/* 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)