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-rw-r--r--lib/irs/resconf.c713
1 files changed, 713 insertions, 0 deletions
diff --git a/lib/irs/resconf.c b/lib/irs/resconf.c
new file mode 100644
index 0000000..2cd98aa
--- /dev/null
+++ b/lib/irs/resconf.c
@@ -0,0 +1,713 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file resconf.c */
+
+/**
+ * Module for parsing resolv.conf files (largely derived from lwconfig.c).
+ *
+ * irs_resconf_load() opens the file filename and parses it to initialize
+ * the configuration structure.
+ *
+ * \section lwconfig_return Return Values
+ *
+ * irs_resconf_load() returns #IRS_R_SUCCESS if it successfully read and
+ * parsed filename. It returns a non-0 error code if filename could not be
+ * opened or contained incorrect resolver statements.
+ *
+ * \section lwconfig_see See Also
+ *
+ * stdio(3), \link resolver resolver \endlink
+ *
+ * \section files Files
+ *
+ * /etc/resolv.conf
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netaddr.h>
+#include <isc/sockaddr.h>
+#include <isc/util.h>
+
+#include <irs/resconf.h>
+
+#define IRS_RESCONF_MAGIC ISC_MAGIC('R', 'E', 'S', 'c')
+#define IRS_RESCONF_VALID(c) ISC_MAGIC_VALID(c, IRS_RESCONF_MAGIC)
+
+/*!
+ * protocol constants
+ */
+
+#if !defined(NS_INADDRSZ)
+#define NS_INADDRSZ 4
+#endif /* if !defined(NS_INADDRSZ) */
+
+#if !defined(NS_IN6ADDRSZ)
+#define NS_IN6ADDRSZ 16
+#endif /* if !defined(NS_IN6ADDRSZ) */
+
+/*!
+ * resolv.conf parameters
+ */
+
+#define RESCONFMAXNAMESERVERS 3U /*%< max 3 "nameserver" entries */
+#define RESCONFMAXSEARCH 8U /*%< max 8 domains in "search" entry */
+#define RESCONFMAXLINELEN 256U /*%< max size of a line */
+#define RESCONFMAXSORTLIST 10U /*%< max 10 */
+
+#define CHECK(op) \
+ do { \
+ result = (op); \
+ if (result != ISC_R_SUCCESS) \
+ goto cleanup; \
+ } while (0)
+
+/*!
+ * configuration data structure
+ */
+
+struct irs_resconf {
+ /*
+ * The configuration data is a thread-specific object, and does not
+ * need to be locked.
+ */
+ unsigned int magic;
+ isc_mem_t *mctx;
+
+ isc_sockaddrlist_t nameservers;
+ unsigned int numns; /*%< number of configured servers
+ * */
+
+ char *domainname;
+ char *search[RESCONFMAXSEARCH];
+ uint8_t searchnxt; /*%< index for next free slot
+ * */
+
+ irs_resconf_searchlist_t searchlist;
+
+ struct {
+ isc_netaddr_t addr;
+ /*% mask has a non-zero 'family' if set */
+ isc_netaddr_t mask;
+ } sortlist[RESCONFMAXSORTLIST];
+ uint8_t sortlistnxt;
+
+ /*%< non-zero if 'options debug' set */
+ uint8_t resdebug;
+ /*%< set to n in 'options ndots:n' */
+ uint8_t ndots;
+ /*%< set to n in 'options attempts:n' */
+ uint8_t attempts;
+ /*%< set to n in 'options timeout:n' */
+ uint8_t timeout;
+};
+
+static isc_result_t
+resconf_parsenameserver(irs_resconf_t *conf, FILE *fp);
+static isc_result_t
+resconf_parsedomain(irs_resconf_t *conf, FILE *fp);
+static isc_result_t
+resconf_parsesearch(irs_resconf_t *conf, FILE *fp);
+static isc_result_t
+resconf_parsesortlist(irs_resconf_t *conf, FILE *fp);
+static isc_result_t
+resconf_parseoption(irs_resconf_t *ctx, FILE *fp);
+
+/*!
+ * Eat characters from FP until EOL or EOF. Returns EOF or '\n'
+ */
+static int
+eatline(FILE *fp) {
+ int ch;
+
+ ch = fgetc(fp);
+ while (ch != '\n' && ch != EOF) {
+ ch = fgetc(fp);
+ }
+
+ return (ch);
+}
+
+/*!
+ * Eats white space up to next newline or non-whitespace character (of
+ * EOF). Returns the last character read. Comments are considered white
+ * space.
