From 759e5d006462d53fb708daa8284b4ad909415da1 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 25 Mar 2007 20:10:56 -0700 Subject: [PATCH] [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 --- include/linux/skbuff.h | 1 + include/net/udp.h | 5 +-- include/net/udplite.h | 39 +++-------------- net/core/datagram.c | 10 ++++- net/ipv4/udp.c | 96 +++++++++++++++++++++--------------------- net/ipv4/udplite.c | 2 +- net/ipv6/udp.c | 74 ++++++++++++++++++-------------- net/ipv6/udplite.c | 2 +- 8 files changed, 109 insertions(+), 120 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 30089adb2e..df229bd5f1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1372,6 +1372,7 @@ static inline void __net_timestamp(struct sk_buff *skb) } +extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len); extern __sum16 __skb_checksum_complete(struct sk_buff *skb); /** diff --git a/include/net/udp.h b/include/net/udp.h index 1b921fa814..4a9699f792 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -72,10 +72,7 @@ struct sk_buff; */ static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb) { - if (! UDP_SKB_CB(skb)->partial_cov) - return __skb_checksum_complete(skb); - return csum_fold(skb_checksum(skb, 0, UDP_SKB_CB(skb)->cscov, - skb->csum)); + return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov); } static inline int udp_lib_checksum_complete(struct sk_buff *skb) diff --git a/include/net/udplite.h b/include/net/udplite.h index 67ac514243..d99df75fe5 100644 --- a/include/net/udplite.h +++ b/include/net/udplite.h @@ -47,11 +47,10 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) return 1; } - UDP_SKB_CB(skb)->partial_cov = 0; cscov = ntohs(uh->len); if (cscov == 0) /* Indicates that full coverage is required. */ - cscov = skb->len; + ; else if (cscov < 8 || cscov > skb->len) { /* * Coverage length violates RFC 3828: log and discard silently. @@ -60,42 +59,16 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) cscov, skb->len); return 1; - } else if (cscov < skb->len) + } else if (cscov < skb->len) { UDP_SKB_CB(skb)->partial_cov = 1; - - UDP_SKB_CB(skb)->cscov = cscov; - - /* - * There is no known NIC manufacturer supporting UDP-Lite yet, - * hence ip_summed is always (re-)set to CHECKSUM_NONE. - */ - skb->ip_summed = CHECKSUM_NONE; + UDP_SKB_CB(skb)->cscov = cscov; + if (skb->ip_summed == CHECKSUM_COMPLETE) + skb->ip_summed = CHECKSUM_NONE; + } return 0; } -static __inline__ int udplite4_csum_init(struct sk_buff *skb, struct udphdr *uh) -{ - int rc = udplite_checksum_init(skb, uh); - - if (!rc) - skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr, - skb->nh.iph->daddr, - skb->len, IPPROTO_UDPLITE, 0); - return rc; -} - -static __inline__ int udplite6_csum_init(struct sk_buff *skb, struct udphdr *uh) -{ - int rc = udplite_checksum_init(skb, uh); - - if (!rc) - skb->csum = ~csum_unfold(csum_ipv6_magic(&skb->nh.ipv6h->saddr, - &skb->nh.ipv6h->daddr, - skb->len, IPPROTO_UDPLITE, 0)); - return rc; -} - static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh) { int cscov = up->len; diff --git a/net/core/datagram.c b/net/core/datagram.c index 186212b5b7..cb056f4761 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -411,11 +411,11 @@ fault: return -EFAULT; } -__sum16 __skb_checksum_complete(struct sk_buff *skb) +__sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len) { __sum16 sum; - sum = csum_fold(skb_checksum(skb, 0, skb->len, skb->csum)); + sum = csum_fold(skb_checksum(skb, 0, len, skb->csum)); if (likely(!sum)) { if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) netdev_rx_csum_fault(skb->dev); @@ -423,6 +423,12 @@ __sum16 __skb_checksum_complete(struct sk_buff *skb) } return sum; } +EXPORT_SYMBOL(__skb_checksum_complete_head); + +__sum16 __skb_checksum_complete(struct sk_buff *skb) +{ + return __skb_checksum_complete_head(skb, skb->len); +} EXPORT_SYMBOL(__skb_checksum_complete); /** diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index fc620a7c1d..86368832d4 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); diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c index b28fe1edf9..f34fd686a8 100644 --- a/net/ipv4/udplite.c +++ b/net/ipv4/udplite.c @@ -31,7 +31,7 @@ static int udplite_v4_get_port(struct sock *sk, unsigned short snum) static int udplite_rcv(struct sk_buff *skb) { - return __udp4_lib_rcv(skb, udplite_hash, 1); + return __udp4_lib_rcv(skb, udplite_hash, IPPROTO_UDPLITE); } static void udplite_err(struct sk_buff *skb, u32 info) diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 3413fc22ce..7333716897 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 629f97162f..f54016a550 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, -- 2.39.5