diff options
Diffstat (limited to 'libc/inet/if_index.c')
| -rw-r--r-- | libc/inet/if_index.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/libc/inet/if_index.c b/libc/inet/if_index.c new file mode 100644 index 000000000..5837faa65 --- /dev/null +++ b/libc/inet/if_index.c @@ -0,0 +1,218 @@ +/* Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005 + 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. + + Reworked Dec 2002 by Erik Andersen <andersen@codepoet.org> + */ + +#define strndup __strndup + +#define __FORCE_GLIBC +#include <features.h> +#define __USE_GNU +#include <string.h> +#include <alloca.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <net/if.h> +#include <sys/socket.h> +#include <sys/ioctl.h> +#include <libc-internal.h> + +extern int __opensock(void) attribute_hidden; + +unsigned int +if_nametoindex(const char* ifname) +{ +#ifndef SIOCGIFINDEX + __set_errno (ENOSYS); + return 0; +#else + struct ifreq ifr; + int fd = __opensock(); + + if (fd < 0) + return 0; + + __strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name)); + if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0) + { + int saved_errno = errno; + __close(fd); + if (saved_errno == EINVAL) + __set_errno(ENOSYS); + return 0; + } + + __close(fd); + return ifr.ifr_ifindex; +#endif +} + +void +if_freenameindex (struct if_nameindex *ifn) +{ + struct if_nameindex *ptr = ifn; + while (ptr->if_name || ptr->if_index) + { + free (ptr->if_name); + ++ptr; + } + free (ifn); +} + +struct if_nameindex * +if_nameindex (void) +{ +#ifndef SIOCGIFINDEX + __set_errno (ENOSYS); + return NULL; +#else + int fd = __opensock (); + struct ifconf ifc; + unsigned int nifs, i; + int rq_len; + struct if_nameindex *idx = NULL; +# define RQ_IFS 4 + + if (fd < 0) + return NULL; + + ifc.ifc_buf = NULL; + + /* Guess on the correct buffer size... */ + rq_len = RQ_IFS * sizeof (struct ifreq); + + /* Read all the interfaces out of the kernel. */ + ifc.ifc_buf = alloca (rq_len); + ifc.ifc_len = rq_len; + while (1) + { + if (__ioctl (fd, SIOCGIFCONF, &ifc) < 0) + { + __close (fd); + return NULL; + } + if (ifc.ifc_len < rq_len) + break; + + ifc.ifc_buf = extend_alloca (ifc.ifc_buf, rq_len, 2 * rq_len); + ifc.ifc_len = rq_len; + } + + nifs = ifc.ifc_len / sizeof(struct ifreq); + + idx = malloc ((nifs + 1) * sizeof (struct if_nameindex)); + if (idx == NULL) + { + __close(fd); + __set_errno(ENOBUFS); + return NULL; + } + + for (i = 0; i < nifs; ++i) + { + struct ifreq *ifr = &ifc.ifc_req[i]; + idx[i].if_name = __strdup (ifr->ifr_name); + if (idx[i].if_name == NULL + || __ioctl (fd, SIOCGIFINDEX, ifr) < 0) + { + int saved_errno = errno; + unsigned int j; + + for (j = 0; j < i; ++j) + free (idx[j].if_name); + free(idx); + __close(fd); + if (saved_errno == EINVAL) + saved_errno = ENOSYS; + else if (saved_errno == ENOMEM) + saved_errno = ENOBUFS; + __set_errno (saved_errno); + return NULL; + } + idx[i].if_index = ifr->ifr_ifindex; + } + + idx[i].if_index = 0; + idx[i].if_name = NULL; + + __close(fd); + return idx; +#endif +} + +char * +if_indextoname (unsigned int ifindex, char *ifname) +{ +#if !defined SIOCGIFINDEX + __set_errno (ENOSYS); + return NULL; +#else +# ifdef SIOCGIFNAME + /* Use ioctl to avoid searching the list. */ + struct ifreq ifr; + int fd; + + fd = __opensock (); + + if (fd < 0) + return NULL; + + ifr.ifr_ifindex = ifindex; + if (__ioctl (fd, SIOCGIFNAME, &ifr) < 0) + { + int serrno = errno; + __close (fd); + if (serrno == ENODEV) + /* POSIX requires ENXIO. */ + serrno = ENXIO; + __set_errno (serrno); + return NULL; + } + __close (fd); + + return __strncpy (ifname, ifr.ifr_name, IFNAMSIZ); +# else + struct if_nameindex *idx; + struct if_nameindex *p; + char *result = NULL; + + idx = if_nameindex(); + + if (idx != NULL) + { + for (p = idx; p->if_index || p->if_name; ++p) + if (p->if_index == ifindex) + { + result = __strncpy (ifname, p->if_name, IFNAMSIZ); + break; + } + + if_freenameindex (idx); + + if (result == NULL) + __set_errno (ENXIO); + } + return result; +# endif +#endif +} + |