tools/testing/vsock/msg_zerocopy_common.c

   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 vsock_recv_completion(int fd, const bool *zerocopied)
  18 {
  19         struct sock_extended_err *serr;
  20         struct msghdr msg = { 0 };
  21         char cmsg_data[128];
  22         struct cmsghdr *cm;
  23         ssize_t res;
  24
  25         msg.msg_control = cmsg_data;
  26         msg.msg_controllen = sizeof(cmsg_data);
  27
  28         res = recvmsg(fd, &msg, MSG_ERRQUEUE);
  29         if (res) {
  30                 fprintf(stderr, "failed to read error queue: %zi\n", res);
  31                 exit(EXIT_FAILURE);
  32         }
  33
  34         cm = CMSG_FIRSTHDR(&msg);
  35         if (!cm) {
  36                 fprintf(stderr, "cmsg: no cmsg\n");
  37                 exit(EXIT_FAILURE);
  38         }
  39
  40         if (cm->cmsg_level != SOL_VSOCK) {
  41                 fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
  42                 exit(EXIT_FAILURE);
  43         }
  44
  45         if (cm->cmsg_type != VSOCK_RECVERR) {
  46                 fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
  47                 exit(EXIT_FAILURE);
  48         }
  49
  50         serr = (void *)CMSG_DATA(cm);
  51         if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
  52                 fprintf(stderr, "serr: wrong origin: %u\n", serr->ee_origin);
  53                 exit(EXIT_FAILURE);
  54         }
  55
  56         if (serr->ee_errno) {
  57                 fprintf(stderr, "serr: wrong error code: %u\n", serr->ee_errno);
  58                 exit(EXIT_FAILURE);
  59         }
  60
  61         /* This flag is used for tests, to check that transmission was
  62          * performed as expected: zerocopy or fallback to copy. If NULL
  63          * - don't care.
  64          */
  65         if (!zerocopied)
  66                 return;
  67
  68         if (*zerocopied && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
  69                 fprintf(stderr, "serr: was copy instead of zerocopy\n");
  70                 exit(EXIT_FAILURE);
  71         }
  72
  73         if (!*zerocopied && !(serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED)) {
  74                 fprintf(stderr, "serr: was zerocopy instead of copy\n");
  75                 exit(EXIT_FAILURE);
  76         }
  77 }