udp: Remove partial csum code in TX.

UDP TX paths also have some code for UDP-Lite partial
checksum:

  * udplite_csum() in udp_send_skb() and udp_v6_send_skb()
  * udplite_getfrag() in udp_sendmsg() and udpv6_sendmsg()

Let's remove such code.

Now, we can use IPPROTO_UDP directly instead of sk->sk_protocol
or fl6->flowi6_proto for csum_tcpudp_magic() and csum_ipv6_magic().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260311052020.1213705-9-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/udplite.h b/include/net/udplite.h
index 0456a14c993b65e881b9db321d2b226d31c5c6ca..6bfa1d6833d125d17afc268ed92f6ad7872cd48d 100644 (file)
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -12,39 +12,4 @@
 #define UDPLITE_SEND_CSCOV   10 /* sender partial coverage (as sent)      */
 #define UDPLITE_RECV_CSCOV   11 /* receiver partial coverage (threshold ) */
 
-/*
- *     Checksum computation is all in software, hence simpler getfrag.
- */
-static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
-                                     int len, int odd, struct sk_buff *skb)
-{
-       struct msghdr *msg = from;
-       return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
-}
-
-/*
- *     Checksumming routines
- */
-
-/* Fast-path computation of checksum. Socket may not be locked. */
-static inline __wsum udplite_csum(struct sk_buff *skb)
-{
-       const int off = skb_transport_offset(skb);
-       const struct sock *sk = skb->sk;
-       int len = skb->len - off;
-
-       if (udp_test_bit(UDPLITE_SEND_CC, sk)) {
-               u16 pcslen = READ_ONCE(udp_sk(sk)->pcslen);
-
-               if (pcslen < len) {
-                       if (pcslen > 0)
-                               len = pcslen;
-                       udp_hdr(skb)->len = htons(pcslen);
-               }
-       }
-       skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
-
-       return skb_checksum(skb, off, len, 0);
-}
-
 #endif /* _UDPLITE_H */

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d42fb9330c22ecd4991a12d059769331e5e4869e..9a2c8ff96e837fe2cd2688cbd6443b2c3360c1d3 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1120,20 +1120,19 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
                        struct inet_cork *cork)
 {
        struct sock *sk = skb->sk;
-       struct inet_sock *inet = inet_sk(sk);
+       int offset, len, datalen;
        struct udphdr *uh;
        int err;
-       int is_udplite = IS_UDPLITE(sk);
-       int offset = skb_transport_offset(skb);
-       int len = skb->len - offset;
-       int datalen = len - sizeof(*uh);
-       __wsum csum = 0;
+
+       offset = skb_transport_offset(skb);
+       len = skb->len - offset;
+       datalen = len - sizeof(*uh);
 
        /*
         * Create a UDP header
         */
        uh = udp_hdr(skb);
-       uh->source = inet->inet_sport;
+       uh->source = inet_sk(sk)->inet_sport;
        uh->dest = fl4->fl4_dport;
        uh->len = htons(len);
        uh->check = 0;
@@ -1154,7 +1153,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
                        kfree_skb(skb);
                        return -EINVAL;
                }
-               if (is_udplite || dst_xfrm(skb_dst(skb))) {
+               if (dst_xfrm(skb_dst(skb))) {
                        kfree_skb(skb);
                        return -EIO;
                }
@@ -1170,26 +1169,18 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
                }
        }
 
-       if (is_udplite)                                  /*     UDP-Lite      */
-               csum = udplite_csum(skb);
-
-       else if (sk->sk_no_check_tx) {                   /* UDP csum off */
-
+       if (sk->sk_no_check_tx) {                        /* UDP csum off */
                skb->ip_summed = CHECKSUM_NONE;
                goto send;
-
        } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 csum_partial:
-
                udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
                goto send;
-
-       } else
-               csum = udp_csum(skb);
+       }
 
