tcp: Handle TCP SYN+ACK/ACK/RST transparency

[mirror_ubuntu-zesty-kernel.git] / net / ipv4 / tcp_ipv4.c

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d13688e3558d1a48728d32e13a38ba09309ec573..8b24bd833cb446fb84b927d38a0c815ebb0f6f50 100644 (file)
--- 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));