tcp: remove tcp_tw_recycle
The tcp_tw_recycle was already broken for connections
behind NAT, since the per-destination timestamp is not
monotonically increasing for multiple machines behind
a single destination address.
After the randomization of TCP timestamp offsets
in commit 8a5bd45f6616 (tcp: randomize tcp timestamp offsets
for each connection), the tcp_tw_recycle is broken for all
types of connections for the same reason: the timestamps
received from a single machine is not monotonically increasing,
anymore.
Remove tcp_tw_recycle, since it is not functional. Also, remove
the PAWSPassive SNMP counter since it is only used for
tcp_tw_recycle, and simplify tcp_v4_route_req and tcp_v6_route_req
since the strict argument is only set when tcp_tw_recycle is
enabled.
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Cc: Lutz Vieweg <lvml@5t9.de>
Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 69cf49e..4ccbf46 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -199,7 +199,6 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TW", LINUX_MIB_TIMEWAITED),
SNMP_MIB_ITEM("TWRecycled", LINUX_MIB_TIMEWAITRECYCLED),
SNMP_MIB_ITEM("TWKilled", LINUX_MIB_TIMEWAITKILLED),
- SNMP_MIB_ITEM("PAWSPassive", LINUX_MIB_PAWSPASSIVEREJECTED),
SNMP_MIB_ITEM("PAWSActive", LINUX_MIB_PAWSACTIVEREJECTED),
SNMP_MIB_ITEM("PAWSEstab", LINUX_MIB_PAWSESTABREJECTED),
SNMP_MIB_ITEM("DelayedACKs", LINUX_MIB_DELAYEDACKS),
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index d6880a6..11aaef0 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -981,13 +981,6 @@ static struct ctl_table ipv4_net_table[] = {
.proc_handler = proc_dointvec
},
{
- .procname = "tcp_tw_recycle",
- .data = &init_net.ipv4.tcp_death_row.sysctl_tw_recycle,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec
- },
- {
.procname = "tcp_max_syn_backlog",
.data = &init_net.ipv4.sysctl_max_syn_backlog,
.maxlen = sizeof(int),
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index aafec06..bb09c70 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6327,31 +6327,11 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
af_ops->init_seq_tsoff(skb, &tcp_rsk(req)->ts_off);
if (!want_cookie && !isn) {
- /* VJ's idea. We save last timestamp seen
- * from the destination in peer table, when entering
- * state TIME-WAIT, and check against it before
- * accepting new connection request.
- *
- * If "isn" is not zero, this request hit alive
- * timewait bucket, so that all the necessary checks
- * are made in the function processing timewait state.
- */
- if (net->ipv4.tcp_death_row.sysctl_tw_recycle) {
- bool strict;
-
- dst = af_ops->route_req(sk, &fl, req, &strict);
-
- if (dst && strict &&
- !tcp_peer_is_proven(req, dst)) {
- NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
- goto drop_and_release;
- }
- }
/* Kill the following clause, if you dislike this way. */
- else if (!net->ipv4.sysctl_tcp_syncookies &&
- (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
- (net->ipv4.sysctl_max_syn_backlog >> 2)) &&
- !tcp_peer_is_proven(req, dst)) {
+ if (!net->ipv4.sysctl_tcp_syncookies &&
+ (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
+ (net->ipv4.sysctl_max_syn_backlog >> 2)) &&
+ !tcp_peer_is_proven(req, dst)) {
/* Without syncookies last quarter of
* backlog is filled with destinations,
* proven to be alive.
@@ -6367,7 +6347,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
isn = af_ops->init_seq_tsoff(skb, &tcp_rsk(req)->ts_off);
}
if (!dst) {
- dst = af_ops->route_req(sk, &fl, req, NULL);
+ dst = af_ops->route_req(sk, &fl, req);
if (!dst)
goto drop_and_free;
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d8b401f..7482b5d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1213,19 +1213,9 @@ static void tcp_v4_init_req(struct request_sock *req,
static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
struct flowi *fl,
- const struct request_sock *req,
- bool *strict)
+ const struct request_sock *req)
{
- struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
-
- if (strict) {
- if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
- *strict = true;
- else
- *strict = false;
- }
-
- return dst;
+ return inet_csk_route_req(sk, &fl->u.ip4, req);
}
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
@@ -2462,7 +2452,6 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_tw_reuse = 0;
cnt = tcp_hashinfo.ehash_mask + 1;
- net->ipv4.tcp_death_row.sysctl_tw_recycle = 0;
net->ipv4.tcp_death_row.sysctl_max_tw_buckets = (cnt + 1) / 2;
net->ipv4.tcp_death_row.hashinfo = &tcp_hashinfo;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 853cb43..0f08d71 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -722,11 +722,8 @@ static void tcp_v6_init_req(struct request_sock *req,
static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
struct flowi *fl,
- const struct request_sock *req,
- bool *strict)
+ const struct request_sock *req)
{
- if (strict)
- *strict = true;
return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
}