+ */
+static int
+eatwhite(FILE *fp) {
+ int ch;
+
+ ch = fgetc(fp);
+ while (ch != '\n' && ch != EOF && isspace((unsigned char)ch)) {
+ ch = fgetc(fp);
+ }
+
+ if (ch == ';' || ch == '#') {
+ ch = eatline(fp);
+ }
+
+ return (ch);
+}
+
+/*!
+ * Skip over any leading whitespace and then read in the next sequence of
+ * non-whitespace characters. In this context newline is not considered
+ * whitespace. Returns EOF on end-of-file, or the character
+ * that caused the reading to stop.
+ */
+static int
+getword(FILE *fp, char *buffer, size_t size) {
+ char *p = NULL;
+ int ch;
+
+ REQUIRE(buffer != NULL);
+ REQUIRE(size > 0U);
+
+ p = buffer;
+ *p = '\0';
+
+ ch = eatwhite(fp);
+
+ if (ch == EOF) {
+ return (EOF);
+ }
+
+ do {
+ *p = '\0';
+
+ if (ch == EOF || isspace((unsigned char)ch)) {
+ break;
+ } else if ((size_t)(p - buffer) == size - 1) {
+ return (EOF); /* Not enough space. */
+ }
+
+ *p++ = (char)ch;
+ ch = fgetc(fp);
+ } while (1);
+
+ return (ch);
+}
+
+static isc_result_t
+add_server(isc_mem_t *mctx, const char *address_str,
+ isc_sockaddrlist_t *nameservers) {
+ int error;
+ isc_sockaddr_t *address = NULL;
+ struct addrinfo hints, *res;
+ isc_result_t result = ISC_R_SUCCESS;
+
+ res = NULL;
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = AF_UNSPEC;
+ hints.ai_socktype = SOCK_DGRAM;
+ hints.ai_protocol = IPPROTO_UDP;
+ hints.ai_flags = AI_NUMERICHOST;
+ error = getaddrinfo(address_str, "53", &hints, &res);
+ if (error != 0) {
+ return (ISC_R_BADADDRESSFORM);
+ }
+
+ /* XXX: special case: treat all-0 IPv4 address as loopback */
+ if (res->ai_family == AF_INET) {
+ struct in_addr *v4;
+ unsigned char zeroaddress[] = { 0, 0, 0, 0 };
+ unsigned char loopaddress[] = { 127, 0, 0, 1 };
+
+ v4 = &((struct sockaddr_in *)res->ai_addr)->sin_addr;
+ if (memcmp(v4, zeroaddress, 4) == 0) {
+ memmove(v4, loopaddress, 4);
+ }
+ }
+
+ address = isc_mem_get(mctx, sizeof(*address));
+ if (res->ai_addrlen > sizeof(address->type)) {
+ isc_mem_put(mctx, address, sizeof(*address));
+ result = ISC_R_RANGE;
+ goto cleanup;
+ }
+ address->length = (unsigned int)res->ai_addrlen;
+ memmove(&address->type.ss, res->ai_addr, res->ai_addrlen);
+ ISC_LINK_INIT(address, link);
+ ISC_LIST_APPEND(*nameservers, address, link);
+
+cleanup:
+ freeaddrinfo(res);
+
+ return (result);
+}
+
+static isc_result_t
+create_addr(const char *buffer, isc_netaddr_t *addr, int convert_zero) {
+ struct in_addr v4;
+ struct in6_addr v6;
+
+ if (inet_pton(AF_INET, buffer, &v4) == 1) {
+ if (convert_zero) {
+ unsigned char zeroaddress[] = { 0, 0, 0, 0 };
+ unsigned char loopaddress[] = { 127, 0, 0, 1 };
+ if (memcmp(&v4, zeroaddress, 4) == 0) {
+ memmove(&v4, loopaddress, 4);
+ }
+ }
+ addr->family = AF_INET;
+ memmove(&addr->type.in, &v4, NS_INADDRSZ);
+ addr->zone = 0;
+ } else if (inet_pton(AF_INET6, buffer, &v6) == 1) {
+ addr->family = AF_INET6;
+ memmove(&addr->type.in6, &v6, NS_IN6ADDRSZ);
+ addr->zone = 0;
+ } else {
+ return (ISC_R_BADADDRESSFORM); /* Unrecognised format. */
+ }
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_parsenameserver(irs_resconf_t *conf, FILE *fp) {
+ char word[RESCONFMAXLINELEN];
+ int cp;
+ isc_result_t result;
+
+ cp = getword(fp, word, sizeof(word));
+ if (strlen(word) == 0U) {
+ return (ISC_R_UNEXPECTEDEND); /* Nothing on line. */
