diff options
| -rw-r--r-- | include/linux/snmp.h | 2 | ||||
| -rw-r--r-- | include/net/request_sock.h | 3 | ||||
| -rw-r--r-- | include/net/tcp.h | 3 | ||||
| -rw-r--r-- | net/ipv4/proc.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 49 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 31 |
6 files changed, 40 insertions, 50 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h index 12b2b18..e16557a 100644 --- a/include/linux/snmp.h +++ b/include/linux/snmp.h @@ -231,6 +231,8 @@ enum LINUX_MIB_TCPDEFERACCEPTDROP, LINUX_MIB_IPRPFILTER, /* IP Reverse Path Filter (rp_filter) */ LINUX_MIB_TCPTIMEWAITOVERFLOW, /* TCPTimeWaitOverflow */ + LINUX_MIB_TCPREQQFULLDOCOOKIES, /* TCPReqQFullDoCookies */ + LINUX_MIB_TCPREQQFULLDROP, /* TCPReqQFullDrop */ __LINUX_MIB_MAX }; diff --git a/include/net/request_sock.h b/include/net/request_sock.h index 99e6e19..4c0766e 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -96,7 +96,8 @@ extern int sysctl_max_syn_backlog; */ struct listen_sock { u8 max_qlen_log; - /* 3 bytes hole, try to use */ + u8 synflood_warned; + /* 2 bytes hole, try to use */ int qlen; int qlen_young; int clock_hand; diff --git a/include/net/tcp.h b/include/net/tcp.h index 149a415..e9b48b0 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -460,6 +460,9 @@ extern int tcp_write_wakeup(struct sock *); extern void tcp_send_fin(struct sock *sk); extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); extern int tcp_send_synack(struct sock *); +extern int tcp_syn_flood_action(struct sock *sk, + const struct sk_buff *skb, + const char *proto); extern void tcp_push_one(struct sock *, unsigned int mss_now); extern void tcp_send_ack(struct sock *sk); extern void tcp_send_delayed_ack(struct sock *sk); diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index b14ec7d..4bfad5d 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -254,6 +254,8 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPDeferAcceptDrop", LINUX_MIB_TCPDEFERACCEPTDROP), SNMP_MIB_ITEM("IPReversePathFilter", LINUX_MIB_IPRPFILTER), SNMP_MIB_ITEM("TCPTimeWaitOverflow", LINUX_MIB_TCPTIMEWAITOVERFLOW), + SNMP_MIB_ITEM("TCPReqQFullDoCookies", LINUX_MIB_TCPREQQFULLDOCOOKIES), + SNMP_MIB_ITEM("TCPReqQFullDrop", LINUX_MIB_TCPREQQFULLDROP), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1c12b8e..c34f015 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. @@ -1235,11 +1253,7 @@ 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 +1264,9 @@ 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 +1312,7 @@ 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) { diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index d1fb63f..3c9fa61 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -531,20 +531,6 @@ static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req, return tcp_v6_send_synack(sk, req, rvp); } -static inline void syn_flood_warning(struct sk_buff *skb) -{ -#ifdef CONFIG_SYN_COOKIES - if (sysctl_tcp_syncookies) - printk(KERN_INFO - "TCPv6: Possible SYN flooding on port %d. " - "Sending cookies.\n", ntohs(tcp_hdr(skb)->dest)); - else -#endif - printk(KERN_INFO - "TCPv6: Possible SYN flooding on port %d. " - "Dropping request.\n", ntohs(tcp_hdr(skb)->dest)); -} - static void tcp_v6_reqsk_destructor(struct request_sock *req) { kfree_skb(inet6_rsk(req)->pktopts); @@ -1179,11 +1165,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) struct tcp_sock *tp = tcp_sk(sk); __u32 isn = TCP_SKB_CB(skb)->when; struct dst_entry *dst = NULL; -#ifdef CONFIG_SYN_COOKIES int want_cookie = 0; -#else -#define want_cookie 0 -#endif if (skb->protocol == htons(ETH_P_IP)) return tcp_v4_conn_request(sk, skb); @@ -1192,14 +1174,9 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) goto drop; 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, "TCPv6"); + if (!want_cookie) + goto drop; } if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1) @@ -1249,9 +1226,7 @@ static int tcp_v6_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) { |
