[DCCP]: Introduce DCCP_SOCKOPT_SERVICE

As discussed in the dccp@vger mailing list:

Now applications have to use setsockopt(DCCP_SOCKOPT_SERVICE, service[s]),
prior to calling listen() and connect().

An array of unsigned ints can be passed meaning that the listening sock accepts
connection requests for several services.

With this we can ditch struct sockaddr_dccp and use only sockaddr_in (and
sockaddr_in6 in the future).

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dccp/output.c b/net/dccp/output.c
index ea6d0e9..156b1d2 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -85,7 +85,7 @@
 		switch (dcb->dccpd_type) {
 		case DCCP_PKT_REQUEST:
 			dccp_hdr_request(skb)->dccph_req_service =
-							dcb->dccpd_service;
+							dp->dccps_service;
 			break;
 		case DCCP_PKT_RESET:
 			dccp_hdr_reset(skb)->dccph_reset_code =
@@ -270,6 +270,7 @@
 				   struct request_sock *req)
 {
 	struct dccp_hdr *dh;
+	struct dccp_request_sock *dreq;
 	const int dccp_header_size = sizeof(struct dccp_hdr) +
 				     sizeof(struct dccp_hdr_ext) +
 				     sizeof(struct dccp_hdr_response);
@@ -285,8 +286,9 @@
 	skb->dst = dst_clone(dst);
 	skb->csum = 0;
 
+	dreq = dccp_rsk(req);
 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
-	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_rsk(req)->dreq_iss;
+	DCCP_SKB_CB(skb)->dccpd_seq  = dreq->dreq_iss;
 	dccp_insert_options(sk, skb);
 
 	skb->h.raw = skb_push(skb, dccp_header_size);
@@ -300,8 +302,9 @@
 			   DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
 	dh->dccph_type	= DCCP_PKT_RESPONSE;
 	dh->dccph_x	= 1;
-	dccp_hdr_set_seq(dh, dccp_rsk(req)->dreq_iss);
-	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dccp_rsk(req)->dreq_isr);
+	dccp_hdr_set_seq(dh, dreq->dreq_iss);
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr);
+	dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service;
 
 	dh->dccph_checksum = dccp_v4_checksum(skb, inet_rsk(req)->loc_addr,
 					      inet_rsk(req)->rmt_addr);
@@ -397,9 +400,6 @@
 	skb_reserve(skb, MAX_DCCP_HEADER);
 
 	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
-	/* FIXME: set service to something meaningful, coming
-	 * from userspace*/
-	DCCP_SKB_CB(skb)->dccpd_service = 0;
 	skb->csum = 0;
 	skb_set_owner_w(skb, sk);