[SCTP] Add SCTP_MAXSEG sockopt.

We'll fragment (if fragmentation not disabled) to the min of maxseg
or PMTU allowance.  

include/net/sctp/sctp.h

@@ -430,12 +430,16 @@ static inline __s32 sctp_jitter(__u32 rto)
 }
 
 /* Break down data chunks at this point.  */
-static inline int sctp_frag_point(int pmtu)
+static inline int sctp_frag_point(const struct sctp_opt *sp, int pmtu)
 {
-	pmtu -= SCTP_IP_OVERHEAD + sizeof(struct sctp_data_chunk);
-	pmtu -= sizeof(struct sctp_sack_chunk);
+	int frag = pmtu;
+	frag -= SCTP_IP_OVERHEAD + sizeof(struct sctp_data_chunk);
+	frag -= sizeof(struct sctp_sack_chunk);
 
-	return pmtu;
+	if (sp->user_frag)
+		frag = min_t(int, frag, sp->user_frag);
+
+	return frag;
 }
 
 /* Walk through a list of TLV parameters.  Don't trust the
@@ -574,21 +578,24 @@ struct sctp6_sock {
 
 #define sctp_sk(__sk) (&((struct sctp_sock *)__sk)->sctp)
 
+/* Is a socket of this style? */
 #define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
-int static inline __sctp_style(struct sock *sk, sctp_socket_type_t style)
+int static inline __sctp_style(const struct sock *sk, sctp_socket_type_t style)
 {
 	return sctp_sk(sk)->type == style;
 }
 
+/* Is the association in this state? */
 #define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
-int static inline __sctp_state(struct sctp_association *asoc, 
+int static inline __sctp_state(const struct sctp_association *asoc, 
 			       sctp_state_t state)
 {
 	return asoc->state == state;
 }
 
+/* Is the socket in this state? */
 #define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
-int static inline __sctp_sstate(struct sock *sk, sctp_sock_state_t state)
+int static inline __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
 {
 	return sk->state == state;
 }

include/net/sctp/structs.h

@@ -292,10 +292,12 @@ struct sctp_opt {
 	struct sctp_rtoinfo rtoinfo;
 	struct sctp_paddrparams paddrparam;
 	struct sctp_event_subscribe subscribe;
+	int user_frag;
 	__u32 autoclose;
 	__u8 nodelay;
 	__u8 disable_fragments;
 	__u8 pd_mode;
+	__u8 v4mapped;
 
 	/* Receive to here while partial delivery is in effect. */
 	struct sk_buff_head pd_lobby;

include/net/sctp/user.h

@@ -110,6 +110,10 @@ enum sctp_optname {
 #define SCTP_GET_LOCAL_ADDRS	SCTP_GET_LOCAL_ADDRS
 	SCTP_NODELAY, 	/* Get/set nodelay option. */
 #define SCTP_NODELAY	SCTP_NODELAY
+	SCTP_I_WANT_MAPPED_V4_ADDR,  /* Turn on/off mapped v4 addresses  */
+#define SCTP_I_WANT_MAPPED_V4_ADDR SCTP_I_WANT_MAPPED_V4_ADDR
+	SCTP_MAXSEG, 	/* Get/set maximum fragment. */
+#define SCTP_MAXSEG 	SCTP_MAXSEG
 };
 
 

net/sctp/associola.c

@@ -391,13 +391,14 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 	struct sctp_opt *sp;
 	unsigned short port;
 
+	sp = sctp_sk(asoc->base.sk);
+
 	/* AF_INET and AF_INET6 share common port field. */
 	port = addr->v4.sin_port;
 
 	/* Set the port if it has not been set yet.  */
-	if (0 == asoc->peer.port) {
+	if (0 == asoc->peer.port)
 		asoc->peer.port = port;
-	}
 
 	/* Check to see if this is a duplicate. */
 	peer = sctp_assoc_lookup_paddr(asoc, addr);
@@ -426,7 +427,7 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 	SCTP_DEBUG_PRINTK("sctp_assoc_add_peer:association %p PMTU set to "
 			  "%d\n", asoc, asoc->pmtu);
 
