From 2e8de8576343ab540856082916bfb84d17288b08 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Thu, 26 Apr 2018 13:42:20 -0400 Subject: udp: add gso segment cmsg Allow specifying segment size in the send call. The new control message performs the same function as socket option UDP_SEGMENT while avoiding the extra system call. [ Export udp_cmsg_send for ipv6. -DaveM ] Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/ipv4/udp.c | 44 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 42 insertions(+), 2 deletions(-) (limited to 'net/ipv4/udp.c') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index bda022c5480b..794aeafeb782 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -853,6 +853,43 @@ out: } EXPORT_SYMBOL(udp_push_pending_frames); +static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size) +{ + switch (cmsg->cmsg_type) { + case UDP_SEGMENT: + if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16))) + return -EINVAL; + *gso_size = *(__u16 *)CMSG_DATA(cmsg); + return 0; + default: + return -EINVAL; + } +} + +int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size) +{ + struct cmsghdr *cmsg; + bool need_ip = false; + int err; + + for_each_cmsghdr(cmsg, msg) { + if (!CMSG_OK(msg, cmsg)) + return -EINVAL; + + if (cmsg->cmsg_level != SOL_UDP) { + need_ip = true; + continue; + } + + err = __udp_cmsg_send(cmsg, gso_size); + if (err) + return err; + } + + return need_ip; +} +EXPORT_SYMBOL_GPL(udp_cmsg_send); + int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) { struct inet_sock *inet = inet_sk(sk); @@ -941,8 +978,11 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) ipc.gso_size = up->gso_size; if (msg->msg_controllen) { - err = ip_cmsg_send(sk, msg, &ipc, sk->sk_family == AF_INET6); - if (unlikely(err)) { + err = udp_cmsg_send(sk, msg, &ipc.gso_size); + if (err > 0) + err = ip_cmsg_send(sk, msg, &ipc, + sk->sk_family == AF_INET6); + if (unlikely(err < 0)) { kfree(ipc.opt); return err; } -- cgit v1.2.3-59-g8ed1b