netdev - [RFC 04/14] tcp_smc: Make smc_parse

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Message-id: <20171218215109.38700-5-cpaasch@apple.com>
Date:   Mon, 18 Dec 2017 13:50:59 -0800
From:   Christoph Paasch <cpaasch@...le.com>
To:     netdev@...r.kernel.org
Cc:     Eric Dumazet <edumazet@...gle.com>,
        Mat Martineau <mathew.j.martineau@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Ursula Braun <ubraun@...ux.vnet.ibm.com>
Subject: [RFC 04/14] tcp_smc: Make smc_parse_options return 1 on success

As we allow a generic TCP-option parser that also parses experimental
TCP options, we need to add a return-value to smc_parse_options() that
indicates whether the option actually matched or not.

Cc: Ursula Braun <ubraun@...ux.vnet.ibm.com>
Signed-off-by: Christoph Paasch <cpaasch@...le.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
 net/ipv4/tcp_input.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index eb97ee24c601..5c35fd568b13 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3671,19 +3671,22 @@ static void tcp_parse_fastopen_option(int len, const unsigned char *cookie,
 	foc->exp = exp_opt;
 }
 
-static void smc_parse_options(const struct tcphdr *th,
-			      struct tcp_options_received *opt_rx,
-			      const unsigned char *ptr,
-			      int opsize)
+static int smc_parse_options(const struct tcphdr *th,
+			     struct tcp_options_received *opt_rx,
+			     const unsigned char *ptr,
+			     int opsize)
 {
 #if IS_ENABLED(CONFIG_SMC)
 	if (static_branch_unlikely(&tcp_have_smc)) {
 		if (th->syn && !(opsize & 1) &&
 		    opsize >= TCPOLEN_EXP_SMC_BASE &&
-		    get_unaligned_be32(ptr) == TCPOPT_SMC_MAGIC)
+		    get_unaligned_be32(ptr) == TCPOPT_SMC_MAGIC) {
 			opt_rx->smc_ok = 1;
+			return 1;
+		}
 	}
 #endif
+	return 0;
 }
 
 /* Look for tcp options. Normally only called on SYN and SYNACK packets.
-- 
2.15.0