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git01.mediatek.com / haproxy / 7f59d68fe272c677e577523b3fe866f2b22a56ab / . / src / resolvers.c
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/*
* Name server resolution
*
* Copyright 2014 Baptiste Assmann <bedis9@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <import/ebistree.h>
#include <haproxy/action.h>
#include <haproxy/api.h>
#include <haproxy/applet.h>
#include <haproxy/cfgparse.h>
#include <haproxy/channel.h>
#include <haproxy/check.h>
#include <haproxy/cli.h>
#include <haproxy/dns.h>
#include <haproxy/errors.h>
#include <haproxy/fd.h>
#include <haproxy/http_rules.h>
#include <haproxy/log.h>
#include <haproxy/net_helper.h>
#include <haproxy/protocol.h>
#include <haproxy/proxy.h>
#include <haproxy/resolvers.h>
#include <haproxy/ring.h>
#include <haproxy/sample.h>
#include <haproxy/sc_strm.h>
#include <haproxy/server.h>
#include <haproxy/stats.h>
#include <haproxy/stconn.h>
#include <haproxy/task.h>
#include <haproxy/tcp_rules.h>
#include <haproxy/ticks.h>
#include <haproxy/time.h>
#include <haproxy/tools.h>
#include <haproxy/vars.h>
#include <haproxy/xxhash.h>
struct list sec_resolvers = LIST_HEAD_INIT(sec_resolvers);
struct list resolv_srvrq_list = LIST_HEAD_INIT(resolv_srvrq_list);
static THREAD_LOCAL struct list death_row; /* list of deferred resolutions to kill, local validity only */
static THREAD_LOCAL unsigned int recurse = 0; /* counter to track calls to public functions */
static THREAD_LOCAL uint64_t resolv_query_id_seed = 0; /* random seed */
struct resolvers *curr_resolvers = NULL;
DECLARE_STATIC_POOL(resolv_answer_item_pool, "resolv_answer_item", sizeof(struct resolv_answer_item));
DECLARE_STATIC_POOL(resolv_resolution_pool, "resolv_resolution", sizeof(struct resolv_resolution));
DECLARE_POOL(resolv_requester_pool, "resolv_requester", sizeof(struct resolv_requester));
static unsigned int resolution_uuid = 1;
unsigned int resolv_failed_resolutions = 0;
struct task *process_resolvers(struct task *t, void *context, unsigned int state);
static void resolv_free_resolution(struct resolv_resolution *resolution);
static void _resolv_unlink_resolution(struct resolv_requester *requester);
static void enter_resolver_code();
static void leave_resolver_code();
enum {
RSLV_STAT_ID,
RSLV_STAT_PID,
RSLV_STAT_SENT,
RSLV_STAT_SND_ERROR,
RSLV_STAT_VALID,
RSLV_STAT_UPDATE,
RSLV_STAT_CNAME,
RSLV_STAT_CNAME_ERROR,
RSLV_STAT_ANY_ERR,
RSLV_STAT_NX,
RSLV_STAT_TIMEOUT,
RSLV_STAT_REFUSED,
RSLV_STAT_OTHER,
RSLV_STAT_INVALID,
RSLV_STAT_TOO_BIG,
RSLV_STAT_TRUNCATED,
RSLV_STAT_OUTDATED,
RSLV_STAT_END,
};
static struct name_desc resolv_stats[] = {
[RSLV_STAT_ID] = { .name = "id", .desc = "ID" },
[RSLV_STAT_PID] = { .name = "pid", .desc = "Parent ID" },
[RSLV_STAT_SENT] = { .name = "sent", .desc = "Sent" },
[RSLV_STAT_SND_ERROR] = { .name = "send_error", .desc = "Send error" },
[RSLV_STAT_VALID] = { .name = "valid", .desc = "Valid" },
[RSLV_STAT_UPDATE] = { .name = "update", .desc = "Update" },
