[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>

include/linux/dccp.h

@@ -4,16 +4,6 @@
 #include <linux/types.h>
 #include <asm/byteorder.h>
 
-/* Structure describing an Internet (DCCP) socket address. */
-struct sockaddr_dccp {
-	__u16	sdccp_family;	/* Address family   */
-	__u16	sdccp_port;	/* Port number	    */
-	__u32	sdccp_addr;	/* Internet address */
-	__u32	sdccp_service;	/* Service	    */
-	/* Pad to size of `struct sockaddr': 16 bytes . */
-	__u32	sdccp_pad;
-};
-
 /**
  * struct dccp_hdr - generic part of DCCP packet header
  *
@@ -188,6 +178,9 @@ enum {
 
 /* DCCP socket options */
 #define DCCP_SOCKOPT_PACKET_SIZE	1
+#define DCCP_SOCKOPT_SERVICE		2
+
+#define DCCP_SERVICE_LIST_MAX_LEN      32
 
 #ifdef __KERNEL__
 
@@ -382,6 +375,25 @@ enum dccp_role {
 	DCCP_ROLE_SERVER,
 };
 
+struct dccp_service_list {
+	__u32	dccpsl_nr;
+	__u32	dccpsl_list[0];
+};
+
+#define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)
+
+static inline int dccp_list_has_service(const struct dccp_service_list *sl,
+					const u32 service)
+{
+	if (likely(sl != NULL)) {
+		u32 i = sl->dccpsl_nr;
+		while (i--)
+			if (sl->dccpsl_list[i] == service)
+				return 1; 
+	}
+	return 0;
+}
+
 /**
  * struct dccp_sock - DCCP socket state
  *
@@ -417,7 +429,8 @@ struct dccp_sock {
 	__u64				dccps_gss;
 	__u64				dccps_gsr;
 	__u64				dccps_gar;
-	unsigned long			dccps_service;
+	__u32				dccps_service;
+	struct dccp_service_list	*dccps_service_list;
 	struct timeval			dccps_timestamp_time;
 	__u32				dccps_timestamp_echo;
 	__u32				dccps_packet_size;
@@ -443,6 +456,11 @@ static inline struct dccp_sock *dccp_sk(const struct sock *sk)
 	return (struct dccp_sock *)sk;
 }
 
+static inline int dccp_service_not_initialized(const struct sock *sk)
+{
+	return dccp_sk(sk)->dccps_service == DCCP_SERVICE_INVALID_VALUE;
+}
+
 static inline const char *dccp_role(const struct sock *sk)
 {
 	switch (dccp_sk(sk)->dccps_role) {

net/dccp/dccp.h

@@ -258,13 +258,12 @@ extern int	   dccp_v4_send_reset(struct sock *sk,
 extern void	   dccp_send_close(struct sock *sk, const int active);
 
 struct dccp_skb_cb {
-	__u8 dccpd_type;
+	__u8  dccpd_type:4;
+	__u8  dccpd_ccval:4;
 	__u8  dccpd_reset_code;
-	__u8 dccpd_service;
-	__u8 dccpd_ccval;
+	__u16 dccpd_opt_len;
 	__u64 dccpd_seq;
 	__u64 dccpd_ack_seq;
-	int  dccpd_opt_len;
 };
 
 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))

net/dccp/ipv4.c

@@ -246,6 +246,9 @@ static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 
 	dp->dccps_role = DCCP_ROLE_CLIENT;
 
+	if (dccp_service_not_initialized(sk))
+		return -EPROTO;
+
 	if (addr_len < sizeof(struct sockaddr_in))
 		return -EINVAL;
 
@@ -661,6 +664,16 @@ static inline u64 dccp_v4_init_sequence(const struct sock *sk,
 					   dccp_hdr(skb)->dccph_sport);
 }
 
+static inline int dccp_bad_service_code(const struct sock *sk,
+					const __u32 service)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+
+	if (dp->dccps_service == service)
+		return 0;
+	return !dccp_list_has_service(dp->dccps_service_list, service);
+}
+
 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 {
 	struct inet_request_sock *ireq;
@@ -669,6 +682,7 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	struct dccp_request_sock *dreq;
 	const __u32 saddr = skb->nh.iph->saddr;
 	const __u32 daddr = skb->nh.iph->daddr;
+ 	const __u32 service = dccp_hdr_request(skb)->dccph_req_service;
 	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 	__u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
 	struct dst_entry *dst = NULL;
@@ -680,6 +694,10 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 		goto drop;
 	}
 
+	if (dccp_bad_service_code(sk, service)) {
+		reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+		goto drop;
+ 	}
 	/*
 	 * TW buckets are converted to open requests without
 	 * limitations, they conserve resources and peer is
@@ -724,7 +742,7 @@ int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	dreq = dccp_rsk(req);
 	dreq->dreq_isr	   = dcb->dccpd_seq;
 	dreq->dreq_iss	   = dccp_v4_init_sequence(sk, skb);
-	dreq->dreq_service = dccp_hdr_request(skb)->dccph_req_service;
+	dreq->dreq_service = service;
 
 	if (dccp_v4_send_response(sk, req, dst))
 		goto drop_and_free;
@@ -1284,6 +1302,7 @@ static int dccp_v4_init_sock(struct sock *sk)
 	sk->sk_write_space = dccp_write_space;
 	dp->dccps_mss_cache = 536;
 	dp->dccps_role = DCCP_ROLE_UNDEFINED;
+	dp->dccps_service = DCCP_SERVICE_INVALID_VALUE;
 
 	return 0;
 }
@@ -1305,6 +1324,11 @@ static int dccp_v4_destroy_sock(struct sock *sk)
 	if (inet_csk(sk)->icsk_bind_hash != NULL)
 		inet_put_port(&dccp_hashinfo, sk);
 
