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- /* Return point to next ancillary data entry in message header.
- Copyright (C) 1997, 1998, 2001 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
- <http://www.gnu.org/licenses/>. */
- #include <features.h>
- #include <stddef.h>
- /* Prevent math.h from defining a colliding inline */
- #undef __USE_EXTERN_INLINES
- #include <sys/socket.h>
- struct cmsghdr *
- __cmsg_nxthdr (struct msghdr *mhdr, struct cmsghdr *cmsg)
- {
- if ((size_t) cmsg->cmsg_len < sizeof (struct cmsghdr))
- /* The kernel header does this so there may be a reason. */
- return NULL;
- cmsg = (struct cmsghdr *) ((unsigned char *) cmsg
- + CMSG_ALIGN (cmsg->cmsg_len));
- if ((unsigned char *) (cmsg + 1) > ((unsigned char *) mhdr->msg_control
- + mhdr->msg_controllen)
- || ((unsigned char *) cmsg + CMSG_ALIGN (cmsg->cmsg_len)
- > ((unsigned char *) mhdr->msg_control + mhdr->msg_controllen)))
- /* No more entries. */
- return NULL;
- return cmsg;
- }
- libc_hidden_def(__cmsg_nxthdr)
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