[RSLV_STAT_CNAME] = { .name = "cname", .desc = "CNAME" },
[RSLV_STAT_CNAME_ERROR] = { .name = "cname_error", .desc = "CNAME error" },
[RSLV_STAT_ANY_ERR] = { .name = "any_err", .desc = "Any errors" },
[RSLV_STAT_NX] = { .name = "nx", .desc = "NX" },
[RSLV_STAT_TIMEOUT] = { .name = "timeout", .desc = "Timeout" },
[RSLV_STAT_REFUSED] = { .name = "refused", .desc = "Refused" },
[RSLV_STAT_OTHER] = { .name = "other", .desc = "Other" },
[RSLV_STAT_INVALID] = { .name = "invalid", .desc = "Invalid" },
[RSLV_STAT_TOO_BIG] = { .name = "too_big", .desc = "Too big" },
[RSLV_STAT_TRUNCATED] = { .name = "truncated", .desc = "Truncated" },
[RSLV_STAT_OUTDATED] = { .name = "outdated", .desc = "Outdated" },
};
static struct dns_counters dns_counters;
static void resolv_fill_stats(void *d, struct field *stats)
{
struct dns_counters *counters = d;
stats[RSLV_STAT_ID] = mkf_str(FO_CONFIG, counters->id);
stats[RSLV_STAT_PID] = mkf_str(FO_CONFIG, counters->pid);
stats[RSLV_STAT_SENT] = mkf_u64(FN_GAUGE, counters->sent);
stats[RSLV_STAT_SND_ERROR] = mkf_u64(FN_GAUGE, counters->snd_error);
stats[RSLV_STAT_VALID] = mkf_u64(FN_GAUGE, counters->app.resolver.valid);
stats[RSLV_STAT_UPDATE] = mkf_u64(FN_GAUGE, counters->app.resolver.update);
stats[RSLV_STAT_CNAME] = mkf_u64(FN_GAUGE, counters->app.resolver.cname);
stats[RSLV_STAT_CNAME_ERROR] = mkf_u64(FN_GAUGE, counters->app.resolver.cname_error);
stats[RSLV_STAT_ANY_ERR] = mkf_u64(FN_GAUGE, counters->app.resolver.any_err);
stats[RSLV_STAT_NX] = mkf_u64(FN_GAUGE, counters->app.resolver.nx);
stats[RSLV_STAT_TIMEOUT] = mkf_u64(FN_GAUGE, counters->app.resolver.timeout);
stats[RSLV_STAT_REFUSED] = mkf_u64(FN_GAUGE, counters->app.resolver.refused);
stats[RSLV_STAT_OTHER] = mkf_u64(FN_GAUGE, counters->app.resolver.other);
stats[RSLV_STAT_INVALID] = mkf_u64(FN_GAUGE, counters->app.resolver.invalid);
stats[RSLV_STAT_TOO_BIG] = mkf_u64(FN_GAUGE, counters->app.resolver.too_big);
stats[RSLV_STAT_TRUNCATED] = mkf_u64(FN_GAUGE, counters->app.resolver.truncated);
stats[RSLV_STAT_OUTDATED] = mkf_u64(FN_GAUGE, counters->app.resolver.outdated);
}
static struct stats_module rslv_stats_module = {
.name = "resolvers",
.domain_flags = STATS_DOMAIN_RESOLVERS << STATS_DOMAIN,
.fill_stats = resolv_fill_stats,
.stats = resolv_stats,
.stats_count = RSLV_STAT_END,
.counters = &dns_counters,
.counters_size = sizeof(dns_counters),
.clearable = 0,
};
INITCALL1(STG_REGISTER, stats_register_module, &rslv_stats_module);
/* CLI context used during "show resolvers" */
struct show_resolvers_ctx {
struct resolvers *forced_section;
struct resolvers *resolvers;
struct dns_nameserver *ns;
};
/* Returns a pointer to the resolvers matching the id <id>. NULL is returned if
* no match is found.
*/
struct resolvers *find_resolvers_by_id(const char *id)
{
struct resolvers *res;
list_for_each_entry(res, &sec_resolvers, list) {
if (strcmp(res->id, id) == 0)
return res;
}
return NULL;
}
/* Returns a pointer on the SRV request matching the name <name> for the proxy
* <px>. NULL is returned if no match is found.
