diff options
| -rw-r--r-- | include/linux/snmp.h | 2 | ||||
| -rw-r--r-- | net/ipv4/proc.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 32 |
3 files changed, 17 insertions, 19 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h index 594638ec5ac..a33f70fa1bf 100644 --- a/include/linux/snmp.h +++ b/include/linux/snmp.h @@ -208,7 +208,6 @@ enum LINUX_MIB_TCPDSACKOFOSENT, /* TCPDSACKOfoSent */ LINUX_MIB_TCPDSACKRECV, /* TCPDSACKRecv */ LINUX_MIB_TCPDSACKOFORECV, /* TCPDSACKOfoRecv */ - LINUX_MIB_TCPABORTONSYN, /* TCPAbortOnSyn */ LINUX_MIB_TCPABORTONDATA, /* TCPAbortOnData */ LINUX_MIB_TCPABORTONCLOSE, /* TCPAbortOnClose */ LINUX_MIB_TCPABORTONMEMORY, /* TCPAbortOnMemory */ @@ -235,6 +234,7 @@ enum LINUX_MIB_TCPRETRANSFAIL, /* TCPRetransFail */ LINUX_MIB_TCPRCVCOALESCE, /* TCPRcvCoalesce */ LINUX_MIB_TCPCHALLENGEACK, /* TCPChallengeACK */ + LINUX_MIB_TCPSYNCHALLENGE, /* TCPSYNChallenge */ __LINUX_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index d589468fd40..212897517b8 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -232,7 +232,6 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPDSACKOfoSent", LINUX_MIB_TCPDSACKOFOSENT), SNMP_MIB_ITEM("TCPDSACKRecv", LINUX_MIB_TCPDSACKRECV), SNMP_MIB_ITEM("TCPDSACKOfoRecv", LINUX_MIB_TCPDSACKOFORECV), - SNMP_MIB_ITEM("TCPAbortOnSyn", LINUX_MIB_TCPABORTONSYN), SNMP_MIB_ITEM("TCPAbortOnData", LINUX_MIB_TCPABORTONDATA), SNMP_MIB_ITEM("TCPAbortOnClose", LINUX_MIB_TCPABORTONCLOSE), SNMP_MIB_ITEM("TCPAbortOnMemory", LINUX_MIB_TCPABORTONMEMORY), @@ -259,6 +258,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPRetransFail", LINUX_MIB_TCPRETRANSFAIL), SNMP_MIB_ITEM("TCPRcvCoalesce", LINUX_MIB_TCPRCVCOALESCE), SNMP_MIB_ITEM("TCPChallengeACK", LINUX_MIB_TCPCHALLENGEACK), + SNMP_MIB_ITEM("TCPSYNChallenge", LINUX_MIB_TCPSYNCHALLENGE), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 390541858e4..2dc2e153132 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5288,8 +5288,8 @@ static void tcp_send_challenge_ack(struct sock *sk) /* Does PAWS and seqno based validation of an incoming segment, flags will * play significant role here. */ -static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, - const struct tcphdr *th, int syn_inerr) +static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, + const struct tcphdr *th, int syn_inerr) { const u8 *hash_location; struct tcp_sock *tp = tcp_sk(sk); @@ -5341,20 +5341,22 @@ static int tcp_validate_incoming(struct sock *sk, struct sk_buff *skb, /* step 3: check security and precedence [ignored] */ - /* step 4: Check for a SYN in window. */ - if (th->syn && !before(TCP_SKB_CB(skb)->seq, tp->rcv_nxt)) { + /* step 4: Check for a SYN + * RFC 5691 4.2 : Send a challenge ack + */ + if (th->syn) { if (syn_inerr) TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS); - NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONSYN); - tcp_reset(sk); - return -1; + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNCHALLENGE); + tcp_send_challenge_ack(sk); + goto discard; } - return 1; + return true; discard: __kfree_skb(skb); - return 0; + return false; } /* @@ -5384,7 +5386,6 @@ int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct tcphdr *th, unsigned int len) { struct tcp_sock *tp = tcp_sk(sk); - int res; /* * Header prediction. @@ -5564,9 +5565,8 @@ slow_path: * Standard slow path. */ - res = tcp_validate_incoming(sk, skb, th, 1); - if (res <= 0) - return -res; + if (!tcp_validate_incoming(sk, skb, th, 1)) + return 0; step5: if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0) @@ -5876,7 +5876,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); int queued = 0; - int res; tp->rx_opt.saw_tstamp = 0; @@ -5931,9 +5930,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, return 0; } - res = tcp_validate_incoming(sk, skb, th, 0); - if (res <= 0) - return -res; + if (!tcp_validate_incoming(sk, skb, th, 0)) + return 0; /* step 5: check the ACK field */ if (th->ack) { |