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Date: Sat, 13 Oct 2007 19:31:33 +0200
From: KOVACS Krisztian <hidden@....bme.hu>
To: David Miller <davem@...emloft.net>
Cc: Patrick McHardy <kaber@...sh.net>, netdev@...r.kernel.org
Subject: [PATCH 05/14] 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 <hidden@....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));
-
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