*/
struct resolv_srvrq *find_srvrq_by_name(const char *name, struct proxy *px)
{
struct resolv_srvrq *srvrq;
list_for_each_entry(srvrq, &resolv_srvrq_list, list) {
if (srvrq->proxy == px && strcmp(srvrq->name, name) == 0)
return srvrq;
}
return NULL;
}
/* Allocates a new SRVRQ for the given server with the name <fqdn>. It returns
* NULL if an error occurred. */
struct resolv_srvrq *new_resolv_srvrq(struct server *srv, char *fqdn)
{
struct proxy *px = srv->proxy;
struct resolv_srvrq *srvrq = NULL;
int fqdn_len, hostname_dn_len;
fqdn_len = strlen(fqdn);
hostname_dn_len = resolv_str_to_dn_label(fqdn, fqdn_len, trash.area,
trash.size);
if (hostname_dn_len == -1) {
ha_alert("%s '%s', server '%s': failed to parse FQDN '%s'\n",
proxy_type_str(px), px->id, srv->id, fqdn);
goto err;
}
if ((srvrq = calloc(1, sizeof(*srvrq))) == NULL) {
ha_alert("%s '%s', server '%s': out of memory\n",
proxy_type_str(px), px->id, srv->id);
goto err;
}
srvrq->obj_type = OBJ_TYPE_SRVRQ;
srvrq->proxy = px;
srvrq->name = strdup(fqdn);
srvrq->hostname_dn = strdup(trash.area);
srvrq->hostname_dn_len = hostname_dn_len;
if (!srvrq->name || !srvrq->hostname_dn) {
ha_alert("%s '%s', server '%s': out of memory\n",
proxy_type_str(px), px->id, srv->id);
goto err;
}
LIST_INIT(&srvrq->attached_servers);
srvrq->named_servers = EB_ROOT;
LIST_APPEND(&resolv_srvrq_list, &srvrq->list);
return srvrq;
err:
if (srvrq) {
free(srvrq->name);
free(srvrq->hostname_dn);
free(srvrq);
}
return NULL;
}
/* finds and return the SRV answer item associated to a requester (whose type is 'server').
*
* returns NULL in case of error or not found.
*/
struct resolv_answer_item *find_srvrq_answer_record(const struct resolv_requester *requester)
{
struct resolv_resolution *res;
struct eb32_node *eb32;
struct server *srv;
if (!requester)
return NULL;
if ((srv = objt_server(requester->owner)) == NULL)
return NULL;
/* check if the server is managed by a SRV record */
if (srv->srvrq == NULL)
return NULL;
res = srv->srvrq->requester->resolution;
/* search an ANSWER record whose target points to the server's hostname and whose port is
* the same as server's svc_port */
for (eb32 = eb32_first(&res->response.answer_tree); eb32 != NULL; eb32 = eb32_next(eb32)) {
struct resolv_answer_item *item = eb32_entry(eb32, typeof(*item), link);
if (memcmp(srv->hostname_dn, item->data.target, srv->hostname_dn_len) == 0 &&
(srv->svc_port == item->port))
return item;
}
return NULL;
}
/* 2 bytes random generator to generate DNS query ID */
static inline uint16_t resolv_rnd16(void)
{
if (!resolv_query_id_seed)
resolv_query_id_seed = now_ms;
resolv_query_id_seed ^= resolv_query_id_seed << 13;
resolv_query_id_seed ^= resolv_query_id_seed >> 7;
resolv_query_id_seed ^= resolv_query_id_seed << 17;
return resolv_query_id_seed;
}
static inline int resolv_resolution_timeout(struct resolv_resolution *res)
{
return res->resolvers->timeout.resolve;
}
/* Updates a resolvers' task timeout for next wake up and queue it */
static void resolv_update_resolvers_timeout(struct resolvers *resolvers)
{
struct resolv_resolution *res;
int next = TICK_ETERNITY;
if (!LIST_ISEMPTY(&resolvers->resolutions.curr)) {
res = LIST_NEXT(&resolvers->resolutions.curr, struct resolv_resolution *, list);
next = tick_add(now_ms, resolvers->timeout.resolve);
next = MIN(next, tick_add(res->last_query, resolvers->timeout.retry));
}
list_for_each_entry(res, &resolvers->resolutions.wait, list)
next = MIN(next, tick_add(res->last_resolution, resolv_resolution_timeout(res)));
resolvers->t->expire = next;
task_queue(resolvers->t);
}
/* Forges a DNS query. It needs the following information from the caller:
* - <query_id> : the DNS query id corresponding to this query
* - <query_type> : DNS_RTYPE_* request DNS record type (A, AAAA, ANY...)
* - <hostname_dn> : hostname in domain name format
* - <hostname_dn_len> : length of <hostname_dn>
*
* To store the query, the caller must pass a buffer <buf> and its size
* <bufsize>. It returns the number of written bytes in success, -1 if <buf> is
* too short.
