Add the fedfs domain information discovery library functions. Signed-off-by: Ian Kent <raven@xxxxxxxxxx> --- CHANGELOG | 1 fedfs/fedfs-getsrvinfo.c | 311 ++++++++++++++++++++++++++++++++++++++++++++++ fedfs/fedfs-getsrvinfo.h | 52 ++++++++ 3 files changed, 364 insertions(+) create mode 100644 fedfs/fedfs-getsrvinfo.c create mode 100644 fedfs/fedfs-getsrvinfo.h diff --git a/CHANGELOG b/CHANGELOG index dbfb8389..8d6c737c 100644 --- a/CHANGELOG +++ b/CHANGELOG @@ -14,6 +14,7 @@ xx/xx/2018 autofs-5.1.5 - Makefiles.rules: remove 'samples' from SUBDIRS. - dont allow trailing slash in master map mount points. - fix libresolv configure check. +- add fedfs-getsrvinfo.c. 19/12/2017 autofs-5.1.4 - fix spec file url. diff --git a/fedfs/fedfs-getsrvinfo.c b/fedfs/fedfs-getsrvinfo.c new file mode 100644 index 00000000..02ad16b5 --- /dev/null +++ b/fedfs/fedfs-getsrvinfo.c @@ -0,0 +1,311 @@ +/* + * Copyright 2011 Oracle. All rights reserved. + * + * This file is part of fedfs-utils. + * + * fedfs-utils is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2.0 as + * published by the Free Software Foundation. + * + * fedfs-utils 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 General Public License version 2.0 for more details. + * + * You should have received a copy of the GNU General Public License + * version 2.0 along with fedfs-utils. If not, see: + * + * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <sys/types.h> +#include <sys/socket.h> + +#include <stdbool.h> +#include <string.h> +#include <unistd.h> +#include <stdlib.h> +#include <stdint.h> + +#include <stdio.h> +#include <errno.h> +#include <netdb.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <arpa/nameser.h> +#include <arpa/nameser_compat.h> +#include <resolv.h> + +#include "fedfs-getsrvinfo.h" + +/** + * Parsing overlay for DNS query result record header. Fields are + * in network byte order. + */ +struct rechdr { + uint16_t type; + uint16_t class; + uint32_t ttl; + uint16_t length; +} __attribute__((__packed__)); + +/** + * Parsing overlay for DNS query result SRV record data. Fields + * are in network byte order. + */ +struct srv { + uint16_t priority; + uint16_t weight; + uint16_t port; + unsigned char *target; +} __attribute__((__packed__)); + +/** + * Return C string matching error value of "status" + * + * @param status error status returned by getsrvinfo + * @return pointer to static NUL-terminated C string containing error message + */ +const char * +gsi_strerror(int status) +{ + static char buf[256]; + + switch (status) { + case ESI_SUCCESS: + return "Success"; + case ESI_NONAME: + return "Name not found"; + case ESI_AGAIN: + return "Temporary failure in name resolution"; + case ESI_FAIL: + return "Non-recoverable failure in name resolution"; + case ESI_NODATA: + return "No SRV record returned"; + case ESI_SERVICE: + return "Service is not available"; + case ESI_MEMORY: + return "Memory allocation failure"; + case ESI_SYSTEM: + snprintf(buf, sizeof(buf), "System error (%d): %s", + status, strerror(errno)); + return buf; + case ESI_PARSE: + return "Failed to parse server response"; + } + + snprintf(buf, sizeof(buf), "Unknown error (%d)", status); + return buf; +} + +/** + * Release a list of SRV records allocated by getsrvinfo() + * + * @param si pointer to first element of a list of struct srvinfo + * + */ +void freesrvinfo(struct srvinfo *si) +{ + struct srvinfo *tmp; + + while (si != NULL) { + tmp = si; + si = si->si_next; + free(tmp->si_target); + free(tmp); + } +} + +/** + * Ordering predicate for srvinfo lists + * + * @param a a srvinfo list element to compare + * @param b another srvinfo list element to compare + * @return true if "b" should fall later in the list than "a" + * + * See RFC 2782. The list is ordered as follows: + * + * o Lowest priority first. + * o In each priority class, highest weight first. + */ +static _Bool +srvinfo_is_after(const struct srvinfo *a, const struct srvinfo *b) +{ + if (a->si_priority > b->si_priority) + return true; + if (a->si_priority < b->si_priority) + return false; + + if (a->si_weight < b->si_weight) + return true; + return false; +} + +/** + * Insert a srvinfo element into a list + * + * @param head pointer to head of list of elements + * @param entry new list element to insert + * + */ +static void +insert_srvinfo(struct srvinfo **head, struct srvinfo *entry) +{ + entry->si_next = *head; + *head = entry; +} + +/** + * Insert a srvinfo element into a list, in order + * + * @param head pointer to head of list