1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* lib/krb5/os/write_msg.c - convenience sendauh/recvauth functions */
3 /*
4 * Copyright 1991, 2009 by the Massachusetts Institute of Technology.
5 * All Rights Reserved.
6 *
7 * Export of this software from the United States of America may
8 * require a specific license from the United States Government.
9 * It is the responsibility of any person or organization contemplating
10 * export to obtain such a license before exporting.
11 *
12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
13 * distribute this software and its documentation for any purpose and
14 * without fee is hereby granted, provided that the above copyright
15 * notice appear in all copies and that both that copyright notice and
16 * this permission notice appear in supporting documentation, and that
17 * the name of M.I.T. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission. Furthermore if you modify this software you must label
20 * your software as modified software and not distribute it in such a
21 * fashion that it might be confused with the original M.I.T. software.
22 * M.I.T. makes no representations about the suitability of
23 * this software for any purpose. It is provided "as is" without express
24 * or implied warranty.
25 */
26
27 #include "k5-int.h"
28 #include <errno.h>
29 #include "os-proto.h"
30
31 /*
32 * Try to write a series of messages with as few write(v) system calls
33 * as possible, to avoid Nagle/DelayedAck problems. Cheating here a
34 * little -- I know the only cases we have at the moment will send one
35 * or two messages in a call. Sending more will work, but not as
36 * efficiently.
37 */
38 krb5_error_code
k5_write_messages(krb5_context context,krb5_pointer fdp,krb5_data * outbuf,int nbufs)39 k5_write_messages(krb5_context context, krb5_pointer fdp, krb5_data *outbuf,
40 int nbufs)
41 {
42 int fd = *( (int *) fdp);
43
44 while (nbufs) {
45 int nbufs1;
46 sg_buf sg[4];
47 krb5_int32 len[2];
48
49 if (nbufs > 1)
50 nbufs1 = 2;
51 else
52 nbufs1 = 1;
53 len[0] = htonl(outbuf[0].length);
54 SG_SET(&sg[0], &len[0], 4);
55 SG_SET(&sg[1], outbuf[0].length ? outbuf[0].data : NULL,
56 outbuf[0].length);
57 if (nbufs1 == 2) {
58 len[1] = htonl(outbuf[1].length);
59 SG_SET(&sg[2], &len[1], 4);
60 SG_SET(&sg[3], outbuf[1].length ? outbuf[1].data : NULL,
61 outbuf[1].length);
62 }
63 if (krb5int_net_writev(context, fd, sg, nbufs1 * 2) < 0) {
64 return errno;
65 }
66 outbuf += nbufs1;
67 nbufs -= nbufs1;
68 }
69 return(0);
70 }
71
72 krb5_error_code
krb5_write_message(krb5_context context,krb5_pointer fdp,krb5_data * outbuf)73 krb5_write_message(krb5_context context, krb5_pointer fdp, krb5_data *outbuf)
74 {
75 return k5_write_messages(context, fdp, outbuf, 1);
76 }
77