+ } else if (cp == ' ' || cp == '\t') {
+ cp = eatwhite(fp);
+ }
+
+ if (cp != EOF && cp != '\n') {
+ return (ISC_R_UNEXPECTEDTOKEN); /* Extra junk on line. */
+ }
+
+ if (conf->numns == RESCONFMAXNAMESERVERS) {
+ return (ISC_R_SUCCESS);
+ }
+
+ result = add_server(conf->mctx, word, &conf->nameservers);
+ if (result != ISC_R_SUCCESS) {
+ return (result);
+ }
+ conf->numns++;
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_parsedomain(irs_resconf_t *conf, FILE *fp) {
+ char word[RESCONFMAXLINELEN];
+ int res;
+ unsigned int i;
+
+ res = getword(fp, word, sizeof(word));
+ if (strlen(word) == 0U) {
+ return (ISC_R_UNEXPECTEDEND); /* Nothing else on line. */
+ } else if (res == ' ' || res == '\t') {
+ res = eatwhite(fp);
+ }
+
+ if (res != EOF && res != '\n') {
+ return (ISC_R_UNEXPECTEDTOKEN); /* Extra junk on line. */
+ }
+
+ if (conf->domainname != NULL) {
+ isc_mem_free(conf->mctx, conf->domainname);
+ }
+
+ /*
+ * Search and domain are mutually exclusive.
+ */
+ for (i = 0; i < RESCONFMAXSEARCH; i++) {
+ if (conf->search[i] != NULL) {
+ isc_mem_free(conf->mctx, conf->search[i]);
+ conf->search[i] = NULL;
+ }
+ }
+ conf->searchnxt = 0;
+
+ conf->domainname = isc_mem_strdup(conf->mctx, word);
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_parsesearch(irs_resconf_t *conf, FILE *fp) {
+ int delim;
+ unsigned int idx;
+ char word[RESCONFMAXLINELEN];
+
+ if (conf->domainname != NULL) {
+ /*
+ * Search and domain are mutually exclusive.
+ */
+ isc_mem_free(conf->mctx, conf->domainname);
+ conf->domainname = NULL;
+ }
+
+ /*
+ * Remove any previous search definitions.
+ */
+ for (idx = 0; idx < RESCONFMAXSEARCH; idx++) {
+ if (conf->search[idx] != NULL) {
+ isc_mem_free(conf->mctx, conf->search[idx]);
+ conf->search[idx] = NULL;
+ }
+ }
+ conf->searchnxt = 0;
+
+ delim = getword(fp, word, sizeof(word));
+ if (strlen(word) == 0U) {
+ return (ISC_R_UNEXPECTEDEND); /* Nothing else on line. */
+ }
+
+ idx = 0;
+ while (strlen(word) > 0U) {
+ if (conf->searchnxt == RESCONFMAXSEARCH) {
+ goto ignore; /* Too many domains. */
+ }
+
+ INSIST(idx < sizeof(conf->search) / sizeof(conf->search[0]));
+ conf->search[idx] = isc_mem_strdup(conf->mctx, word);
+ idx++;
+ conf->searchnxt++;
+
+ ignore:
+ if (delim == EOF || delim == '\n') {
+ break;
+ } else {
+ delim = getword(fp, word, sizeof(word));
+ }
+ }
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_parsesortlist(irs_resconf_t *conf, FILE *fp) {
+ int delim, res;
+ unsigned int idx;
+ char word[RESCONFMAXLINELEN];
+ char *p;
+
+ delim = getword(fp, word, sizeof(word));
+ if (strlen(word) == 0U) {
+ return (ISC_R_UNEXPECTEDEND); /* Empty line after keyword. */
+ }
+
+ while (strlen(word) > 0U) {
+ if (conf->sortlistnxt == RESCONFMAXSORTLIST) {
+ return (ISC_R_QUOTA); /* Too many values. */
+ }
+
+ p = strchr(word, '/');
+ if (p != NULL) {
+ *p++ = '\0';
+ }
+
+ idx = conf->sortlistnxt;
+ INSIST(idx <
+ sizeof(conf->sortlist) / sizeof(conf->sortlist[0]));
+ res = create_addr(word, &conf->sortlist[idx].addr, 1);
+ if (res != ISC_R_SUCCESS) {
+ return (res);
+ }
+
+ if (p != NULL) {
+ res = create_addr(p, &conf->sortlist[idx].mask, 0);
+ if (res != ISC_R_SUCCESS) {
+ return (res);
+ }
+ } else {
+ /*
+ * Make up a mask. (XXX: is this correct?)
