From a3116ac5c216fc3c145906a46df9ce542ff7dcf2 Mon Sep 17 00:00:00 2001 From: KOVACS Krisztian Date: Wed, 1 Oct 2008 07:46:49 -0700 Subject: [PATCH] tcp: Port redirection support for TCP Current TCP code relies on the local port of the listening socket being the same as the destination address of the incoming connection. Port redirection used by many transparent proxying techniques obviously breaks this, so we have to store the original destination port address. This patch extends struct inet_request_sock and stores the incoming destination port value there. It also modifies the handshake code to use that value as the source port when sending reply packets. Signed-off-by: KOVACS Krisztian Signed-off-by: David S. Miller --- include/net/inet_sock.h | 2 +- include/net/tcp.h | 1 + net/ipv4/inet_connection_sock.c | 2 ++ net/ipv4/syncookies.c | 1 + net/ipv4/tcp_output.c | 2 +- 5 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index dced3f6..de0ecc7 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -61,8 +61,8 @@ struct inet_request_sock { struct request_sock req; #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) u16 inet6_rsk_offset; - /* 2 bytes hole, try to pack */ #endif + __be16 loc_port; __be32 loc_addr; __be32 rmt_addr; __be16 rmt_port; diff --git a/include/net/tcp.h b/include/net/tcp.h index 12c9b4f..f6cc341 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -976,6 +976,7 @@ static inline void tcp_openreq_init(struct request_sock *req, ireq->acked = 0; ireq->ecn_ok = 0; ireq->rmt_port = tcp_hdr(skb)->source; + ireq->loc_port = tcp_hdr(skb)->dest; } extern void tcp_enter_memory_pressure(struct sock *sk); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 432c570..21fcc5a 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -516,6 +516,8 @@ struct sock *inet_csk_clone(struct sock *sk, const struct request_sock *req, newicsk->icsk_bind_hash = NULL; inet_sk(newsk)->dport = inet_rsk(req)->rmt_port; + inet_sk(newsk)->num = ntohs(inet_rsk(req)->loc_port); + inet_sk(newsk)->sport = inet_rsk(req)->loc_port; newsk->sk_write_space = sk_stream_write_space; newicsk->icsk_retransmits = 0; diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 929302b..d346c22 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -297,6 +297,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, treq->rcv_isn = ntohl(th->seq) - 1; treq->snt_isn = cookie; req->mss = mss; + ireq->loc_port = th->dest; ireq->rmt_port = th->source; ireq->loc_addr = ip_hdr(skb)->daddr; ireq->rmt_addr = ip_hdr(skb)->saddr; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index a8499ef..493553c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2275,7 +2275,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, th->syn = 1; th->ack = 1; TCP_ECN_make_synack(req, th); - th->source = inet_sk(sk)->sport; + th->source = ireq->loc_port; th->dest = ireq->rmt_port; /* Setting of flags are superfluous here for callers (and ECE is * not even correctly set) -- 2.7.4