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authorUrsula Braun <ubraun@linux.vnet.ibm.com>2017-10-25 12:01:45 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-26 12:00:29 +0300
commit60e2a7780793bae0debc275a9ccd57f7da0cf195 (patch)
tree8b65c6c4eb3194718df692952e1b5d547c53de2f /net/ipv4/tcp_minisocks.c
parent145686baab68e9c7594fe9269f47da479c25ad79 (diff)
downloadlinux-60e2a7780793bae0debc275a9ccd57f7da0cf195.tar.xz
tcp: TCP experimental option for SMC
The SMC protocol [1] relies on the use of a new TCP experimental option [2, 3]. With this option, SMC capabilities are exchanged between peers during the TCP three way handshake. This patch adds support for this experimental option to TCP. References: [1] SMC-R Informational RFC: http://www.rfc-editor.org/info/rfc7609 [2] Shared Use of TCP Experimental Options RFC 6994: https://tools.ietf.org/rfc/rfc6994.txt [3] IANA ExID SMCR: http://www.iana.org/assignments/tcp-parameters/tcp-parameters.xhtml#tcp-exids Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_minisocks.c')
-rw-r--r--net/ipv4/tcp_minisocks.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index a952357054f4..056009f1c14f 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -23,6 +23,7 @@
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/workqueue.h>
+#include <linux/static_key.h>
#include <net/tcp.h>
#include <net/inet_common.h>
#include <net/xfrm.h>
@@ -416,6 +417,21 @@ void tcp_ca_openreq_child(struct sock *sk, const struct dst_entry *dst)
}
EXPORT_SYMBOL_GPL(tcp_ca_openreq_child);
+static void smc_check_reset_syn_req(struct tcp_sock *oldtp,
+ struct request_sock *req,
+ struct tcp_sock *newtp)
+{
+#if IS_ENABLED(CONFIG_SMC)
+ struct inet_request_sock *ireq;
+
+ if (static_branch_unlikely(&tcp_have_smc)) {
+ ireq = inet_rsk(req);
+ if (oldtp->syn_smc && !ireq->smc_ok)
+ newtp->syn_smc = 0;
+ }
+#endif
+}
+
/* This is not only more efficient than what we used to do, it eliminates
* a lot of code duplication between IPv4/IPv6 SYN recv processing. -DaveM
*
@@ -433,6 +449,9 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
struct tcp_request_sock *treq = tcp_rsk(req);
struct inet_connection_sock *newicsk = inet_csk(newsk);
struct tcp_sock *newtp = tcp_sk(newsk);
+ struct tcp_sock *oldtp = tcp_sk(sk);
+
+ smc_check_reset_syn_req(oldtp, req, newtp);
/* Now setup tcp_sock */
newtp->pred_flags = 0;