+ */
+ conf->sortlist[idx].mask = conf->sortlist[idx].addr;
+ memset(&conf->sortlist[idx].mask.type, 0xff,
+ sizeof(conf->sortlist[idx].mask.type));
+ }
+
+ conf->sortlistnxt++;
+
+ if (delim == EOF || delim == '\n') {
+ break;
+ } else {
+ delim = getword(fp, word, sizeof(word));
+ }
+ }
+
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_optionnumber(const char *word, uint8_t *number) {
+ char *p;
+ long n;
+
+ n = strtol(word, &p, 10);
+ if (*p != '\0') { /* Bad string. */
+ return (ISC_R_UNEXPECTEDTOKEN);
+ }
+ if (n < 0 || n > 0xff) { /* Out of range. */
+ return (ISC_R_RANGE);
+ }
+ *number = n;
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
+ int delim;
+ isc_result_t result = ISC_R_SUCCESS;
+ char word[RESCONFMAXLINELEN];
+
+ delim = getword(fp, word, sizeof(word));
+ if (strlen(word) == 0U) {
+ return (ISC_R_UNEXPECTEDEND); /* Empty line after keyword. */
+ }
+
+ while (strlen(word) > 0U) {
+ if (strcmp("debug", word) == 0) {
+ conf->resdebug = 1;
+ } else if (strncmp("ndots:", word, 6) == 0) {
+ CHECK(resconf_optionnumber(word + 6, &conf->ndots));
+ } else if (strncmp("attempts:", word, 9) == 0) {
+ CHECK(resconf_optionnumber(word + 9, &conf->attempts));
+ } else if (strncmp("timeout:", word, 8) == 0) {
+ CHECK(resconf_optionnumber(word + 8, &conf->timeout));
+ }
+
+ if (delim == EOF || delim == '\n') {
+ break;
+ } else {
+ delim = getword(fp, word, sizeof(word));
+ }
+ }
+
+cleanup:
+ return (result);
+}
+
+static isc_result_t
+add_search(irs_resconf_t *conf, char *domain) {
+ irs_resconf_search_t *entry;
+
+ entry = isc_mem_get(conf->mctx, sizeof(*entry));
+
+ entry->domain = domain;
+ ISC_LINK_INIT(entry, link);
+ ISC_LIST_APPEND(conf->searchlist, entry, link);
+
+ return (ISC_R_SUCCESS);
+}
+
+/*% parses a file and fills in the data structure. */
+isc_result_t
+irs_resconf_load(isc_mem_t *mctx, const char *filename, irs_resconf_t **confp) {
+ FILE *fp = NULL;
+ char word[256];
+ isc_result_t rval, ret = ISC_R_SUCCESS;
+ irs_resconf_t *conf;
+ unsigned int i;
+ int stopchar;
+
+ REQUIRE(mctx != NULL);
+ REQUIRE(filename != NULL);
+ REQUIRE(strlen(filename) > 0U);
+ REQUIRE(confp != NULL && *confp == NULL);
+
+ conf = isc_mem_get(mctx, sizeof(*conf));
+
+ conf->mctx = mctx;
+ ISC_LIST_INIT(conf->nameservers);
+ ISC_LIST_INIT(conf->searchlist);
+ conf->numns = 0;
+ conf->domainname = NULL;
+ conf->searchnxt = 0;
+ conf->sortlistnxt = 0;
+ conf->resdebug = 0;
+ conf->ndots = 1;
+ conf->attempts = 3;
+ conf->timeout = 0;
+ for (i = 0; i < RESCONFMAXSEARCH; i++) {
+ conf->search[i] = NULL;
+ }
+
+ errno = 0;
+ if ((fp = fopen(filename, "r")) != NULL) {
+ do {
+ stopchar = getword(fp, word, sizeof(word));
+ if (stopchar == EOF) {
+ rval = ISC_R_SUCCESS;
+ POST(rval);
+ break;
+ }
+
+ if (strlen(word) == 0U) {
+ rval = ISC_R_SUCCESS;
+ } else if (strcmp(word, "nameserver") == 0) {
+ rval = resconf_parsenameserver(conf, fp);
+ } else if (strcmp(word, "domain") == 0) {
+ rval = resconf_parsedomain(conf, fp);
+ } else if (strcmp(word, "search") == 0) {
+ rval = resconf_parsesearch(conf, fp);
+ } else if (strcmp(word, "sortlist") == 0) {
+ rval = resconf_parsesortlist(conf, fp);