-	asoc->frag_point = sctp_frag_point(asoc->pmtu);
+	asoc->frag_point = sctp_frag_point(sp, asoc->pmtu);
 
 	/* The asoc->peer.port might not be meaningful yet, but
 	 * initialize the packet structure anyway.
@@ -471,7 +472,7 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
 	/* Initialize the peer's heartbeat interval based on the
 	 * sock configured value.
 	 */
-	sp = sctp_sk(asoc->base.sk);
+
 	peer->hb_interval = sp->paddrparam.spp_hbinterval * HZ;
 
 	/* Attach the remote transport to our asoc.  */
@@ -985,8 +986,9 @@ void sctp_assoc_sync_pmtu(struct sctp_association *asoc)
 	}
 
 	if (pmtu) {
+		struct sctp_opt *sp = sctp_sk(asoc->base.sk);
 		asoc->pmtu = pmtu;
-		asoc->frag_point = sctp_frag_point(pmtu);
+		asoc->frag_point = sctp_frag_point(sp, pmtu);
 	}
 
 	SCTP_DEBUG_PRINTK("%s: asoc:%p, pmtu:%d, frag_point:%d\n",

net/sctp/chunk.c

@@ -158,6 +158,11 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 	max -= sizeof(struct sctp_data_chunk);
 
 	whole = 0;
+
+	/* If user has specified smaller fragmentation, make it so. */
+	if (sctp_sk(asoc->base.sk)->user_frag)
+		max = min_t(int, max, sctp_sk(asoc->base.sk)->user_frag);
+
 	first_len = max;
 
 	/* Encourage Cookie-ECHO bundling. */
@@ -177,7 +182,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
 	over = msg_len % max;
 	offset = 0;
 
-	if (whole && over)
+	if ((whole > 1) || (whole && over))
 		SCTP_INC_STATS_USER(SctpFragUsrMsgs);
 
 	/* Create chunks for all the full sized DATA chunks. */

net/sctp/socket.c

@@ -894,10 +894,10 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
 		SCTP_DEBUG_PRINTK("Just looked up association: "
 				  "%s. \n", asoc->debug_name);
 
-		/* We cannot send a message on a TCP-style SCTP_SS_ESTABLISHED 
+		/* We cannot send a message on a TCP-style SCTP_SS_ESTABLISHED
 		 * socket that has an association in CLOSED state. This can
 		 * happen when an accepted socket has an association that is
-		 * already CLOSED. 
+		 * already CLOSED.
 		 */
 		if (sctp_state(asoc, CLOSED) && sctp_style(sk, TCP)) {
 			err = -EPIPE;
@@ -1082,10 +1082,10 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
 	list_for_each_safe(pos, temp, &datamsg->chunks) {
 		chunk = list_entry(pos, struct sctp_chunk, frag_list);
 		list_del_init(pos);
-		
+
 		/* Do accounting for the write space.  */
 		sctp_set_owner_w(chunk);
-		
+
 		chunk->transport = chunk_tp;
 
 		/* Send it to the lower layers.  */
@@ -1452,7 +1452,6 @@ static int sctp_setsockopt_peer_prim(struct sock *sk, char *optval, int optlen)
 }
 
 /*
- *
  * 7.1.5 SCTP_NODELAY
  *
  * Turn on/off any Nagle-like algorithm.  This means that packets are
@@ -1463,17 +1462,65 @@ static int sctp_setsockopt_peer_prim(struct sock *sk, char *optval, int optlen)
 static int sctp_setsockopt_nodelay(struct sock *sk, char *optval,
 					int optlen)
 {
-	__u8 val;
+	int val;
 
