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udplite: fast-path computation of checksum coverage
Commit 903ab86d19
of 1 March this year ("udp: Add
lockless transmit path") introduced a new fast TX path that broke the checksum
coverage computation of UDP-lite, which so far depended on up->len (only set
if the socket is locked and 0 in the fast path).
Fixed by providing both fast- and slow-path computation of checksum coverage.
The latter can be removed when UDP(-lite)v6 also uses a lockless transmit path.
Reported-by: Thomas Volkert <thomas@homer-conferencing.com>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
4c41042d1d
commit
f36c23bb9f
@ -66,41 +66,35 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
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return 0;
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}
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static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
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{
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int cscov = up->len;
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/*
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* Sender has set `partial coverage' option on UDP-Lite socket
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*/
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if (up->pcflag & UDPLITE_SEND_CC) {
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if (up->pcslen < up->len) {
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/* up->pcslen == 0 means that full coverage is required,
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* partial coverage only if 0 < up->pcslen < up->len */
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if (0 < up->pcslen) {
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cscov = up->pcslen;
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}
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uh->len = htons(up->pcslen);
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}
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/*
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* NOTE: Causes for the error case `up->pcslen > up->len':
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* (i) Application error (will not be penalized).
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* (ii) Payload too big for send buffer: data is split
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* into several packets, each with its own header.
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* In this case (e.g. last segment), coverage may
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* exceed packet length.
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* Since packets with coverage length > packet length are
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* illegal, we fall back to the defaults here.
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*/
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}
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return cscov;
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}
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/* Slow-path computation of checksum. Socket is locked. */
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static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
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{
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int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
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const struct udp_sock *up = udp_sk(skb->sk);
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int cscov = up->len;
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__wsum csum = 0;
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if (up->pcflag & UDPLITE_SEND_CC) {
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/*
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* Sender has set `partial coverage' option on UDP-Lite socket.
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* The special case "up->pcslen == 0" signifies full coverage.
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*/
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if (up->pcslen < up->len) {
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if (0 < up->pcslen)
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cscov = up->pcslen;
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udp_hdr(skb)->len = htons(up->pcslen);
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}
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/*
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* NOTE: Causes for the error case `up->pcslen > up->len':
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* (i) Application error (will not be penalized).
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* (ii) Payload too big for send buffer: data is split
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* into several packets, each with its own header.
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* In this case (e.g. last segment), coverage may
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* exceed packet length.
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* Since packets with coverage length > packet length are
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* illegal, we fall back to the defaults here.
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*/
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}
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skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
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skb_queue_walk(&sk->sk_write_queue, skb) {
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@ -115,16 +109,21 @@ static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
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return csum;
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}
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/* Fast-path computation of checksum. Socket may not be locked. */
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static inline __wsum udplite_csum(struct sk_buff *skb)
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{
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struct sock *sk = skb->sk;
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int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
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const struct udp_sock *up = udp_sk(skb->sk);
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const int off = skb_transport_offset(skb);
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const int len = skb->len - off;
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int len = skb->len - off;
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if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
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if (0 < up->pcslen)
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len = up->pcslen;
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udp_hdr(skb)->len = htons(up->pcslen);
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}
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skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
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return skb_checksum(skb, off, min(cscov, len), 0);
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return skb_checksum(skb, off, len, 0);
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}
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extern void udplite4_register(void);
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