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authorHerbert Xu <herbert@gondor.apana.org.au>2007-03-25 20:10:56 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:23:51 -0700
commit759e5d006462d53fb708daa8284b4ad909415da1 (patch)
treeedcc4e9d975199b3fe5e2aadc3d1e06824755e75 /net/ipv4/udp.c
parent1ab6eb62b02e0949a392fb19bf31ba59ae1022b1 (diff)
[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>
Diffstat (limited to 'net/ipv4/udp.c')
-rw-r--r--net/ipv4/udp.c96
1 files changed, 49 insertions, 47 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index fc620a7c1db..86368832d48 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -810,7 +810,9 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
struct inet_sock *inet = inet_sk(sk);
struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
struct sk_buff *skb;
- int copied, err, copy_only, is_udplite = IS_UDPLITE(sk);
+ unsigned int ulen, copied;
+ int err;
+ int is_udplite = IS_UDPLITE(sk);
/*
* Check any passed addresses
@@ -826,28 +828,25 @@ 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.
- *
- * UDP: checksum may have been computed in HW,
- * (re-)compute it if message is truncated.
- * UDP-Lite: always needs to checksum, no HW support.
+ * 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 {
@@ -875,7 +874,7 @@ try_again:
err = copied;
if (flags & MSG_TRUNC)
- err = skb->len - sizeof(struct udphdr);
+ err = ulen;
out_free:
skb_free_datagram(sk, skb);
@@ -1095,10 +1094,9 @@ int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
}
}
- if (sk->sk_filter && skb->ip_summed != CHECKSUM_UNNECESSARY) {
- if (__udp_lib_checksum_complete(skb))
+ if (sk->sk_filter) {
+ if (udp_lib_checksum_complete(skb))
goto drop;
- skb->ip_summed = CHECKSUM_UNNECESSARY;
}
if ((rc = sock_queue_rcv_skb(sk,skb)) < 0) {
@@ -1166,25 +1164,36 @@ static int __udp4_lib_mcast_deliver(struct sk_buff *skb,
* Otherwise, csum completion requires chacksumming packet body,
* including udp header and folding it to skb->csum.
*/
-static inline void udp4_csum_init(struct sk_buff *skb, struct udphdr *uh)
+static inline int udp4_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) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
if (!csum_tcpudp_magic(skb->nh.iph->saddr, skb->nh.iph->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_tcpudp_nofold(skb->nh.iph->saddr,
skb->nh.iph->daddr,
- skb->len, IPPROTO_UDP, 0);
+ skb->len, proto, 0);
/* Probably, we should checksum udp header (it should be in cache
* in any case) and data in tiny packets (< rx copybreak).
*/
- /* UDP = UDP-Lite with a non-partial checksum coverage */
- UDP_SKB_CB(skb)->partial_cov = 0;
+ return 0;
}
/*
@@ -1192,7 +1201,7 @@ static inline void udp4_csum_init(struct sk_buff *skb, struct udphdr *uh)
*/
int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
- int is_udplite)
+ int proto)
{
struct sock *sk;
struct udphdr *uh = skb->h.uh;
@@ -1211,19 +1220,16 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
if (ulen > skb->len)
goto short_packet;
- if(! is_udplite ) { /* UDP validates ulen. */
-
+ if (proto == IPPROTO_UDP) {
+ /* UDP validates ulen. */
if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
goto short_packet;
uh = skb->h.uh;
-
- udp4_csum_init(skb, uh);
-
- } else { /* UDP-Lite validates cscov. */
- if (udplite4_csum_init(skb, uh))
- goto csum_error;
}
+ if (udp4_csum_init(skb, uh, proto))
+ goto csum_error;
+
if(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
return __udp4_lib_mcast_deliver(skb, uh, saddr, daddr, udptable);
@@ -1250,7 +1256,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
if (udp_lib_checksum_complete(skb))
goto csum_error;
- UDP_INC_STATS_BH(UDP_MIB_NOPORTS, is_udplite);
+ UDP_INC_STATS_BH(UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
/*
@@ -1262,7 +1268,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
short_packet:
LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %u.%u.%u.%u:%u %d/%d to %u.%u.%u.%u:%u\n",
- is_udplite? "-Lite" : "",
+ proto == IPPROTO_UDPLITE ? "-Lite" : "",
NIPQUAD(saddr),
ntohs(uh->source),
ulen,
@@ -1277,21 +1283,21 @@ csum_error:
* the network is concerned, anyway) as per 4.1.3.4 (MUST).
*/
LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %d.%d.%d.%d:%d to %d.%d.%d.%d:%d ulen %d\n",
- is_udplite? "-Lite" : "",
+ proto == IPPROTO_UDPLITE ? "-Lite" : "",
NIPQUAD(saddr),
ntohs(uh->source),
NIPQUAD(daddr),
ntohs(uh->dest),
ulen);
drop:
- UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_udplite);
+ UDP_INC_STATS_BH(UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return(0);
}
__inline__ int udp_rcv(struct sk_buff *skb)
{
- return __udp4_lib_rcv(skb, udp_hash, 0);
+ return __udp4_lib_rcv(skb, udp_hash, IPPROTO_UDP);
}
int udp_destroy_sock(struct sock *sk)
@@ -1486,15 +1492,11 @@ unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
struct sk_buff *skb;
spin_lock_bh(&rcvq->lock);
- while ((skb = skb_peek(rcvq)) != NULL) {
- if (udp_lib_checksum_complete(skb)) {
- UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_lite);
- __skb_unlink(skb, rcvq);
- kfree_skb(skb);
- } else {
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- break;
- }
+ while ((skb = skb_peek(rcvq)) != NULL &&
+ udp_lib_checksum_complete(skb)) {
+ UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_lite);
+ __skb_unlink(skb, rcvq);
+ kfree_skb(skb);
}
spin_unlock_bh(&rcvq->lock);