        /* add protocol-dependent pseudo-header */
        uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
-                                     sk->sk_protocol, csum);
+                                     IPPROTO_UDP, udp_csum(skb));
        if (uh->check == 0)
                uh->check = CSUM_MANGLED_0;
 
@@ -1270,26 +1261,23 @@ EXPORT_IPV6_MOD_GPL(udp_cmsg_send);
 
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
+       int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
        DEFINE_RAW_FLEX(struct ip_options_rcu, opt_copy, opt.__data,
                        IP_OPTIONS_DATA_FIXED_SIZE);
+       DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
+       int ulen = len, free = 0, connected = 0;
        struct inet_sock *inet = inet_sk(sk);
        struct udp_sock *up = udp_sk(sk);
-       DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
+       __be32 daddr, faddr, saddr;
+       struct rtable *rt = NULL;
        struct flowi4 fl4_stack;
-       struct flowi4 *fl4;
-       int ulen = len;
        struct ipcm_cookie ipc;
-       struct rtable *rt = NULL;
-       int free = 0;
-       int connected = 0;
-       __be32 daddr, faddr, saddr;
-       u8 scope;
-       __be16 dport;
-       int err, is_udplite = IS_UDPLITE(sk);
-       int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
-       int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
        struct sk_buff *skb;
+       struct flowi4 *fl4;
+       __be16 dport;
        int uc_index;
+       u8 scope;
+       int err;
 
        if (len > 0xFFFF)
                return -EMSGSIZE;
@@ -1301,8 +1289,6 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
        if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
                return -EOPNOTSUPP;
 
-       getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
-
        fl4 = &inet->cork.fl.u.ip4;
        if (READ_ONCE(up->pending)) {
                /*
@@ -1444,7 +1430,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
                flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark,
                                   ipc.tos & INET_DSCP_MASK, scope,
-                                  sk->sk_protocol, flow_flags, faddr, saddr,
+                                  IPPROTO_UDP, flow_flags, faddr, saddr,
                                   dport, inet->inet_sport,
                                   sk_uid(sk));
 
@@ -1478,7 +1464,7 @@ back_from_confirm:
        if (!corkreq) {
                struct inet_cork cork;
 
-               skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
+               skb = ip_make_skb(sk, fl4, ip_generic_getfrag, msg, ulen,
                                  sizeof(struct udphdr), &ipc, &rt,
                                  &cork, msg->msg_flags);
                err = PTR_ERR(skb);
@@ -1509,7 +1495,7 @@ back_from_confirm:
 
 do_append_data:
        up->len += ulen;
-       err = ip_append_data(sk, fl4, getfrag, msg, ulen,
+       err = ip_append_data(sk, fl4, ip_generic_getfrag, msg, ulen,
                             sizeof(struct udphdr), &ipc, &rt,
                             corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
        if (err)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index bf5430ea66f0a821089b69eb432694f65e0e9447..511e3f898be507e1c064c9af1ff5425ce39eeae6 100644 (file)
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1370,13 +1370,13 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
                           struct inet_cork *cork)
 {
        struct sock *sk = skb->sk;
+       int offset, len, datalen;
        struct udphdr *uh;
        int err = 0;
-       int is_udplite = IS_UDPLITE(sk);
-       __wsum csum = 0;
-       int offset = skb_transport_offset(skb);
-       int len = skb->len - offset;
-       int datalen = len - sizeof(*uh);
+
+       offset = skb_transport_offset(skb);
+       len = skb->len - offset;
+       datalen = len - sizeof(*uh);
 
        /*
         * Create a UDP header
@@ -1403,7 +1403,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
                        kfree_skb(skb);
                        return -EINVAL;
                }
-               if (is_udplite || dst_xfrm(skb_dst(skb))) {
+               if (dst_xfrm(skb_dst(skb))) {
                        kfree_skb(skb);
                        return -EIO;
                }
@@ -1419,21 +1419,18 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
                }
        }
 
