1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009-2010 The FreeBSD Foundation
5 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>
6 * All rights reserved.
7 *
8 * This software was developed by Pawel Jakub Dawidek under sponsorship from
9 * the FreeBSD Foundation.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 #include <sys/types.h>
35 #include <sys/socket.h>
36
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <stdbool.h>
40 #include <stdlib.h>
41 #include <strings.h>
42 #include <unistd.h>
43
44 #include "pjdlog.h"
45 #include "proto_impl.h"
46
47 /* Maximum size of packet we want to use when sending data. */
48 #ifndef MAX_SEND_SIZE
49 #define MAX_SEND_SIZE 32768
50 #endif
51
52 static bool
blocking_socket(int sock)53 blocking_socket(int sock)
54 {
55 int flags;
56
57 flags = fcntl(sock, F_GETFL);
58 PJDLOG_ASSERT(flags >= 0);
59 return ((flags & O_NONBLOCK) == 0);
60 }
61
62 static int
proto_descriptor_send(int sock,int fd)63 proto_descriptor_send(int sock, int fd)
64 {
65 unsigned char ctrl[CMSG_SPACE(sizeof(fd))];
66 struct msghdr msg;
67 struct cmsghdr *cmsg;
68
69 PJDLOG_ASSERT(sock >= 0);
70 PJDLOG_ASSERT(fd >= 0);
71
72 bzero(&msg, sizeof(msg));
73 bzero(&ctrl, sizeof(ctrl));
74
75 msg.msg_iov = NULL;
76 msg.msg_iovlen = 0;
77 msg.msg_control = ctrl;
78 msg.msg_controllen = sizeof(ctrl);
79
80 cmsg = CMSG_FIRSTHDR(&msg);
81 cmsg->cmsg_level = SOL_SOCKET;
82 cmsg->cmsg_type = SCM_RIGHTS;
83 cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
84 bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd));
85
86 if (sendmsg(sock, &msg, 0) == -1)
87 return (errno);
88
89 return (0);
90 }
91
92 int
proto_common_send(int sock,const unsigned char * data,size_t size,int fd)93 proto_common_send(int sock, const unsigned char *data, size_t size, int fd)
94 {
95 ssize_t done;
96 size_t sendsize;
97 int errcount = 0;
98
99 PJDLOG_ASSERT(sock >= 0);
100
101 if (data == NULL) {
102 /* The caller is just trying to decide about direction. */
103
104 PJDLOG_ASSERT(size == 0);
105
106 if (shutdown(sock, SHUT_RD) == -1)
107 return (errno);
108 return (0);
109 }
110
111 PJDLOG_ASSERT(data != NULL);
112 PJDLOG_ASSERT(size > 0);
113
114 do {
115 sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE;
116 done = send(sock, data, sendsize, MSG_NOSIGNAL);
117 if (done == 0) {
118 return (ENOTCONN);
119 } else if (done == -1) {
120 if (errno == EINTR)
121 continue;
122 if (errno == ENOBUFS) {
123 /*
124 * If there are no buffers we retry.
125 * After each try we increase delay before the
126 * next one and we give up after fifteen times.
127 * This gives 11s of total wait time.
128 */
129 if (errcount == 15) {
130 pjdlog_warning("Getting ENOBUFS errors for 11s on send(), giving up.");
131 } else {
132 if (errcount == 0)
133 pjdlog_warning("Got ENOBUFS error on send(), retrying for a bit.");
134 errcount++;
135 usleep(100000 * errcount);
136 continue;
137 }
138 }
139 /*
140 * If this is blocking socket and we got EAGAIN, this
141 * means the request timed out. Translate errno to
142 * ETIMEDOUT, to give administrator a hint to
143 * eventually increase timeout.
144 */
145 if (errno == EAGAIN && blocking_socket(sock))
146 errno = ETIMEDOUT;
147 return (errno);
148 }
149 data += done;
150 size -= done;
151 } while (size > 0);
152 if (errcount > 0) {
153 pjdlog_info("Data sent successfully after %d ENOBUFS error%s.",
154 errcount, errcount == 1 ? "" : "s");
155 }
156
157 if (fd == -1)
158 return (0);
159 return (proto_descriptor_send(sock, fd));
160 }
161
162 static int
proto_descriptor_recv(int sock,int * fdp)163 proto_descriptor_recv(int sock, int *fdp)
164 {
165 unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))];
166 struct msghdr msg;
167 struct cmsghdr *cmsg;
168
169 PJDLOG_ASSERT(sock >= 0);
170 PJDLOG_ASSERT(fdp != NULL);
171
172 bzero(&msg, sizeof(msg));
173 bzero(&ctrl, sizeof(ctrl));
174
175 msg.msg_iov = NULL;
176 msg.msg_iovlen = 0;
177 msg.msg_control = ctrl;
178 msg.msg_controllen = sizeof(ctrl);
179
180 if (recvmsg(sock, &msg, 0) == -1)
181 return (errno);
182
183 cmsg = CMSG_FIRSTHDR(&msg);
184 if (cmsg == NULL || cmsg->cmsg_level != SOL_SOCKET ||
185 cmsg->cmsg_type != SCM_RIGHTS) {
186 return (EINVAL);
187 }
188 bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp));
189
190 return (0);
191 }
192
193 int
proto_common_recv(int sock,unsigned char * data,size_t size,int * fdp)194 proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp)
195 {
196 ssize_t done;
197
198 PJDLOG_ASSERT(sock >= 0);
199
200 if (data == NULL) {
201 /* The caller is just trying to decide about direction. */
202
203 PJDLOG_ASSERT(size == 0);
204
205 if (shutdown(sock, SHUT_WR) == -1)
206 return (errno);
207 return (0);
208 }
209
210 PJDLOG_ASSERT(data != NULL);
211 PJDLOG_ASSERT(size > 0);
212
213 do {
214 done = recv(sock, data, size, MSG_WAITALL);
215 } while (done == -1 && errno == EINTR);
216 if (done == 0) {
217 return (ENOTCONN);
218 } else if (done == -1) {
219 /*
220 * If this is blocking socket and we got EAGAIN, this
221 * means the request timed out. Translate errno to
222 * ETIMEDOUT, to give administrator a hint to
223 * eventually increase timeout.
224 */
225 if (errno == EAGAIN && blocking_socket(sock))
226 errno = ETIMEDOUT;
227 return (errno);
228 }
229 if (fdp == NULL)
230 return (0);
231 return (proto_descriptor_recv(sock, fdp));
232 }
233