+ } else if (strcmp(word, "options") == 0) {
+ rval = resconf_parseoption(conf, fp);
+ } else {
+ /* unrecognised word. Ignore entire line */
+ rval = ISC_R_SUCCESS;
+ stopchar = eatline(fp);
+ if (stopchar == EOF) {
+ break;
+ }
+ }
+ if (ret == ISC_R_SUCCESS && rval != ISC_R_SUCCESS) {
+ ret = rval;
+ }
+ } while (1);
+
+ fclose(fp);
+ } else {
+ switch (errno) {
+ case ENOENT:
+ break;
+ default:
+ isc_mem_put(mctx, conf, sizeof(*conf));
+ return (ISC_R_INVALIDFILE);
+ }
+ }
+
+ if (ret != ISC_R_SUCCESS) {
+ goto error;
+ }
+
+ /*
+ * Construct unified search list from domain or configured
+ * search list
+ */
+ if (conf->domainname != NULL) {
+ ret = add_search(conf, conf->domainname);
+ } else if (conf->searchnxt > 0) {
+ for (i = 0; i < conf->searchnxt; i++) {
+ ret = add_search(conf, conf->search[i]);
+ if (ret != ISC_R_SUCCESS) {
+ break;
+ }
+ }
+ }
+
+ /* If we don't find a nameserver fall back to localhost */
+ if (conf->numns == 0U) {
+ INSIST(ISC_LIST_EMPTY(conf->nameservers));
+
+ /* XXX: should we catch errors? */
+ (void)add_server(conf->mctx, "::1", &conf->nameservers);
+ (void)add_server(conf->mctx, "127.0.0.1", &conf->nameservers);
+ }
+
+error:
+ conf->magic = IRS_RESCONF_MAGIC;
+
+ if (ret != ISC_R_SUCCESS) {
+ irs_resconf_destroy(&conf);
+ } else {
+ if (fp == NULL) {
+ ret = ISC_R_FILENOTFOUND;
+ }
+ *confp = conf;
+ }
+
+ return (ret);
+}
+
+void
+irs_resconf_destroy(irs_resconf_t **confp) {
+ irs_resconf_t *conf;
+ isc_sockaddr_t *address;
+ irs_resconf_search_t *searchentry;
+ unsigned int i;
+
+ REQUIRE(confp != NULL);
+ conf = *confp;
+ *confp = NULL;
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ while ((searchentry = ISC_LIST_HEAD(conf->searchlist)) != NULL) {
+ ISC_LIST_UNLINK(conf->searchlist, searchentry, link);
+ isc_mem_put(conf->mctx, searchentry, sizeof(*searchentry));
+ }
+
+ while ((address = ISC_LIST_HEAD(conf->nameservers)) != NULL) {
+ ISC_LIST_UNLINK(conf->nameservers, address, link);
+ isc_mem_put(conf->mctx, address, sizeof(*address));
+ }
+
+ if (conf->domainname != NULL) {
+ isc_mem_free(conf->mctx, conf->domainname);
+ }
+
+ for (i = 0; i < RESCONFMAXSEARCH; i++) {
+ if (conf->search[i] != NULL) {
+ isc_mem_free(conf->mctx, conf->search[i]);
+ }
+ }
+
+ isc_mem_put(conf->mctx, conf, sizeof(*conf));
+}
+
+isc_sockaddrlist_t *
+irs_resconf_getnameservers(irs_resconf_t *conf) {
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ return (&conf->nameservers);
+}
+
+irs_resconf_searchlist_t *
+irs_resconf_getsearchlist(irs_resconf_t *conf) {
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ return (&conf->searchlist);
+}
+
+unsigned int
+irs_resconf_getndots(irs_resconf_t *conf) {
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ return ((unsigned int)conf->ndots);
+}
+
+unsigned int
+irs_resconf_getattempts(irs_resconf_t *conf) {
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ return ((unsigned int)conf->attempts);
+}
+
+unsigned int
+irs_resconf_gettimeout(irs_resconf_t *conf) {
+ REQUIRE(IRS_RESCONF_VALID(conf));
+
+ return ((unsigned int)conf->timeout);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-03 22:44:06 +0000