-       if (is_udplite)
-               csum = udplite_csum(skb);
-       else if (udp_get_no_check6_tx(sk)) {   /* UDP csum disabled */
+       if (udp_get_no_check6_tx(sk)) {   /* UDP csum disabled */
                skb->ip_summed = CHECKSUM_NONE;
                goto send;
        } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 csum_partial:
                udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
                goto send;
-       } else
-               csum = udp_csum(skb);
+       }
 
        /* add protocol-dependent pseudo-header */
        uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
-                                   len, fl6->flowi6_proto, csum);
+                                   len, IPPROTO_UDP, udp_csum(skb));
        if (uh->check == 0)
                uh->check = CSUM_MANGLED_0;
 
@@ -1473,27 +1470,26 @@ out:
 
 int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
-       struct ipv6_txoptions opt_space;
-       struct udp_sock *up = udp_sk(sk);
-       struct inet_sock *inet = inet_sk(sk);
-       struct ipv6_pinfo *np = inet6_sk(sk);
+       int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
        DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
-       struct in6_addr *daddr, *final_p, final;
-       struct ipv6_txoptions *opt = NULL;
        struct ipv6_txoptions *opt_to_free = NULL;
+       struct in6_addr *daddr, *final_p, final;
        struct ip6_flowlabel *flowlabel = NULL;
+       struct inet_sock *inet = inet_sk(sk);
+       struct ipv6_pinfo *np = inet6_sk(sk);
+       struct ipv6_txoptions *opt = NULL;
+       struct udp_sock *up = udp_sk(sk);
+       struct ipv6_txoptions opt_space;
+       int addr_len = msg->msg_namelen;
        struct inet_cork_full cork;
-       struct flowi6 *fl6 = &cork.fl.u.ip6;
-       struct dst_entry *dst;
        struct ipcm6_cookie ipc6;
-       int addr_len = msg->msg_namelen;
        bool connected = false;
+       struct dst_entry *dst;
+       struct flowi6 *fl6;
        int ulen = len;
-       int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
        int err;
-       int is_udplite = IS_UDPLITE(sk);
-       int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 
+       fl6 = &cork.fl.u.ip6;
        ipcm6_init_sk(&ipc6, sk);
        ipc6.gso_size = READ_ONCE(up->gso_size);
 
@@ -1552,7 +1548,6 @@ do_udp_sendmsg:
        if (len > INT_MAX - sizeof(struct udphdr))
                return -EMSGSIZE;
 
-       getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
        if (READ_ONCE(up->pending)) {
                if (READ_ONCE(up->pending) == AF_INET)
                        return udp_sendmsg(sk, msg, len);
@@ -1654,7 +1649,7 @@ do_udp_sendmsg:
        opt = ipv6_fixup_options(&opt_space, opt);
        ipc6.opt = opt;
 
-       fl6->flowi6_proto = sk->sk_protocol;
+       fl6->flowi6_proto = IPPROTO_UDP;
        fl6->flowi6_mark = ipc6.sockc.mark;
        fl6->daddr = *daddr;
        if (ipv6_addr_any(&fl6->saddr) && !ipv6_addr_any(&np->saddr))
@@ -1721,7 +1716,7 @@ back_from_confirm:
        if (!corkreq) {
                struct sk_buff *skb;
 
-               skb = ip6_make_skb(sk, getfrag, msg, ulen,
+               skb = ip6_make_skb(sk, ip_generic_getfrag, msg, ulen,
                                   sizeof(struct udphdr), &ipc6,
                                   dst_rt6_info(dst),
                                   msg->msg_flags, &cork);
@@ -1747,8 +1742,9 @@ back_from_confirm:
 
 do_append_data:
        up->len += ulen;
-       err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr),
-                             &ipc6, fl6, dst_rt6_info(dst),
+       err = ip6_append_data(sk, ip_generic_getfrag, msg, ulen,
+                             sizeof(struct udphdr), &ipc6, fl6,
+                             dst_rt6_info(dst),
                              corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
        if (err)
                udp_v6_flush_pending_frames(sk);