1 /* SCTP kernel Implementation: User API extensions.
2 *
3 * sctp_recvmsg.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 International Business Machines, Corp.
17 *
18 * Written or modified by:
19 * Ryan Layer <rmlayer@us.ibm.com>
20 *
21 * An implementation may provide a library function (or possibly system
22 * call) to assist the user with the advanced features of SCTP. Note
23 * that in order for the sctp_sndrcvinfo structure to be filled in by
24 * sctp_recvmsg() the caller must enable the sctp_data_io_events with
25 * the SCTP_EVENTS option.
26 *
27 * sctp_recvmsg(). Its syntax is,
28 *
29 * int sctp_recvmsg(int s,
30 * void *msg,
31 * size_t len,
32 * struct sockaddr *from,
33 * socklen_t *fromlen,
34 * struct sctp_sndrcvinfo *sinfo,
35 * int *msg_flags)
36 *
37 *
38 * s - is the socket descriptor
39 * msg - is a message buffer to be filled.
40 * len - is the length of the message buffer.
41 * from - is a pointer to a address to be filled with
42 * the sender of this messages address.
43 * fromlen - is the from length.
44 * sinfo - A pointer to a sctp_sndrcvinfo structure
45 * to be filled upon receipt of the message.
46 * msg_flags - A pointer to a integer to be filled with
47 * any message flags (e.g. MSG_NOTIFICATION).
48 */
49
50 #include <string.h>
51 #include <errno.h>
52 #include <sys/socket.h> /* struct sockaddr_storage, setsockopt() */
53 #include <netinet/sctp.h>
54
sctp_recvmsg(int s,void * msg,size_t len,struct sockaddr * from,socklen_t * fromlen,struct sctp_sndrcvinfo * sinfo,int * msg_flags)55 int sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
56 socklen_t *fromlen, struct sctp_sndrcvinfo *sinfo,
57 int *msg_flags)
58 {
59 int error;
60 struct iovec iov;
61 struct msghdr inmsg;
62 char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
63 struct cmsghdr *cmsg = NULL;
64
65 memset(&inmsg, 0, sizeof (inmsg));
66
67 iov.iov_base = msg;
68 iov.iov_len = len;
69
70 inmsg.msg_name = from;
71 inmsg.msg_namelen = fromlen ? *fromlen : 0;
72 inmsg.msg_iov = &iov;
73 inmsg.msg_iovlen = 1;
74 inmsg.msg_control = incmsg;
75 inmsg.msg_controllen = sizeof(incmsg);
76
77 error = recvmsg(s, &inmsg, msg_flags ? *msg_flags : 0);
78 if (error < 0)
79 return error;
80
81 if (fromlen)
82 *fromlen = inmsg.msg_namelen;
83 if (msg_flags)
84 *msg_flags = inmsg.msg_flags;
85
86 if (!sinfo)
87 return error;
88
89 for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL;
90 cmsg = CMSG_NXTHDR(&inmsg, cmsg)){
91 if ((IPPROTO_SCTP == cmsg->cmsg_level) &&
92 (SCTP_SNDRCV == cmsg->cmsg_type))
93 break;
94 }
95
96 /* Copy sinfo. */
97 if (cmsg)
98 memcpy(sinfo, CMSG_DATA(cmsg), sizeof(struct sctp_sndrcvinfo));
99
100 return (error);
101 }
102