Commit a3116ac5 authored by KOVACS Krisztian's avatar KOVACS Krisztian Committed by David S. Miller

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: default avatarKOVACS Krisztian <hidden@sch.bme.hu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 86b08d86
......@@ -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;
......
......@@ -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);
......
......@@ -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;
......
......@@ -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;
......
......@@ -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)
......
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