ipv4: Namespaceify tcp syncookies sysctl knob

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 9e83084..ac000fc 100644 (file)
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -101,6 +101,8 @@ 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 05659e8..1fb23b7 100644 (file)
--- 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 643a86c..ba0dcff 100644 (file)
--- 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 bb682e3..d801425 100644 (file)
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -341,15 +341,6 @@ 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,
@@ -960,6 +951,15 @@ 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 596c1cb..b17aba4 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6163,9 +6163,10 @@ 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);
@@ -6174,7 +6175,7 @@ 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);
@@ -6207,6 +6208,7 @@ 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;
@@ -6217,7 +6219,7 @@ 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)
@@ -6283,7 +6285,7 @@ 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 3146279..98313d1 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -860,7 +860,6 @@ 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
@@ -2391,6 +2390,8 @@ 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 75632a9..fadd8b9 100644 (file)
--- 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 2906ef2..0e393ff 100644 (file)
--- 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))