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[UDP]: Clean up UDP-Lite receive checksum

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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>
This commit is contained in:
Herbert Xu
2007-03-25 20:10:56 -07:00
committed by David S. Miller
parent 1ab6eb62b0
commit 759e5d0064
8 changed files with 109 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
net/ipv6/udp.c
View File

@@ -120,8 +120,9 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
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 @@ try_again:
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 @@ try_again:
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 @@ out:
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 @@ static inline int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh)
}
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 @@ int __udp6_lib_rcv(struct sk_buff **pskb, struct hlist_head udptable[],
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 @@ int __udp6_lib_rcv(struct sk_buff **pskb, struct hlist_head udptable[],
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 @@ int __udp6_lib_rcv(struct sk_buff **pskb, struct hlist_head udptable[],
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 @@ int __udp6_lib_rcv(struct sk_buff **pskb, struct hlist_head udptable[],
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);
}
/*