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112 lines
3.4 KiB
C
112 lines
3.4 KiB
C
/* Socket timestamp conversion routines.
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Copyright (C) 2021-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <bits/timesize.h>
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#if __TIMESIZE != 64
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# include <stdint.h>
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# include <string.h>
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# include <sys/socket.h>
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# include <socket-constants-time64.h>
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# include <libc-diag.h>
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/* It converts the first SO_TIMESTAMP or SO_TIMESTAMPNS with 32-bit time and
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appends it to the control buffer. The 32-bit time field is kept as-is.
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Calls with __TIMESIZE=32 will see the converted 64-bit time control
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messages as spurious control message of unknown type.
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Calls with __TIMESIZE=64 running on pre-time64 kernels will see the
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original message as a spurious control ones of unknown typ while running
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on kernel with native 64-bit time support will only see the time64 version
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of the control message. */
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void
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__convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)
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{
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if (msg->msg_control == NULL || msg->msg_controllen == 0)
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return;
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/* The returned control message format for SO_TIMESTAMP_NEW is a
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'struct __kernel_sock_timeval' while for SO_TIMESTAMPNS_NEW is a
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'struct __kernel_timespec'. In either case it is two uint64_t
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members. */
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/* GCC 6 issues an warning that tvts[0]/tvts[1] maybe be used uninitialized,
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however it would be used if type is set to a value different than 0
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(done by either COMPAT_SO_TIMESTAMP_OLD or COMPAT_SO_TIMESTAMPNS_OLD)
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which will fallthrough to 'common' label. */
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DIAG_PUSH_NEEDS_COMMENT;
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DIAG_IGNORE_NEEDS_COMMENT (6, "-Wmaybe-uninitialized");
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int64_t tvts[2];
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DIAG_POP_NEEDS_COMMENT;
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int32_t tmp[2];
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struct cmsghdr *cmsg, *last = NULL;
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int type = 0;
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for (cmsg = CMSG_FIRSTHDR (msg);
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cmsg != NULL;
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cmsg = CMSG_NXTHDR (msg, cmsg))
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{
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last = cmsg;
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if (cmsg->cmsg_level != SOL_SOCKET)
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continue;
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switch (cmsg->cmsg_type)
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{
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case COMPAT_SO_TIMESTAMP_OLD:
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if (type != 0)
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break;
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type = COMPAT_SO_TIMESTAMP_NEW;
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goto common;
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case COMPAT_SO_TIMESTAMPNS_OLD:
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type = COMPAT_SO_TIMESTAMPNS_NEW;
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/* fallthrough */
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common:
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memcpy (tmp, CMSG_DATA (cmsg), sizeof (tmp));
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tvts[0] = tmp[0];
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tvts[1] = tmp[1];
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break;
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}
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}
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if (type == 0)
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return;
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if (CMSG_SPACE (sizeof tvts) > msgsize - msg->msg_controllen)
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{
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msg->msg_flags |= MSG_CTRUNC;
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return;
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}
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/* Zero memory for the new cmsghdr, so reading cmsg_len field
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by CMSG_NXTHDR does not trigger UB. */
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memset (msg->msg_control + msg->msg_controllen, 0,
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CMSG_SPACE (sizeof tvts));
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msg->msg_controllen += CMSG_SPACE (sizeof tvts);
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cmsg = CMSG_NXTHDR (msg, last);
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cmsg->cmsg_level = SOL_SOCKET;
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cmsg->cmsg_type = type;
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cmsg->cmsg_len = CMSG_LEN (sizeof tvts);
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memcpy (CMSG_DATA (cmsg), tvts, sizeof tvts);
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}
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#endif
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