*/
static int resolv_build_query(int query_id, int query_type, unsigned int accepted_payload_size,
char *hostname_dn, int hostname_dn_len, char *buf, int bufsize)
{
struct dns_header dns_hdr;
struct dns_question qinfo;
struct dns_additional_record edns;
char *p = buf;
if (sizeof(dns_hdr) + sizeof(qinfo) + sizeof(edns) + hostname_dn_len >= bufsize)
return -1;
memset(buf, 0, bufsize);
/* Set dns query headers */
dns_hdr.id = (unsigned short) htons(query_id);
dns_hdr.flags = htons(0x0100); /* qr=0, opcode=0, aa=0, tc=0, rd=1, ra=0, z=0, rcode=0 */
dns_hdr.qdcount = htons(1); /* 1 question */
dns_hdr.ancount = 0;
dns_hdr.nscount = 0;
dns_hdr.arcount = htons(1);
memcpy(p, &dns_hdr, sizeof(dns_hdr));
p += sizeof(dns_hdr);
/* Set up query hostname */
memcpy(p, hostname_dn, hostname_dn_len);
p += hostname_dn_len;
*p++ = 0;
/* Set up query info (type and class) */
qinfo.qtype = htons(query_type);
qinfo.qclass = htons(DNS_RCLASS_IN);
memcpy(p, &qinfo, sizeof(qinfo));
p += sizeof(qinfo);
/* Set the DNS extension */
edns.name = 0;
edns.type = htons(DNS_RTYPE_OPT);
edns.udp_payload_size = htons(accepted_payload_size);
edns.extension = 0;
edns.data_length = 0;
memcpy(p, &edns, sizeof(edns));
p += sizeof(edns);
return (p - buf);
}
/* Sends a DNS query to resolvers associated to a resolution. It returns 0 on
* success or -1 if trash buffer is not large enough to build a valid query.
*/
static int resolv_send_query(struct resolv_resolution *resolution)
{
struct resolvers *resolvers = resolution->resolvers;
struct dns_nameserver *ns;
int len;
/* Update resolution */
resolution->nb_queries = 0;
resolution->nb_responses = 0;
resolution->last_query = now_ms;
len = resolv_build_query(resolution->query_id, resolution->query_type,
resolvers->accepted_payload_size,
resolution->hostname_dn, resolution->hostname_dn_len,
trash.area, trash.size);
if (len < 0) {
send_log(NULL, LOG_NOTICE,
"can not build the query message for %s, in resolvers %s.\n",
resolution->hostname_dn, resolvers->id);
return -1;
}
list_for_each_entry(ns, &resolvers->nameservers, list) {
if (dns_send_nameserver(ns, trash.area, len) >= 0)
resolution->nb_queries++;
}
/* Push the resolution at the end of the active list */
LIST_DEL_INIT(&resolution->list);
LIST_APPEND(&resolvers->resolutions.curr, &resolution->list);
return 0;
}
/* Prepares and sends a DNS resolution. It returns 1 if the query was sent, 0 if
* skipped and -1 if an error occurred.
*/
static int
resolv_run_resolution(struct resolv_resolution *resolution)
{
struct resolvers *resolvers = resolution->resolvers;
int query_id, i;
/* Avoid sending requests for resolutions that don't yet have an
* hostname, ie resolutions linked to servers that do not yet have an
* fqdn */
if (!resolution->hostname_dn)
return 0;
/* Check if a resolution has already been started for this server return
* directly to avoid resolution pill up. */
if (resolution->step != RSLV_STEP_NONE)
return 0;
/* Generates a new query id. We try at most 100 times to find a free
* query id */
for (i = 0; i < 100; ++i) {
query_id = resolv_rnd16();
if (!eb32_lookup(&resolvers->query_ids, query_id))
break;
query_id = -1;
}
if (query_id == -1) {
send_log(NULL, LOG_NOTICE,
"could not generate a query id for %s, in resolvers %s.\n",
resolution->hostname_dn, resolvers->id);
return -1;
}
/* Update resolution parameters */
resolution->query_id = query_id;
resolution->qid.key = query_id;
resolution->step = RSLV_STEP_RUNNING;
resolution->query_type = resolution->prefered_query_type;
resolution->try = resolvers->resolve_retries;
eb32_insert(&resolvers->query_ids, &resolution->qid);
/* Send the DNS query */
resolution->try -= 1;
resolv_send_query(resolution);
return 1;
}
/* Performs a name resolution for the requester <req> */
void resolv_trigger_resolution(struct resolv_requester *req)
{
struct resolvers *resolvers;
struct resolv_resolution *res;
int exp;
if (!req || !req->resolution)
return;
res = req->resolution;
resolvers = res->resolvers;
enter_resolver_code();
/* The resolution must not be triggered yet. Use the cached response, if
* valid */
exp = tick_add(res->last_resolution, resolvers->hold.valid);
if (resolvers->t && (res->status != RSLV_STATUS_VALID ||
!tick_isset(res->last_resolution) || tick_is_expired(exp, now_ms))) {
/* If the resolution is not running and the requester is a
* server, reset the resolution timer to force a quick
* resolution.
