(struct udphdr);
+ err = ulen;
out_free:
skb_free_datagram(sk, skb);
@@ -368,9 +370,20 @@
return 0;
}
-static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh)
-
+static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh,
+ int proto)
{
+ int err;
+
+ UDP_SKB_CB(skb)->partial_cov = 0;
+ UDP_SKB_CB(skb)->cscov = skb->len;
+
+ if (proto == IPPROTO_UDPLITE) {
+ err = udplite_checksum_init(skb, uh);
+ if (err)
+ return err;
+ }
+
if (uh->check == 0) {
/* RFC 2460 section 8.1 says that we SHOULD log
this error. Well, it is reasonable.
@@ -380,20 +393,19 @@
}
if (skb->ip_summed == CHECKSUM_COMPLETE &&
!csum_ipv6_magic(&skb->nh.ipv6h->saddr, &skb->nh.ipv6h->daddr,
- skb->len, IPPROTO_UDP, skb->csum ))
+ skb->len, proto, skb->csum))
skb->ip_summed = CHECKSUM_UNNECESSARY;
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->csum = ~csum_unfold(csum_ipv6_magic(&skb->nh.ipv6h->saddr,
&skb->nh.ipv6h->daddr,
- skb->len, IPPROTO_UDP,
- 0));
+ skb->len, proto, 0));
- return (UDP_SKB_CB(skb)->partial_cov = 0);
+ return 0;
}
int __udp6_lib_rcv(struct sk_buff **pskb, struct hlist_head udptable[],
- int is_udplite)
+ int proto)
{
struct sk_buff *skb = *pskb;
struct sock *sk;
@@ -413,7 +425,8 @@
if (ulen > skb->len)
goto short_packet;
- if(! is_udplite ) { /* UDP validates ulen. */
+ if (proto == IPPROTO_UDP) {
+ /* UDP validates ulen. */
/* Check for jumbo payload */
if (ulen == 0)
@@ -429,15 +442,11 @@
daddr = &skb->nh.ipv6h->daddr;
uh = skb->h.uh;
}
-
- if (udp6_csum_init(skb, uh))
- goto discard;
-
- } else { /* UDP-Lite validates cscov. */
- if (udplite6_csum_init(skb, uh))
- goto discard;
}
+ if (udp6_csum_init(skb, uh, proto))
+ goto discard;
+
/*
* Multicast receive code
*/
@@ -459,7 +468,7 @@
if (udp_lib_checksum_complete(skb))
goto discard;
- UDP6_INC_STATS_BH(UDP_MIB_NOPORTS, is_udplite);
+ UDP6_INC_STATS_BH(UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0, dev);
@@ -475,17 +484,18 @@
short_packet:
LIMIT_NETDEBUG(KERN_DEBUG "UDP%sv6: short packet: %d/%u\n",
- is_udplite? "-Lite" : "", ulen, skb->len);
+ proto == IPPROTO_UDPLITE ? "-Lite" : "",
+ ulen, skb->len);
discard:
- UDP6_INC_STATS_BH(UDP_MIB_INERRORS, is_udplite);
+ UDP6_INC_STATS_BH(UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return(0);
}
static __inline__ int udpv6_rcv(struct sk_buff **pskb)
{
- return __udp6_lib_rcv(pskb, udp_hash, 0);
+ return __udp6_lib_rcv(pskb, udp_hash, IPPROTO_UDP);
}
/*