[PATCH 3/9] ipv4: Namespaceify tcp syncookies sysctl knob
From: Nikolay Borisov
Date: Mon Jan 11 2016 - 04:54:46 EST
Signed-off-by: Nikolay Borisov <kernel@xxxxxxxx>
---
include/net/netns/ipv4.h | 2 ++
include/net/tcp.h | 1 -
net/ipv4/syncookies.c | 4 +---
net/ipv4/sysctl_net_ipv4.c | 18 +++++++++---------
net/ipv4/tcp_input.c | 10 ++++++----
net/ipv4/tcp_ipv4.c | 3 ++-
net/ipv4/tcp_minisocks.c | 3 ---
net/ipv6/syncookies.c | 2 +-
8 files changed, 21 insertions(+), 22 deletions(-)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index bca049102441..80da0d095eaf 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -98,6 +98,8 @@ struct netns_ipv4 {
int sysctl_tcp_syn_retries;
int sysctl_tcp_synack_retries;
+ int sysctl_tcp_syncookies;
+
struct ping_group_range ping_group_range;
atomic_t dev_addr_genid;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5a162875e80c..5497cc809601 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -243,7 +243,6 @@ extern int sysctl_tcp_fin_timeout;
extern int sysctl_tcp_retries1;
extern int sysctl_tcp_retries2;
extern int sysctl_tcp_orphan_retries;
-extern int sysctl_tcp_syncookies;
extern int sysctl_tcp_fastopen;
extern int sysctl_tcp_retrans_collapse;
extern int sysctl_tcp_stdurg;
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 4cbe9f0a4281..1c2bfda72c07 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -19,8 +19,6 @@
#include <net/tcp.h>
#include <net/route.h>
-extern int sysctl_tcp_syncookies;
-
static u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS] __read_mostly;
#define COOKIEBITS 24 /* Upper bits store count */
@@ -307,7 +305,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
__u8 rcv_wscale;
struct flowi4 fl4;
- if (!sysctl_tcp_syncookies || !th->ack || th->rst)
+ if (!sock_net(sk)->ipv4.sysctl_tcp_syncookies || !th->ack || th->rst)
goto out;
if (tcp_synq_no_recent_overflow(sk))
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 5dd89de5bf8d..007b9f8f7a2a 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -342,15 +342,6 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
-#ifdef CONFIG_SYN_COOKIES
- {
- .procname = "tcp_syncookies",
- .data = &sysctl_tcp_syncookies,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec
- },
-#endif
{
.procname = "tcp_fastopen",
.data = &sysctl_tcp_fastopen,
@@ -950,6 +941,15 @@ static struct ctl_table ipv4_net_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
+#ifdef CONFIG_SYN_COOKIES
+ {
+ .procname = "tcp_syncookies",
+ .data = &init_net.ipv4.sysctl_tcp_syncookies,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+#endif
{ }
};
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2d656eef7f8e..dc8fe6c8a2e0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6114,9 +6114,10 @@ static bool tcp_syn_flood_action(const struct sock *sk,
struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
const char *msg = "Dropping request";
bool want_cookie = false;
+ struct net *net = sock_net(sk);
#ifdef CONFIG_SYN_COOKIES
- if (sysctl_tcp_syncookies) {
+ if (net->ipv4.sysctl_tcp_syncookies) {
msg = "Sending cookies";
want_cookie = true;
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
@@ -6125,7 +6126,7 @@ static bool tcp_syn_flood_action(const struct sock *sk,
NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
if (!queue->synflood_warned &&
- sysctl_tcp_syncookies != 2 &&
+ net->ipv4.sysctl_tcp_syncookies != 2 &&
xchg(&queue->synflood_warned, 1) == 0)
pr_info("%s: Possible SYN flooding on port %d. %s. Check SNMP counters.\n",
proto, ntohs(tcp_hdr(skb)->dest), msg);
@@ -6158,6 +6159,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
__u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
struct tcp_options_received tmp_opt;
struct tcp_sock *tp = tcp_sk(sk);
+ struct net *net = sock_net(sk);
struct sock *fastopen_sk = NULL;
struct dst_entry *dst = NULL;
struct request_sock *req;
@@ -6168,7 +6170,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
* limitations, they conserve resources and peer is
* evidently real one.
*/
- if ((sysctl_tcp_syncookies == 2 ||
+ if ((net->ipv4.sysctl_tcp_syncookies == 2 ||
inet_csk_reqsk_queue_is_full(sk)) && !isn) {
want_cookie = tcp_syn_flood_action(sk, skb, rsk_ops->slab_name);
if (!want_cookie)
@@ -6234,7 +6236,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
}
}
/* Kill the following clause, if you dislike this way. */
- else if (!sysctl_tcp_syncookies &&
+ else if (!net->ipv4.sysctl_tcp_syncookies &&
(sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
(sysctl_max_syn_backlog >> 2)) &&
!tcp_peer_is_proven(req, dst, false,
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a5268576021c..ee3566377717 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -855,7 +855,6 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
kfree(inet_rsk(req)->opt);
}
-
#ifdef CONFIG_TCP_MD5SIG
/*
* RFC2385 MD5 checksumming requires a mapping of
@@ -2385,6 +2384,8 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
+ net->ipv4.sysctl_tcp_syncookies = 0;
+
return 0;
fail:
tcp_sk_exit(net);
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index ac6b1961ffeb..c6555f97c628 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -27,9 +27,6 @@
#include <net/inet_common.h>
#include <net/xfrm.h>
-int sysctl_tcp_syncookies __read_mostly = 1;
-EXPORT_SYMBOL(sysctl_tcp_syncookies);
-
int sysctl_tcp_abort_on_overflow __read_mostly;
struct inet_timewait_death_row tcp_death_row = {
diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c
index eaf7ac496d50..0c306adc166e 100644
--- a/net/ipv6/syncookies.c
+++ b/net/ipv6/syncookies.c
@@ -148,7 +148,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
struct dst_entry *dst;
__u8 rcv_wscale;
- if (!sysctl_tcp_syncookies || !th->ack || th->rst)
+ if (!sock_net(sk)->ipv4.sysctl_tcp_syncookies || !th->ack || th->rst)
goto out;
if (tcp_synq_no_recent_overflow(sk))
--
2.5.0