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Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
-rw-r--r--net/ipv4/tcp_ipv4.c60
1 files changed, 35 insertions, 25 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1c12b8e..7963e03 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -808,20 +808,38 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
kfree(inet_rsk(req)->opt);
}
-static void syn_flood_warning(const struct sk_buff *skb)
+/*
+ * Return 1 if a syncookie should be sent
+ */
+int tcp_syn_flood_action(struct sock *sk,
+ const struct sk_buff *skb,
+ const char *proto)
{
- const char *msg;
+ const char *msg = "Dropping request";
+ int want_cookie = 0;
+ struct listen_sock *lopt;
+
+
#ifdef CONFIG_SYN_COOKIES
- if (sysctl_tcp_syncookies)
+ if (sysctl_tcp_syncookies) {
msg = "Sending cookies";
- else
+ want_cookie = 1;
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
+ } else
#endif
- msg = "Dropping request";
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);
- pr_info("TCP: Possible SYN flooding on port %d. %s.\n",
- ntohs(tcp_hdr(skb)->dest), msg);
+ lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
+ if (!lopt->synflood_warned) {
+ lopt->synflood_warned = 1;
+ pr_info("%s: Possible SYN flooding on port %d. %s. "
+ " Check SNMP counters.\n",
+ proto, ntohs(tcp_hdr(skb)->dest), msg);
+ }
+ return want_cookie;
}
+EXPORT_SYMBOL(tcp_syn_flood_action);
/*
* Save and compile IPv4 options into the request_sock if needed.
@@ -909,18 +927,21 @@ int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
}
sk_nocaps_add(sk, NETIF_F_GSO_MASK);
}
- if (tcp_alloc_md5sig_pool(sk) == NULL) {
+
+ md5sig = tp->md5sig_info;
+ if (md5sig->entries4 == 0 &&
+ tcp_alloc_md5sig_pool(sk) == NULL) {
kfree(newkey);
return -ENOMEM;
}
- md5sig = tp->md5sig_info;
if (md5sig->alloced4 == md5sig->entries4) {
keys = kmalloc((sizeof(*keys) *
(md5sig->entries4 + 1)), GFP_ATOMIC);
if (!keys) {
kfree(newkey);
- tcp_free_md5sig_pool();
+ if (md5sig->entries4 == 0)
+ tcp_free_md5sig_pool();
return -ENOMEM;
}
@@ -964,6 +985,7 @@ int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
kfree(tp->md5sig_info->keys4);
tp->md5sig_info->keys4 = NULL;
tp->md5sig_info->alloced4 = 0;
+ tcp_free_md5sig_pool();
} else if (tp->md5sig_info->entries4 != i) {
/* Need to do some manipulation */
memmove(&tp->md5sig_info->keys4[i],
@@ -971,7 +993,6 @@ int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
(tp->md5sig_info->entries4 - i) *
sizeof(struct tcp4_md5sig_key));
}
- tcp_free_md5sig_pool();
return 0;
}
}
@@ -1235,11 +1256,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
__be32 saddr = ip_hdr(skb)->saddr;
__be32 daddr = ip_hdr(skb)->daddr;
__u32 isn = TCP_SKB_CB(skb)->when;
-#ifdef CONFIG_SYN_COOKIES
int want_cookie = 0;
-#else
-#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
-#endif
/* Never answer to SYNs send to broadcast or multicast */
if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
@@ -1250,14 +1267,9 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
* evidently real one.
*/
if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
- if (net_ratelimit())
- syn_flood_warning(skb);
-#ifdef CONFIG_SYN_COOKIES
- if (sysctl_tcp_syncookies) {
- want_cookie = 1;
- } else
-#endif
- goto drop;
+ want_cookie = tcp_syn_flood_action(sk, skb, "TCP");
+ if (!want_cookie)
+ goto drop;
}
/* Accept backlog is full. If we have already queued enough
@@ -1303,9 +1315,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
while (l-- > 0)
*c++ ^= *hash_location++;
-#ifdef CONFIG_SYN_COOKIES
want_cookie = 0; /* not our kind of cookie */
-#endif
tmp_ext.cookie_out_never = 0; /* false */
tmp_ext.cookie_plus = tmp_opt.cookie_plus;
} else if (!tp->rx_opt.cookie_in_always) {

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