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/ipv4/udp.c | 96 ++++++++++++++++++++++++++++-------------------------- net/ipv4/udplite.c | 2 +- 2 files changed, 50 insertions(+), 48 deletions(-) (limited to 'net/ipv4') 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); diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c index b28fe1edf98..f34fd686a8f 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) -- cgit v1.2.3