All of lore.kernel.org
 help / color / mirror / Atom feed
From: KOVACS Krisztian <hidden@sch.bme.hu>
To: David Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>, netdev@vger.kernel.org
Subject: [PATCH 05/14] Handle TCP SYN+ACK/ACK/RST transparency
Date: Sat, 13 Oct 2007 19:31:33 +0200	[thread overview]
Message-ID: <20071013173133.22517.41466.stgit@nessa.odu> (raw)
In-Reply-To: <20071013172857.22517.84760.stgit@nessa.odu>

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 <hidden@sch.bme.hu>
---

 include/net/inet_sock.h         |    8 +++++++-
 include/net/ip.h                |    9 +++++++++
 net/ipv4/inet_connection_sock.c |    1 +
 net/ipv4/ip_output.c            |    4 +++-
 net/ipv4/syncookies.c           |    1 +
 net/ipv4/tcp_ipv4.c             |   11 ++++++++---
 6 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index e86832d..517efe7 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;
 };
 
@@ -191,4 +192,9 @@ static inline int inet_sk_ehashfn(const struct sock *sk)
 	return inet_ehashfn(laddr, lport, faddr, fport);
 }
 
+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 3af3ed9..5ea3813 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -29,6 +29,7 @@
 
 #include <net/inet_sock.h>
 #include <net/snmp.h>
+#include <net/flow.h>
 
 struct sock;
 
@@ -140,12 +141,20 @@ 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
+
+static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
+{
+	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
+}
+
 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 		   unsigned int len); 
 
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 3cef128..1667cd8 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -335,6 +335,7 @@ struct dst_entry* inet_csk_route_req(struct sock *sk,
 					.saddr = ireq->loc_addr,
 					.tos = RT_CONN_FLAGS(sk) } },
 			    .proto = sk->sk_protocol,
+			    .flags = inet_sk_flowi_flags(sk),
 			    .uli_u = { .ports =
 				       { .sport = inet_sk(sk)->sport,
 					 .dport = ireq->rmt_port } } };
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 699f067..62b31ae 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -322,6 +322,7 @@ int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
 							.saddr = inet->saddr,
 							.tos = RT_CONN_FLAGS(sk) } },
 					    .proto = sk->sk_protocol,
+					    .flags = inet_sk_flowi_flags(sk),
 					    .uli_u = { .ports =
 						       { .sport = inet->sport,
 							 .dport = inet->dport } } };
@@ -1368,7 +1369,8 @@ void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *ar
 				    .uli_u = { .ports =
 					       { .sport = tcp_hdr(skb)->dest,
 						 .dport = tcp_hdr(skb)->source } },
-				    .proto = sk->sk_protocol };
+				    .proto = sk->sk_protocol,
+				    .flags = ip_reply_arg_flowi_flags(arg) };
 		security_skb_classify_flow(skb, &fl);
 		if (ip_route_output_key(&rt, &fl))
 			return;
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 2da1be0..a0f6fdb 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -260,6 +260,7 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb,
 						.saddr = ireq->loc_addr,
 						.tos = RT_CONN_FLAGS(sk) } },
 				    .proto = IPPROTO_TCP,
+				    .flags = inet_sk_flowi_flags(sk),
 				    .uli_u = { .ports =
 					       { .sport = th->dest,
 						 .dport = th->source } } };
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 38cf73a..fb471b0 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -613,6 +613,7 @@ 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;
 
 	ip_send_reply(tcp_socket->sk, skb, &arg, arg.iov[0].iov_len);
 
@@ -626,7 +627,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
 
 static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
 			    struct sk_buff *skb, u32 seq, u32 ack,
-			    u32 win, u32 ts)
+			    u32 win, u32 ts, int reply_flags)
 {
 	struct tcphdr *th = tcp_hdr(skb);
 	struct {
@@ -702,6 +703,7 @@ static void tcp_v4_send_ack(struct tcp_timewait_sock *twsk,
 					arg.iov[0].iov_len);
 	}
 #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);
@@ -721,7 +723,8 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
 	tcp_v4_send_ack(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
-			tcptw->tw_ts_recent);
+			tcptw->tw_ts_recent,
+			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0);
 
 	inet_twsk_put(tw);
 }
@@ -731,7 +734,8 @@ static void tcp_v4_reqsk_send_ack(struct sk_buff *skb,
 {
 	tcp_v4_send_ack(NULL, skb, tcp_rsk(req)->snt_isn + 1,
 			tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
-			req->ts_recent);
+			req->ts_recent,
+			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
 }
 
 /*
@@ -1333,6 +1337,7 @@ 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));


  parent reply	other threads:[~2007-10-13 18:39 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-13 17:28 [PATCH 00/14] Transparent Proxying Patches, Take 5 KOVACS Krisztian
2007-10-13 17:29 ` [PATCH 01/14] Loosen source address check on IPv4 output KOVACS Krisztian
2007-10-13 17:29 ` [PATCH 02/14] Implement IP_TRANSPARENT socket option KOVACS Krisztian
2007-10-13 17:30 ` [PATCH 03/14] Allow binding to non-local addresses if IP_TRANSPARENT is set KOVACS Krisztian
2007-10-13 17:31 ` [PATCH 04/14] Conditionally enable transparent flow flag when connecting KOVACS Krisztian
2007-10-13 17:31 ` KOVACS Krisztian [this message]
2007-10-13 17:32 ` [PATCH 06/14] Port redirection support for TCP KOVACS Krisztian
2007-10-13 17:32 ` [PATCH 07/14] Export UDP socket lookup function KOVACS Krisztian
2007-10-13 17:33 ` [PATCH 08/14] Split Netfilter IPv4 defragmentation into a separate module KOVACS Krisztian
2007-10-13 17:33 ` [PATCH 09/14] iptables tproxy core KOVACS Krisztian
2007-10-13 17:34 ` [PATCH 10/14] iptables socket match KOVACS Krisztian
2007-10-13 17:34 ` [PATCH 11/14] iptables TPROXY target KOVACS Krisztian
2007-10-13 17:35 ` [PATCH 12/14] Don't lookup the socket if there's a socket attached to the skb KOVACS Krisztian
2007-10-13 17:35 ` [PATCH 13/14] " KOVACS Krisztian
2007-10-13 17:36 ` [PATCH 14/14] Add documentation KOVACS Krisztian
2007-10-13 22:44 ` [PATCH 00/14] Transparent Proxying Patches, Take 5 David Miller
2007-10-14  9:05   ` KOVACS Krisztian

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20071013173133.22517.41466.stgit@nessa.odu \
    --to=hidden@sch.bme.hu \
    --cc=davem@davemloft.net \
    --cc=kaber@trash.net \
    --cc=netdev@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.