dccp: Port redirection support for DCCP

Commit a3116ac5c2 from 1st October ("tcp: Port
redirection support for TCP") broke DCCP skb lookup by changing inet_csk_clone,
which is used by DCCP to generate the child socket after the handshake.

This patch updates DCCP to use 'loc_port' instead of 'sport', which fixes the
problem, and thus inheriting port redirection support via the new interface.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/ipv6.c

@@ -259,7 +259,7 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req)
 	fl.fl6_flowlabel = 0;
 	fl.oif = ireq6->iif;
 	fl.fl_ip_dport = inet_rsk(req)->rmt_port;
-	fl.fl_ip_sport = inet_sk(sk)->sport;
+	fl.fl_ip_sport = inet_rsk(req)->loc_port;
 	security_req_classify_flow(req, &fl);
 
 	opt = np->opt;
@@ -558,7 +558,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 		ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
 		fl.oif = sk->sk_bound_dev_if;
 		fl.fl_ip_dport = inet_rsk(req)->rmt_port;
-		fl.fl_ip_sport = inet_sk(sk)->sport;
+		fl.fl_ip_sport = inet_rsk(req)->loc_port;
 		security_sk_classify_flow(sk, &fl);
 
 		if (ip6_dst_lookup(sk, &dst, &fl))

net/dccp/minisocks.c

@@ -309,6 +309,7 @@ void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb)
 	struct dccp_request_sock *dreq = dccp_rsk(req);
 
 	inet_rsk(req)->rmt_port	  = dccp_hdr(skb)->dccph_sport;
+	inet_rsk(req)->loc_port	  = dccp_hdr(skb)->dccph_dport;
 	inet_rsk(req)->acked	  = 0;
 	req->rcv_wnd		  = sysctl_dccp_feat_sequence_window;
 	dreq->dreq_timestamp_echo = 0;

net/dccp/output.c

@@ -347,7 +347,7 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 	/* Build and checksum header */
 	dh = dccp_zeroed_hdr(skb, dccp_header_size);
 
-	dh->dccph_sport	= inet_sk(sk)->sport;
+	dh->dccph_sport	= inet_rsk(req)->loc_port;
 	dh->dccph_dport	= inet_rsk(req)->rmt_port;
 	dh->dccph_doff	= (dccp_header_size +
 			   DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;