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1 /* SCTP kernel Implementation: User API extensions.
2  *
3  * sendmsg.c
4  *
5  * Distributed under the terms of the LGPL v2.1 as described in
6  *    http://www.gnu.org/copyleft/lesser.txt
7  *
8  * This file is part of the user library that offers support for the
9  * SCTP kernel Implementation. The main purpose of this
10  * code is to provide the SCTP Socket API mappings for user
11  * application to interface with the SCTP in kernel.
12  *
13  * This implementation is based on the Socket API Extensions for SCTP
14  * defined in <draft-ietf-tsvwg-sctpsocket-10.txt>
15  *
16  * Copyright (c) 2003 Intel Corp.
17  *
18  * Written or modified by:
19  *  Ardelle Fan     <ardelle.fan@intel.com>
20  */
21 
22 #include <string.h>
23 #include <sys/socket.h>   /* struct sockaddr_storage, setsockopt() */
24 #include <netinet/sctp.h>
25 
26 /* This library function assists the user with the advanced features
27  * of SCTP.  This is a new SCTP API described in the section 8.7 of the
28  * Sockets API Extensions for SCTP. This is implemented using the
29  * sendmsg() interface.
30  */
31 int
sctp_sendmsg(int s,const void * msg,size_t len,struct sockaddr * to,socklen_t tolen,uint32_t ppid,uint32_t flags,uint16_t stream_no,uint32_t timetolive,uint32_t context)32 sctp_sendmsg(int s, const void *msg, size_t len, struct sockaddr *to,
33 	     socklen_t tolen, uint32_t ppid, uint32_t flags,
34 	     uint16_t stream_no, uint32_t timetolive, uint32_t context)
35 {
36 	struct msghdr outmsg;
37 	struct iovec iov;
38 	char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
39 	struct cmsghdr *cmsg;
40 	struct sctp_sndrcvinfo *sinfo;
41 
42 	outmsg.msg_name = to;
43 	outmsg.msg_namelen = tolen;
44 	outmsg.msg_iov = &iov;
45 	iov.iov_base = (void *)msg;
46 	iov.iov_len = len;
47 	outmsg.msg_iovlen = 1;
48 
49 	outmsg.msg_control = outcmsg;
50 	outmsg.msg_controllen = sizeof(outcmsg);
51 	outmsg.msg_flags = 0;
52 
53 	cmsg = CMSG_FIRSTHDR(&outmsg);
54 	cmsg->cmsg_level = IPPROTO_SCTP;
55 	cmsg->cmsg_type = SCTP_SNDRCV;
56 	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
57 
58 	outmsg.msg_controllen = cmsg->cmsg_len;
59 	sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
60 	memset(sinfo, 0, sizeof(struct sctp_sndrcvinfo));
61 	sinfo->sinfo_ppid = ppid;
62 	sinfo->sinfo_flags = flags;
63 	sinfo->sinfo_stream = stream_no;
64 	sinfo->sinfo_timetolive = timetolive;
65 	sinfo->sinfo_context = context;
66 
67 	return sendmsg(s, &outmsg, 0);
68 }
69 
70 /* This library function assist the user with sending a message without
71  * dealing directly with the CMSG header.
72  */
73 int
sctp_send(int s,const void * msg,size_t len,const struct sctp_sndrcvinfo * sinfo,int flags)74 sctp_send(int s, const void *msg, size_t len,
75           const struct sctp_sndrcvinfo *sinfo, int flags)
76 {
77 	struct msghdr outmsg;
78 	struct iovec iov;
79 	char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
80 
81 	outmsg.msg_name = NULL;
82 	outmsg.msg_namelen = 0;
83 	outmsg.msg_iov = &iov;
84 	iov.iov_base = (void *)msg;
85 	iov.iov_len = len;
86 	outmsg.msg_iovlen = 1;
87 	outmsg.msg_controllen = 0;
88 
89 	if (sinfo) {
90 		struct cmsghdr *cmsg;
91 
92 		outmsg.msg_control = outcmsg;
93 		outmsg.msg_controllen = sizeof(outcmsg);
94 		outmsg.msg_flags = 0;
95 
96 		cmsg = CMSG_FIRSTHDR(&outmsg);
97 		cmsg->cmsg_level = IPPROTO_SCTP;
98 		cmsg->cmsg_type = SCTP_SNDRCV;
99 		cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
100 
101 		outmsg.msg_controllen = cmsg->cmsg_len;
102 		memcpy(CMSG_DATA(cmsg), sinfo, sizeof(struct sctp_sndrcvinfo));
103 	}
104 
105 	return sendmsg(s, &outmsg, flags);
106 }
107