1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Some common code for MSG_ZEROCOPY logic
3 *
4 * Copyright (C) 2023 SberDevices.
5 *
6 * Author: Arseniy Krasnov <avkrasnov@salutedevices.com>
7 */
8
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <sys/types.h>
12 #include <sys/socket.h>
13 #include <linux/errqueue.h>
14
15 #include "msg_zerocopy_common.h"
16
17 void enable_so_zerocopy(int fd)
18 {
19 int val = 1;
20
21 if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val))) {
22 perror("setsockopt");
23 exit(EXIT_FAILURE);
24 }
25 }
26
27 void vsock_recv_completion(int fd, const bool *zerocopied)
28 {
29 struct sock_extended_err *serr;
30 struct msghdr msg = { 0 };
31 char cmsg_data[128];
32 struct cmsghdr *cm;
33 ssize_t res;
34
35 msg.msg_control = cmsg_data;
36 msg.msg_controllen = sizeof(cmsg_data);
37
38 res = recvmsg(fd, &msg, MSG_ERRQUEUE);
39 if (res) {
40 fprintf(stderr, "failed to read error queue: %zi\n", res);
41 exit(EXIT_FAILURE);
42 }
43
44 cm = CMSG_FIRSTHDR(&msg);
45 if (!cm) {
46 fprintf(stderr, "cmsg: no cmsg\n");
47 exit(EXIT_FAILURE);
48 }
49
50 if (cm->cmsg_level != SOL_VSOCK) {
51 fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
52 exit(EXIT_FAILURE);
53 }
54
55 if (cm->cmsg_type != VSOCK_RECVERR) {
56 fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
57 exit(EXIT_FAILURE);
58 }
59
60 serr = (void *)CMSG_DATA(cm);
61 if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
62 fprintf(stderr, "serr: wrong origin: %u\n", serr->ee_origin);
63 exit(EXIT_FAILURE);
64 }
65
66 if (serr->ee_errno) {
67 fprintf(stderr, "serr: wrong error code: %u\n", serr->ee_errno);
68 exit(EXIT_FAILURE);
69 }
70
71 /* This flag is used for tests, to check that transmission was
72 * performed as expected: zerocopy or fallback to copy. If NULL
73 * - don't care.
74 */
75 if (!zerocopied)
76 return;
77
78 if (*zerocopied && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
79 fprintf(stderr, "serr: was copy instead of zerocopy\n");
80 exit(EXIT_FAILURE);
81 }
82
83 if (!*zerocopied && !(serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
84 fprintf(stderr, "serr: was zerocopy instead of copy\n");
85 exit(EXIT_FAILURE);
86 }
87 }
88
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