+	if (dp->dccps_service_list != NULL) {
+		kfree(dp->dccps_service_list);
+		dp->dccps_service_list = NULL;
+	}
+
 	ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
 	ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
 	dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);

net/dccp/minisocks.c

@@ -93,8 +93,10 @@ struct sock *dccp_create_openreq_child(struct sock *sk,
 		struct inet_connection_sock *newicsk = inet_csk(sk);
 		struct dccp_sock *newdp = dccp_sk(newsk);
 
-		newdp->dccps_hc_rx_ackpkts = NULL;
 		newdp->dccps_role	   = DCCP_ROLE_SERVER;
+		newdp->dccps_hc_rx_ackpkts = NULL;
+		newdp->dccps_service_list  = NULL;
+		newdp->dccps_service	   = dreq->dreq_service;
 		newicsk->icsk_rto	   = DCCP_TIMEOUT_INIT;
 		do_gettimeofday(&newdp->dccps_epoch);
 

net/dccp/output.c

@@ -85,7 +85,7 @@ int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 		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 sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 				   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 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 	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 @@ struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst,
 			   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 @@ int dccp_connect(struct sock *sk)
 	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);
 

net/dccp/proto.c

@@ -94,7 +94,15 @@ EXPORT_SYMBOL_GPL(dccp_state_name);
 
 static inline int dccp_listen_start(struct sock *sk)
 {
-	dccp_sk(sk)->dccps_role = DCCP_ROLE_LISTEN;
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	dp->dccps_role = DCCP_ROLE_LISTEN;
+	/*
+	 * Apps need to use setsockopt(DCCP_SOCKOPT_SERVICE)
+	 * before calling listen()
+	 */
+	if (dccp_service_not_initialized(sk))
+		return -EPROTO;
 	return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
 }
 
@@ -202,6 +210,42 @@ int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 	return -ENOIOCTLCMD;
 }
 
+static int dccp_setsockopt_service(struct sock *sk, const u32 service,
+				   char __user *optval, int optlen)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct dccp_service_list *sl = NULL;
+
+	if (service == DCCP_SERVICE_INVALID_VALUE || 
+	    optlen > DCCP_SERVICE_LIST_MAX_LEN * sizeof(u32))
+		return -EINVAL;
+
+	if (optlen > sizeof(service)) {
+		sl = kmalloc(optlen, GFP_KERNEL);
+		if (sl == NULL)
+			return -ENOMEM;
+
+		sl->dccpsl_nr = optlen / sizeof(u32) - 1;
+		if (copy_from_user(sl->dccpsl_list,
+				   optval + sizeof(service),
+				   optlen - sizeof(service)) ||
+		    dccp_list_has_service(sl, DCCP_SERVICE_INVALID_VALUE)) {
+			kfree(sl);
+			return -EFAULT;
+		}
+	}
+
+	lock_sock(sk);
+	dp->dccps_service = service;
+
+	if (dp->dccps_service_list != NULL)
+		kfree(dp->dccps_service_list);
+
+	dp->dccps_service_list = sl;
+	release_sock(sk);
+	return 0;
+}
+
 int dccp_setsockopt(struct sock *sk, int level, int optname,
 		    char __user *optval, int optlen)
 {
@@ -218,8 +262,10 @@ int dccp_setsockopt(struct sock *sk, int level, int optname,
 	if (get_user(val, (int __user *)optval))
 		return -EFAULT;
 
-	lock_sock(sk);
+	if (optname == DCCP_SOCKOPT_SERVICE)
+		return dccp_setsockopt_service(sk, val, optval, optlen);
 
+	lock_sock(sk);
 	dp = dccp_sk(sk);
 	err = 0;
 
@@ -236,6 +282,37 @@ int dccp_setsockopt(struct sock *sk, int level, int optname,
 	return err;
 }
 
+static int dccp_getsockopt_service(struct sock *sk, int len,
+				   u32 __user *optval,
+				   int __user *optlen)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	const struct dccp_service_list *sl;
+	int err = -ENOENT, slen = 0, total_len = sizeof(u32);
+
+	lock_sock(sk);
+	if (dccp_service_not_initialized(sk))
+		goto out;
+
+	if ((sl = dp->dccps_service_list) != NULL) {
+		slen = sl->dccpsl_nr * sizeof(u32);
+		total_len += slen;
+	}
+
+	err = -EINVAL;
+	if (total_len > len)
+		goto out;
+
+	err = 0;
+	if (put_user(total_len, optlen) ||
+	    put_user(dp->dccps_service, optval) ||
+	    (sl != NULL && copy_to_user(optval + 1, sl->dccpsl_list, slen)))
+		err = -EFAULT;
+out:
+	release_sock(sk);
+	return err;
+}
+
 int dccp_getsockopt(struct sock *sk, int level, int optname,
 		    char __user *optval, int __user *optlen)
 {
@@ -248,6 +325,10 @@ int dccp_getsockopt(struct sock *sk, int level, int optname,
 	if (get_user(len, optlen))
 		return -EFAULT;
 
+	if (optname == DCCP_SOCKOPT_SERVICE)
+		return dccp_getsockopt_service(sk, len,
+					       (u32 __user *)optval, optlen);
+
 	len = min_t(unsigned int, len, sizeof(int));
 	if (len < 0)
 		return -EINVAL;