From 759e5d006462d53fb708daa8284b4ad909415da1 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 25 Mar 2007 20:10:56 -0700 Subject: [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 Signed-off-by: David S. Miller --- net/ipv6/udp.c | 74 +++++++++++++++++++++++++++++++----------------------- net/ipv6/udplite.c | 2 +- 2 files changed, 43 insertions(+), 33 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3413fc22ce4a..733371689795 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -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); } /* diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c index 629f97162fbc..f54016a55004 100644 --- a/net/ipv6/udplite.c +++ b/net/ipv6/udplite.c @@ -19,7 +19,7 @@ DEFINE_SNMP_STAT(struct udp_mib, udplite_stats_in6) __read_mostly; static int udplitev6_rcv(struct sk_buff **pskb) { - return __udp6_lib_rcv(pskb, udplite_hash, 1); + return __udp6_lib_rcv(pskb, udplite_hash, IPPROTO_UDPLITE); } static void udplitev6_err(struct sk_buff *skb, -- cgit v1.2.3-59-g8ed1b