diff options
Diffstat (limited to 'resolv')
| -rw-r--r-- | resolv/Makefile | 2 | ||||
| -rw-r--r-- | resolv/Versions | 2 | ||||
| -rw-r--r-- | resolv/nss_dns/dns-canon.c | 137 |
3 files changed, 139 insertions, 2 deletions
diff --git a/resolv/Makefile b/resolv/Makefile index a91e8a6f44..f6230da8fb 100644 --- a/resolv/Makefile +++ b/resolv/Makefile @@ -57,7 +57,7 @@ libanl-routines := gai_cancel gai_error gai_misc gai_notify gai_suspend \ subdir-dirs = nss_dns vpath %.c nss_dns -libnss_dns-routines := dns-host dns-network +libnss_dns-routines := dns-host dns-network dns-canon ifneq ($(build-static-nss),yes) libnss_dns-inhibit-o = $(filter-out .os,$(object-suffixes)) endif diff --git a/resolv/Versions b/resolv/Versions index a809508aa0..0e4fea5e19 100644 --- a/resolv/Versions +++ b/resolv/Versions @@ -86,7 +86,7 @@ libnss_dns { GLIBC_PRIVATE { _nss_dns_gethostbyaddr_r; _nss_dns_gethostbyname2_r; _nss_dns_gethostbyname_r; _nss_dns_getnetbyaddr_r; - _nss_dns_getnetbyname_r; + _nss_dns_getnetbyname_r; _nss_dns_getcanonname_r; } } diff --git a/resolv/nss_dns/dns-canon.c b/resolv/nss_dns/dns-canon.c new file mode 100644 index 0000000000..e5b38f5e7c --- /dev/null +++ b/resolv/nss_dns/dns-canon.c @@ -0,0 +1,137 @@ +/* Copyright (C) 2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2004. + + 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. */ + +#include <errno.h> +#include <netdb.h> +#include <resolv.h> +#include <stdlib.h> +#include <arpa/nameser.h> +#include <nsswitch.h> + + +#if PACKETSZ > 65536 +# define MAXPACKET PACKETSZ +#else +# define MAXPACKET 65536 +#endif + + +/* We need this time later. */ +typedef union querybuf +{ + HEADER hdr; + unsigned char buf[MAXPACKET]; +} querybuf; + + +enum nss_status +_nss_dns_getcanonname_r (const char *name, char *buffer, size_t buflen, + char **result,int *errnop, int *h_errnop) +{ + /* Just an alibi buffer, res_nquery will allocate a real buffer for + us. */ + unsigned char buf[20]; + union + { + querybuf *buf; + unsigned char *ptr; + } ansp = { .ptr = buf }; + enum nss_status status; + + int r = __libc_res_nquery (&_res, name, ns_c_in, ns_t_cname, + buf, sizeof (buf), &ansp.ptr); + if (r > 0) + { + /* We need to decode the response. Just one question record. + And if we got no answers we bail out, too. */ + if (ansp.buf->hdr.qdcount != htons (1) + || ansp.buf->hdr.ancount == 0) + goto unavail; + + /* Beginning and end of the buffer with query, answer, and the + rest. */ + unsigned char *ptr = &ansp.buf->buf[sizeof (HEADER)]; + unsigned char *endptr = ansp.ptr + r; + + /* Skip over the query. This is the name, type, and class. */ + int s = __dn_skipname (ptr, endptr); + if (s < 0) + goto unavail; + + /* Skip over the name and the two 16-bit values containing type + and class. */ + ptr += s + 2 * sizeof (uint16_t); + + /* Now the reply. First again the name from the query, then + type, class, TTL, and the length of the RDATA. */ + s = __dn_skipname (ptr, endptr); + if (s < 0) + goto unavail; + + ptr += s; + + /* Check whether type and class match. */ + if (*(uint16_t *) ptr != htons (ns_t_cname)) + goto unavail; + + ptr += sizeof (uint16_t); + if (*(uint16_t *) ptr != htons (ns_c_in)) + goto unavail; + + /* Also skip over the TTL and rdata length. */ + ptr += sizeof (uint16_t) + sizeof (uint32_t) + sizeof (int16_t); + + /* Now the name we are looking for. */ + s = __dn_expand (ansp.buf->buf, endptr, ptr, buffer, buflen); + if (s < 0) + { + if (errno != EMSGSIZE) + goto unavail; + + /* The buffer is too small. */ + *errnop = ERANGE; + status = NSS_STATUS_TRYAGAIN; + h_errno = NETDB_INTERNAL; + } + else + { + /* Success. */ + *result = buffer; + status = NSS_STATUS_SUCCESS; + } + } + else if (h_errno == TRY_AGAIN) + { + again: + status = NSS_STATUS_TRYAGAIN; + *errnop = errno; + } + else + { + unavail: + status = NSS_STATUS_UNAVAIL; + *errnop = errno; + } + *h_errnop = h_errno; + + if (ansp.ptr != buf) + free (ansp.ptr); + + return status; +} |