*/
if (res->step == RSLV_STEP_NONE &&
(obj_type(req->owner) == OBJ_TYPE_SERVER ||
obj_type(req->owner) == OBJ_TYPE_SRVRQ))
res->last_resolution = TICK_ETERNITY;
task_wakeup(resolvers->t, TASK_WOKEN_OTHER);
}
leave_resolver_code();
}
/* Resets some resolution parameters to initial values and also delete the query
* ID from the resolver's tree.
*/
static void resolv_reset_resolution(struct resolv_resolution *resolution)
{
/* update resolution status */
resolution->step = RSLV_STEP_NONE;
resolution->try = 0;
resolution->last_resolution = now_ms;
resolution->nb_queries = 0;
resolution->nb_responses = 0;
resolution->query_type = resolution->prefered_query_type;
/* clean up query id */
eb32_delete(&resolution->qid);
resolution->query_id = 0;
resolution->qid.key = 0;
}
/* Returns the query id contained in a DNS response */
static inline unsigned short resolv_response_get_query_id(unsigned char *resp)
{
return resp[0] * 256 + resp[1];
}
/* Analyses, re-builds and copies the name <name> from the DNS response packet
* <buffer>. <name> must point to the 'data_len' information or pointer 'c0'
* for compressed data. The result is copied into <dest>, ensuring we don't
* overflow using <dest_len> Returns the number of bytes the caller can move
* forward. If 0 it means an error occurred while parsing the name. <offset> is
* the number of bytes the caller could move forward.
*/
int resolv_read_name(unsigned char *buffer, unsigned char *bufend,
unsigned char *name, char *destination, int dest_len,
int *offset, unsigned int depth)
{
int nb_bytes = 0, n = 0;
int label_len;
unsigned char *reader = name;
char *dest = destination;
while (1) {
if (reader >= bufend)
goto err;
/* Name compression is in use */
if ((*reader & 0xc0) == 0xc0) {
if (reader + 1 >= bufend)
goto err;
/* Must point BEFORE current position */
if ((buffer + reader[1]) > reader)
goto err;
if (depth++ > 100)
goto err;
n = resolv_read_name(buffer, bufend, buffer + (*reader & 0x3f)*256 + reader[1],
dest, dest_len - nb_bytes, offset, depth);
if (n == 0)
goto err;
dest += n;
nb_bytes += n;
goto out;
}
label_len = *reader;
if (label_len == 0)
goto out;
/* Check if:
* - we won't read outside the buffer
* - there is enough place in the destination
*/
if ((reader + label_len >= bufend) || (nb_bytes + label_len >= dest_len))
goto err;
/* +1 to take label len + label string */
label_len++;
memcpy(dest, reader, label_len);
dest += label_len;
nb_bytes += label_len;
reader += label_len;
}
out:
/* offset computation:
* parse from <name> until finding either NULL or a pointer "c0xx"
*/
reader = name;
*offset = 0;
while (reader < bufend) {
if ((reader[0] & 0xc0) == 0xc0) {
*offset += 2;
break;
}
else if (*reader == 0) {
*offset += 1;
break;
}
*offset += 1;
++reader;
}
return nb_bytes;
err:
return 0;
}
/* Reinitialize the list of aborted resolutions before calling certain
* functions relying on it. The list must be processed by calling
* leave_resolver_code() after operations.
