From 88ef4a5a78e63420dd1dd770f1bd1dc198926b04 Mon Sep 17 00:00:00 2001 From: KOVACS Krisztian Date: Wed, 1 Oct 2008 07:41:00 -0700 Subject: [PATCH] tcp: Handle TCP SYN+ACK/ACK/RST transparency The TCP stack sends out SYN+ACK/ACK/RST reply packets in response to incoming packets. The non-local source address check on output bites us again, as replies for transparently redirected traffic won't have a chance to leave the node. This patch selectively sets the FLOWI_FLAG_ANYSRC flag when doing the route lookup for those replies. Transparent replies are enabled if the listening socket has the transparent socket flag set. Signed-off-by: KOVACS Krisztian Signed-off-by: David S. Miller --- include/net/inet_sock.h | 8 +++++++- include/net/ip.h | 3 +++ net/ipv4/tcp_ipv4.c | 12 +++++++++--- 3 files changed, 19 insertions(+), 4 deletions(-) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index 139b78b4dfeb..dced3f64f975 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -72,7 +72,8 @@ struct inet_request_sock { sack_ok : 1, wscale_ok : 1, ecn_ok : 1, - acked : 1; + acked : 1, + no_srccheck: 1; struct ip_options *opt; }; @@ -204,4 +205,9 @@ static inline struct request_sock *inet_reqsk_alloc(struct request_sock_ops *ops return req; } +static inline __u8 inet_sk_flowi_flags(const struct sock *sk) +{ + return inet_sk(sk)->transparent ? FLOWI_FLAG_ANYSRC : 0; +} + #endif /* _INET_SOCK_H */ diff --git a/include/net/ip.h b/include/net/ip.h index 250e6ef025a4..90b27f634b76 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -140,12 +140,15 @@ static inline void ip_tr_mc_map(__be32 addr, char *buf) struct ip_reply_arg { struct kvec iov[1]; + int flags; __wsum csum; int csumoffset; /* u16 offset of csum in iov[0].iov_base */ /* -1 if not needed */ int bound_dev_if; }; +#define IP_REPLY_ARG_NOSRCCHECK 1 + void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, unsigned int len); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index d13688e3558d..8b24bd833cb4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -591,6 +591,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) ip_hdr(skb)->saddr, /* XXX */ sizeof(struct tcphdr), IPPROTO_TCP, 0); arg.csumoffset = offsetof(struct tcphdr, check) / 2; + arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; net = dev_net(skb->dst->dev); ip_send_reply(net->ipv4.tcp_sock, skb, @@ -606,7 +607,8 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts, int oif, - struct tcp_md5sig_key *key) + struct tcp_md5sig_key *key, + int reply_flags) { struct tcphdr *th = tcp_hdr(skb); struct { @@ -659,6 +661,7 @@ static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack, ip_hdr(skb)->daddr, &rep.th); } #endif + arg.flags = reply_flags; arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, ip_hdr(skb)->saddr, /* XXX */ arg.iov[0].iov_len, IPPROTO_TCP, 0); @@ -681,7 +684,8 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcptw->tw_ts_recent, tw->tw_bound_dev_if, - tcp_twsk_md5_key(tcptw) + tcp_twsk_md5_key(tcptw), + tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0 ); inet_twsk_put(tw); @@ -694,7 +698,8 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent, 0, - tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr)); + tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr), + inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0); } /* @@ -1244,6 +1249,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) ireq = inet_rsk(req); ireq->loc_addr = daddr; ireq->rmt_addr = saddr; + ireq->no_srccheck = inet_sk(sk)->transparent; ireq->opt = tcp_v4_save_options(sk, skb); if (!want_cookie) TCP_ECN_create_request(req, tcp_hdr(skb)); -- 2.20.1