-	if (optlen < sizeof(__u8))
+	if (optlen < sizeof(int))
 		return -EINVAL;
-	if (get_user(val, (__u8 *)optval))
+	if (get_user(val, (int *)optval))
 		return -EFAULT;
 
 	sctp_sk(sk)->nodelay = (val == 0) ? 0 : 1;
 	return 0;
 }
 
+/*
+ * 7.1.16 Set/clear IPv4 mapped addresses (SCTP_I_WANT_MAPPED_V4_ADDR)
+ *
+ * This socket option is a boolean flag which turns on or off mapped V4
+ * addresses.  If this option is turned on and the socket is type
+ * PF_INET6, then IPv4 addresses will be mapped to V6 representation.
+ * If this option is turned off, then no mapping will be done of V4
+ * addresses and a user will receive both PF_INET6 and PF_INET type
+ * addresses on the socket.
+ */
+static int sctp_setsockopt_mappedv4(struct sock *sk, char *optval, int optlen)
+{
+	int val;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+	if (get_user(val, (int *)optval))
+		return -EFAULT;
+	/* FIXME: Put real support here. */
+
+	return -ENOPROTOOPT;
+}
+
+/*
+ * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG)
+ *
+ * This socket option specifies the maximum size to put in any outgoing
+ * SCTP chunk.  If a message is larger than this size it will be
+ * fragmented by SCTP into the specified size.  Note that the underlying
+ * SCTP implementation may fragment into smaller sized chunks when the
+ * PMTU of the underlying association is smaller than the value set by
+ * the user.
+ */
+static int sctp_setsockopt_maxseg(struct sock *sk, char *optval, int optlen)
+{
+	int val;
+
+	if (optlen < sizeof(int))
+		return -EINVAL;
+	if (get_user(val, (int *)optval))
+		return -EFAULT;
+	if ((val < 8) || (val > SCTP_MAX_CHUNK_LEN))
+		return -EINVAL;
+	sctp_sk(sk)->user_frag = val;
+
+	return 0;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -1563,20 +1610,22 @@ SCTP_STATIC int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_INITMSG:
 		retval = sctp_setsockopt_initmsg(sk, optval, optlen);
 		break;
-
 	case SCTP_SET_DEFAULT_SEND_PARAM:
 		retval = sctp_setsockopt_default_send_param(sk, optval,
 							    optlen);
 		break;
-
 	case SCTP_SET_PEER_PRIMARY_ADDR:
 		retval = sctp_setsockopt_peer_prim(sk, optval, optlen);
 		break;
-
 	case SCTP_NODELAY:
 		retval = sctp_setsockopt_nodelay(sk, optval, optlen);
 		break;
-
+	case SCTP_I_WANT_MAPPED_V4_ADDR:
+		retval = sctp_setsockopt_mappedv4(sk, optval, optlen);
+		break;
+	case SCTP_MAXSEG:
+		retval = sctp_setsockopt_maxseg(sk, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
@@ -1703,7 +1752,7 @@ SCTP_STATIC int sctp_connect(struct sock *sk, struct sockaddr *uaddr,
 	/* Initialize sk's dport and daddr for getpeername() */
 	inet_sk(sk)->dport = htons(asoc->peer.port);
 	af = sctp_get_af_specific(to.sa.sa_family);
-	af->to_sk_daddr(&to, sk); 
+	af->to_sk_daddr(&to, sk);
 
 	timeo = sock_sndtimeo(sk, sk->socket->file->f_flags & O_NONBLOCK);
 	err = sctp_wait_for_connect(asoc, &timeo);
@@ -1861,12 +1910,19 @@ SCTP_STATIC int sctp_init_sock(struct sock *sk)
 	/* Turn on/off any Nagle-like algorithm.  */
 	sp->nodelay           = 1;
 
+	/* Enable by default. */
+	sp->v4mapped          = 1;
+
 	/* Auto-close idle associations after the configured
 	 * number of seconds.  A value of 0 disables this
 	 * feature.  Configure through the SCTP_AUTOCLOSE socket option,
 	 * for UDP-style sockets only.
 	 */
 	sp->autoclose         = 0;
+
+	/* User specified fragmentation limit. */
+	sp->user_frag         = 0;
+
 	sp->pf = sctp_get_pf_specific(sk->family);
 