*/
static void enter_resolver_code()
{
if (!recurse)
LIST_INIT(&death_row);
recurse++;
}
/* Add a resolution to the death_row. */
static void abort_resolution(struct resolv_resolution *res)
{
/* Remove the resolution from query_ids tree and from any resolvers list */
eb32_delete(&res->qid);
res->query_id = 0;
res->qid.key = 0;
LIST_DEL_INIT(&res->list);
LIST_APPEND(&death_row, &res->list);
}
/* This releases any aborted resolution found in the death row. It is mandatory
* to call enter_resolver_code() first before the function (or loop) that
* needs to defer deletions. Note that some of them are in relation via internal
* objects and might cause the deletion of other ones from the same list, so we
* must absolutely not use a list_for_each_entry_safe() nor any such thing here,
* and solely rely on each call to remove the first remaining list element.
*/
static void leave_resolver_code()
{
struct resolv_resolution *res;
recurse--;
if (recurse)
return;
while (!LIST_ISEMPTY(&death_row)) {
res = LIST_NEXT(&death_row, struct resolv_resolution *, list);
resolv_free_resolution(res);
}
/* make sure nobody tries to add anything without having initialized it */
death_row = (struct list){ };
}
/* Cleanup fqdn/port and address of a server attached to a SRV resolution. This
* happens when an SRV item is purged or when the server status is considered as
* obsolete.
*
* Must be called with the DNS lock held, and with the death_row already
* initialized via enter_resolver_code().
*/
static void resolv_srvrq_cleanup_srv(struct server *srv)
{
_resolv_unlink_resolution(srv->resolv_requester);
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
srvrq_update_srv_status(srv, 1);
ha_free(&srv->hostname);
ha_free(&srv->hostname_dn);
srv->hostname_dn_len = 0;
memset(&srv->addr, 0, sizeof(srv->addr));
srv->svc_port = 0;
srv->flags |= SRV_F_NO_RESOLUTION;
ebpt_delete(&srv->host_dn);
ha_free(&srv->host_dn.key);
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
LIST_DEL_INIT(&srv->srv_rec_item);
LIST_APPEND(&srv->srvrq->attached_servers, &srv->srv_rec_item);
srv->srvrq_check->expire = TICK_ETERNITY;
}
/* Takes care to cleanup a server resolution when it is outdated. This only
* happens for a server relying on a SRV record.
*/
static struct task *resolv_srvrq_expire_task(struct task *t, void *context, unsigned int state)
{
struct server *srv = context;
if (!tick_is_expired(t->expire, now_ms))
goto end;
enter_resolver_code();
HA_SPIN_LOCK(DNS_LOCK, &srv->srvrq->resolvers->lock);
resolv_srvrq_cleanup_srv(srv);
HA_SPIN_UNLOCK(DNS_LOCK, &srv->srvrq->resolvers->lock);
leave_resolver_code();
end:
return t;
}
/* Checks for any obsolete record, also identify any SRV request, and try to
* find a corresponding server.
*/
static void resolv_check_response(struct resolv_resolution *res)
{
struct resolvers *resolvers = res->resolvers;
struct resolv_requester *req;
struct eb32_node *eb32, *eb32_back;
struct server *srv, *srvback;
struct resolv_srvrq *srvrq;
for (eb32 = eb32_first(&res->response.answer_tree); eb32 && (eb32_back = eb32_next(eb32), 1); eb32 = eb32_back) {
struct resolv_answer_item *item = eb32_entry(eb32, typeof(*item), link);
struct resolv_answer_item *ar_item = item->ar_item;
/* clean up obsolete Additional record */
if (ar_item && tick_is_lt(tick_add(ar_item->last_seen, resolvers->hold.obsolete), now_ms)) {
/* Cleaning up the AR item will trigger an extra DNS resolution, except if the SRV
* item is also obsolete.
