From ee9dfbef02d186a90f3a4876b276701966a92d10 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Thu, 26 Apr 2018 17:18:21 +0200 Subject: [PATCH] net/smc: handle sockopts forcing fallback Several TCP sockopts do not work for SMC. One example are the TCP_FASTOPEN sockopts, since SMC-connection setup is based on the TCP three-way-handshake. If the SMC socket is still in state SMC_INIT, such sockopts trigger fallback to TCP. Otherwise an error is returned. Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/smc/af_smc.c | 54 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 50 insertions(+), 4 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 4470501374bf..d274be7265ea 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -391,6 +391,9 @@ static int smc_connect_rdma(struct smc_sock *smc) sock_hold(&smc->sk); /* sock put in passive closing */ + if (smc->use_fallback) + goto out_connected; + if (!tcp_sk(smc->clcsock->sk)->syn_smc) { /* peer has not signalled SMC-capability */ smc->use_fallback = true; @@ -790,6 +793,9 @@ static void smc_listen_work(struct work_struct *work) int rc = 0; u8 ibport; + if (new_smc->use_fallback) + goto out_connected; + /* check if peer is smc capable */ if (!tcp_sk(newclcsock->sk)->syn_smc) { new_smc->use_fallback = true; @@ -968,7 +974,7 @@ static void smc_tcp_listen_work(struct work_struct *work) continue; new_smc->listen_smc = lsmc; - new_smc->use_fallback = false; /* assume rdma capability first*/ + new_smc->use_fallback = lsmc->use_fallback; sock_hold(lsk); /* sock_put in smc_listen_work */ INIT_WORK(&new_smc->smc_listen_work, smc_listen_work); smc_copy_sock_settings_to_smc(new_smc); @@ -1004,7 +1010,8 @@ static int smc_listen(struct socket *sock, int backlog) * them to the clc socket -- copy smc socket options to clc socket */ smc_copy_sock_settings_to_clc(smc); - tcp_sk(smc->clcsock->sk)->syn_smc = 1; + if (!smc->use_fallback) + tcp_sk(smc->clcsock->sk)->syn_smc = 1; rc = kernel_listen(smc->clcsock, backlog); if (rc) @@ -1097,6 +1104,16 @@ static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) (sk->sk_state != SMC_APPCLOSEWAIT1) && (sk->sk_state != SMC_INIT)) goto out; + + if (msg->msg_flags & MSG_FASTOPEN) { + if (sk->sk_state == SMC_INIT) { + smc->use_fallback = true; + } else { + rc = -EINVAL; + goto out; + } + } + if (smc->use_fallback) rc = smc->clcsock->ops->sendmsg(smc->clcsock, msg, len); else @@ -1274,14 +1291,43 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, { struct sock *sk = sock->sk; struct smc_sock *smc; + int rc; smc = smc_sk(sk); /* generic setsockopts reaching us here always apply to the * CLC socket */ - return smc->clcsock->ops->setsockopt(smc->clcsock, level, optname, - optval, optlen); + rc = smc->clcsock->ops->setsockopt(smc->clcsock, level, optname, + optval, optlen); + if (smc->clcsock->sk->sk_err) { + sk->sk_err = smc->clcsock->sk->sk_err; + sk->sk_error_report(sk); + } + if (rc) + return rc; + + lock_sock(sk); + switch (optname) { + case TCP_ULP: + case TCP_FASTOPEN: + case TCP_FASTOPEN_CONNECT: + case TCP_FASTOPEN_KEY: + case TCP_FASTOPEN_NO_COOKIE: + /* option not supported by SMC */ + if (sk->sk_state == SMC_INIT) { + smc->use_fallback = true; + } else { + if (!smc->use_fallback) + rc = -EINVAL; + } + break; + default: + break; + } + release_sock(sk); + + return rc; } static int smc_getsockopt(struct socket *sock, int level, int optname,