diff options
Diffstat (limited to 'resolv/ns_name_skip.c')
-rw-r--r-- | resolv/ns_name_skip.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/resolv/ns_name_skip.c b/resolv/ns_name_skip.c new file mode 100644 index 0000000..c26d658 --- /dev/null +++ b/resolv/ns_name_skip.c @@ -0,0 +1,70 @@ +/* Skip over a (potentially compressed) domain name in wire format. + * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") + * Copyright (c) 1996,1999 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT + * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <arpa/nameser.h> +#include <errno.h> +#include <shlib-compat.h> + +/* Advances *PTRPTR to skip over the compressed name it points at. + Returns 0 on success, -1 (with errno set) on failure. */ +int +___ns_name_skip (const unsigned char **ptrptr, const unsigned char *eom) +{ + const unsigned char *cp; + unsigned int n; + + cp = *ptrptr; + while (cp < eom) + { + n = *cp++; + if (n == 0) + { + /* End of domain name without indirection. */ + *ptrptr = cp; + return 0; + } + + /* Check for indirection. */ + switch (n & NS_CMPRSFLGS) + { + case 0: /* Normal case, n == len. */ + if (eom - cp < n) + goto malformed; + cp += n; + break; + case NS_CMPRSFLGS: /* Indirection. */ + if (cp == eom) + /* No room for second indirection byte. */ + goto malformed; + *ptrptr = cp + 1; + return 0; + default: /* Illegal type. */ + goto malformed; + } + } + + malformed: + __set_errno (EMSGSIZE); + return -1; +} +versioned_symbol (libc, ___ns_name_skip, ns_name_skip, GLIBC_2_34); +versioned_symbol (libc, ___ns_name_skip, __ns_name_skip, GLIBC_PRIVATE); +libc_hidden_ver (___ns_name_skip, __ns_name_skip) + +#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_9, GLIBC_2_34) +compat_symbol (libresolv, ___ns_name_skip, ns_name_skip, GLIBC_2_9); +#endif |