 	/* Control variables for partial data delivery. */
@@ -1978,6 +2034,10 @@ static int sctp_getsockopt_sctp_status(struct sock *sk, int len, char *optval,
 	status.sstat_penddata = asoc->peer.tsn_map.pending_data;
 	status.sstat_instrms = asoc->c.sinit_max_instreams;
 	status.sstat_outstrms = asoc->c.sinit_num_ostreams;
+	/* Just in time frag_point update. */
+	if (sctp_sk(sk)->user_frag)
+		asoc->frag_point
+			= min_t(int, asoc->frag_point, sctp_sk(sk)->user_frag);
 	status.sstat_fragmentation_point = asoc->frag_point;
 	status.sstat_primary.spinfo_assoc_id = sctp_assoc2id(transport->asoc);
 	memcpy(&status.sstat_primary.spinfo_address,
@@ -2417,14 +2477,14 @@ static int sctp_getsockopt_default_send_param(struct sock *sk,
  */
 
 static int sctp_getsockopt_nodelay(struct sock *sk, int len,
-					char *optval, int *optlen)
+				   char *optval, int *optlen)
 {
-	__u8 val;
+	int val;
 
-	if (len < sizeof(__u8))
+	if (len < sizeof(int))
 		return -EINVAL;
 
-	len = sizeof(__u8);
+	len = sizeof(int);
 	val = (sctp_sk(sk)->nodelay == 1);
 	if (put_user(len, optlen))
 		return -EFAULT;
@@ -2432,6 +2492,62 @@ static int sctp_getsockopt_nodelay(struct sock *sk, int len,
 		return -EFAULT;
 	return 0;
 }
+/*
+ * 7.1.16 Set/clear IPv4 mapped addresses (SCTP_I_WANT_MAPPED_V4_ADDR)
+ *
+ * This socket option is a boolean flag which turns on or off mapped V4
+ * addresses.  If this option is turned on and the socket is type
+ * PF_INET6, then IPv4 addresses will be mapped to V6 representation.
+ * If this option is turned off, then no mapping will be done of V4
+ * addresses and a user will receive both PF_INET6 and PF_INET type
+ * addresses on the socket.
+ */
+static int sctp_getsockopt_mappedv4(struct sock *sk, int len,
+				    char *optval, int *optlen)
+{
+	int val;
+	if (len < sizeof(int))
+		return -EINVAL;
+
+	len = sizeof(int);
+	/* FIXME: Until we have support, return disabled. */
+	val = 0;
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG)
+ *
+ * This socket option specifies the maximum size to put in any outgoing
+ * SCTP chunk.  If a message is larger than this size it will be
+ * fragmented by SCTP into the specified size.  Note that the underlying
+ * SCTP implementation may fragment into smaller sized chunks when the
+ * PMTU of the underlying association is smaller than the value set by
+ * the user.
+ */
+static int sctp_getsockopt_maxseg(struct sock *sk, int len,
+				  char *optval, int *optlen)
+{
+	int val;
+
+	if (len < sizeof(int))
+		return -EINVAL;
+
+	len = sizeof(int);
+
+	val = sctp_sk(sk)->user_frag;
+	if (put_user(len, optlen))
+		return -EFAULT;
+	if (copy_to_user(optval, &val, len))
+		return -EFAULT;
+
+	return 0;
+}
 
 SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
 				char *optval, int *optlen)
@@ -2509,6 +2625,12 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
 	case SCTP_NODELAY:
 		retval = sctp_getsockopt_nodelay(sk, len, optval, optlen);
 		break;
+	case SCTP_I_WANT_MAPPED_V4_ADDR:
+		retval = sctp_getsockopt_mappedv4(sk, len, optval, optlen);
+		break;
+	case SCTP_MAXSEG:
+		retval = sctp_getsockopt_maxseg(sk, len, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;