of elements + * @param entry new list element to insert + * + */ +static void +insert_srvinfo_sorted(struct srvinfo **head, struct srvinfo *entry) +{ + struct srvinfo *spot, *back; + + spot = *head; + back = NULL; + while (spot && srvinfo_is_after(spot, entry)) { + back = spot; + spot = spot->si_next; + } + + if (spot == (*head)) + insert_srvinfo(head, entry); + else { + insert_srvinfo(&spot, entry); + /* off the end of the list? */ + if (spot == entry) + back->si_next = entry; + } +} + +/** + * Retrieve list of SRV records from DNS service + * + * @param srvname NUL-terminated C string containing record type to look up + * @param domainname NUL-terminated C string containing domain name to look up + * @param si OUT: list of SRV record information retrieved + * @return zero on success, or an ESI_ status code describing the error + * + * Caller must free list of records using freesrvinfo(). + */ +int +getsrvinfo(const char *srvname, const char *domainname, struct srvinfo **si) +{ + unsigned char *msg, *eom, *comp_dn; + struct srvinfo *results; + unsigned short count, i; + int status, len; + char *exp_dn; + HEADER *hdr; + + msg = calloc(1, NS_MAXMSG); + exp_dn = calloc(1, NS_MAXDNAME); + if (msg == NULL || exp_dn == NULL) { + status = ESI_MEMORY; + goto out; + } + + _res.options |= RES_AAONLY; + len = res_querydomain(srvname, domainname, C_IN, T_SRV, msg, NS_MAXMSG); + if (len == -1) { + switch (h_errno) { + case HOST_NOT_FOUND: + status = ESI_NONAME; + break; + case TRY_AGAIN: + status = ESI_AGAIN; + break; + case NO_RECOVERY: + status = ESI_FAIL; + break; + case NO_DATA: + status = ESI_NODATA; + break; + default: + fprintf(stderr, "SRV query failed for %s.%s: %s\n", + srvname, domainname, hstrerror(h_errno)); + status = ESI_FAIL; + } + goto out; + } + + hdr = (HEADER *)msg; + count = ntohs(hdr->ancount); + if (count == 0) { + status = ESI_NODATA; + goto out; + } + eom = msg + len; + + comp_dn = &msg[HFIXEDSZ]; + comp_dn += dn_skipname(comp_dn, eom) + QFIXEDSZ; + + results = NULL; + for (i = 0; i < count; i++) { + struct srvinfo *new; + struct srv *record; + int l; + + l = dn_expand(msg, eom, comp_dn, exp_dn, NS_MAXDNAME); + if (l == -1) { + status = ESI_PARSE; + goto out_free; + } + comp_dn += l; + + record = (struct srv *)&comp_dn[10]; + comp_dn += 16; + + l = dn_expand(msg, eom, comp_dn, exp_dn, NS_MAXDNAME); + if (l == -1) { + status = ESI_PARSE; + goto out_free; + } + comp_dn += l; + + if (count == 1 && strcmp(exp_dn, ".") == 0) { + status = ESI_SERVICE; + goto out_free; + } + + new = calloc(1, sizeof(*new)); + if (new == NULL) { + status = ESI_MEMORY; + goto out; + } + + new->si_target = strdup(exp_dn); + if (new->si_target == NULL) { + free(new); + status = ESI_MEMORY; + goto out; + } + new->si_priority = ntohs(record->priority); + new->si_weight = ntohs(record->weight); + new->si_port = ntohs(record->port); + + insert_srvinfo_sorted(&results, new); + } + + status = ESI_SUCCESS; + *si = results; + +out: + free(exp_dn); + free(msg); + return status; + +out_free: + freesrvinfo(results); + goto out; +} diff --git a/fedfs/fedfs-getsrvinfo.h b/fedfs/fedfs-getsrvinfo.h new file mode 100644 index 00000000..13170359 --- /dev/null +++ b/fedfs/fedfs-getsrvinfo.h @@ -0,0 +1,52 @@ +/* + * Copyright 2011 Oracle. All rights reserved. + * + * This file is part of fedfs-utils. + * + * fedfs-utils is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2.0 as + * published by the Free Software Foundation. + * + * fedfs-utils 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 General Public License version 2.0 for more details. + * + * You should have received a copy of the GNU General Public License + * version 2.0 along with fedfs-utils. If not, see: + * + * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt + */ + +#ifndef _FEDFS_GETSRVINFO_H_ +#define _FEDFS_GETSRVINFO_H_ + +/** + * Single list element containing SRV record data + */ +struct srvinfo { + struct srvinfo *si_next; + char *si_target; + unsigned short si_priority; + unsigned short si_weight; + unsigned short si_port; +}; + +enum { + ESI_SUCCESS = 0, + ESI_NONAME = -2, + ESI_AGAIN = -3, + ESI_FAIL = -4, + ESI_NODATA = -5, + ESI_SERVICE = -8, + ESI_MEMORY = -10, + ESI_SYSTEM = -11, + ESI_PARSE = -1000, +}; + +int getsrvinfo(const char *srvname, const char *domainname, + struct srvinfo **si); +void freesrvinfo(struct srvinfo *si); +const char *gsi_strerror(int status); + +#endif /* !_FEDFS_GETSRVINFO_H_ */ -- To unsubscribe from this list: send the line "unsubscribe autofs" in
