From: Gilad Ben-Yossef <gilad@codefidence.com>
Date: Wed, 28 Oct 2009 04:15:24 +0000 (+0000)
Subject: Add the no SACK route option feature
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1aba721eba1d84a2defce45b950272cee1e6c72a;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

Add the no SACK route option feature

Implement querying and acting upon the no sack bit in the features
field.

Signed-off-by: Gilad Ben-Yossef <gilad@codefidence.com>
Sigend-off-by: Ori Finkelman <ori@comsleep.com>
Sigend-off-by: Yony Amit <yony@comsleep.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index adf2068d12b5..9c802a6b04d3 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -377,7 +377,7 @@ enum
 #define RTAX_MAX (__RTAX_MAX - 1)
 
 #define RTAX_FEATURE_ECN	0x00000001
-#define RTAX_FEATURE_SACK	0x00000002
+#define RTAX_FEATURE_NO_SACK	0x00000002
 #define RTAX_FEATURE_TIMESTAMP	0x00000004
 #define RTAX_FEATURE_ALLFRAG	0x00000008
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c7625005486d..5fb25f977451 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3763,7 +3763,8 @@ void tcp_parse_options(struct sk_buff *skb, struct tcp_options_received *opt_rx,
 				break;
 			case TCPOPT_SACK_PERM:
 				if (opsize == TCPOLEN_SACK_PERM && th->syn &&
-				    !estab && sysctl_tcp_sack) {
+				    !estab && sysctl_tcp_sack &&
+				    !dst_feature(dst, RTAX_FEATURE_NO_SACK)) {
 					opt_rx->sack_ok = 1;
 					tcp_sack_reset(opt_rx);
 				}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 2e2eb74ac4cc..b35802af3c4c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -464,6 +464,7 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 				struct tcp_md5sig_key **md5) {
 	struct tcp_sock *tp = tcp_sk(sk);
 	unsigned size = 0;
+	struct dst_entry *dst = __sk_dst_get(sk);
 
 #ifdef CONFIG_TCP_MD5SIG
 	*md5 = tp->af_specific->md5_lookup(sk, sk);
@@ -498,7 +499,8 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 		opts->options |= OPTION_WSCALE;
 		size += TCPOLEN_WSCALE_ALIGNED;
 	}
-	if (likely(sysctl_tcp_sack)) {
+	if (likely(sysctl_tcp_sack &&
+		   !dst_feature(dst, RTAX_FEATURE_NO_SACK))) {
 		opts->options |= OPTION_SACK_ADVERTISE;
 		if (unlikely(!(OPTION_TS & opts->options)))
 			size += TCPOLEN_SACKPERM_ALIGNED;