*/
pool_free(resolv_answer_item_pool, ar_item);
item->ar_item = NULL;
}
/* Remove obsolete items */
if (tick_is_lt(tick_add(item->last_seen, resolvers->hold.obsolete), now_ms)) {
if (item->type == DNS_RTYPE_A || item->type == DNS_RTYPE_AAAA) {
/* Remove any associated server */
list_for_each_entry_safe(srv, srvback, &item->attached_servers, ip_rec_item) {
LIST_DEL_INIT(&srv->ip_rec_item);
}
}
else if (item->type == DNS_RTYPE_SRV) {
/* Remove any associated server */
list_for_each_entry_safe(srv, srvback, &item->attached_servers, srv_rec_item)
resolv_srvrq_cleanup_srv(srv);
}
eb32_delete(&item->link);
if (item->ar_item) {
pool_free(resolv_answer_item_pool, item->ar_item);
item->ar_item = NULL;
}
pool_free(resolv_answer_item_pool, item);
continue;
}
if (item->type != DNS_RTYPE_SRV)
continue;
/* Now process SRV records */
list_for_each_entry(req, &res->requesters, list) {
struct ebpt_node *node;
char target[DNS_MAX_NAME_SIZE+1];
int i;
if ((srvrq = objt_resolv_srvrq(req->owner)) == NULL)
continue;
/* Check if a server already uses that record */
srv = NULL;
list_for_each_entry(srv, &item->attached_servers, srv_rec_item) {
if (srv->srvrq == srvrq) {
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
goto srv_found;
}
}
/* If not empty we try to match a server
* in server state file tree with the same hostname
*/
if (!eb_is_empty(&srvrq->named_servers)) {
srv = NULL;
/* convert the key to lookup in lower case */
for (i = 0 ; item->data.target[i] ; i++)
target[i] = tolower(item->data.target[i]);
target[i] = 0;
node = ebis_lookup(&srvrq->named_servers, target);
if (node) {
srv = ebpt_entry(node, struct server, host_dn);
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
/* an entry was found with the same hostname
* let check this node if the port matches
* and try next node if the hostname
* is still the same
*/
while (1) {
if (srv->svc_port == item->port) {
/* server found, we remove it from tree */
ebpt_delete(node);
ha_free(&srv->host_dn.key);
goto srv_found;
}
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
node = ebpt_next(node);
if (!node)
break;
srv = ebpt_entry(node, struct server, host_dn);
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
if ((item->data_len != srv->hostname_dn_len)
|| memcmp(srv->hostname_dn, item->data.target, item->data_len) != 0) {
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
break;
}
}
}
}
/* Pick the first server listed in srvrq (those ones don't
* have hostname and are free to use)
*/
srv = NULL;
list_for_each_entry(srv, &srvrq->attached_servers, srv_rec_item) {
LIST_DEL_INIT(&srv->srv_rec_item);
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
goto srv_found;
}
srv = NULL;
srv_found:
/* And update this server, if found (srv is locked here) */
if (srv) {
/* re-enable DNS resolution for this server by default */
srv->flags &= ~SRV_F_NO_RESOLUTION;
srv->srvrq_check->expire = TICK_ETERNITY;
srv->svc_port = item->port;
srv->flags &= ~SRV_F_MAPPORTS;
/* Check if an Additional Record is associated to this SRV record.
* Perform some sanity checks too to ensure the record can be used.
* If all fine, we simply pick up the IP address found and associate
* it to the server. And DNS resolution is disabled for this server.
*/
if ((item->ar_item != NULL) &&
(item->ar_item->type == DNS_RTYPE_A || item->ar_item->type == DNS_RTYPE_AAAA))
{
switch (item->ar_item->type) {
case DNS_RTYPE_A:
srv_update_addr(srv, &item->ar_item->data.in4.sin_addr, AF_INET, "DNS additional record");
break;
case DNS_RTYPE_AAAA:
srv_update_addr(srv, &item->ar_item->data.in6.sin6_addr, AF_INET6, "DNS additional record");
break;
}
srv->flags |= SRV_F_NO_RESOLUTION;
/* Unlink A/AAAA resolution for this server if there is an AR item.
* It is usless to perform an extra resolution
*/
_resolv_unlink_resolution(srv->resolv_requester);
}
if (!srv->hostname_dn) {
const char *msg = NULL;
char hostname[DNS_MAX_NAME_SIZE+1];
if (resolv_dn_label_to_str(item->data.target, item->data_len,
hostname, sizeof(hostname)) == -1) {
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
continue;
}
msg = srv_update_fqdn(srv, hostname, "SRV record", 1);
if (msg)
send_log(srv->proxy, LOG_NOTICE, "%s", msg);
}
if (!LIST_INLIST(&srv->srv_rec_item))
LIST_APPEND(&item->attached_servers, &srv->srv_rec_item);
if (!(srv->flags & SRV_F_NO_RESOLUTION)) {
/* If there is no AR item responsible of the FQDN resolution,
* trigger a dedicated DNS resolution
*/
if (!srv->resolv_requester || !srv->resolv_requester->resolution)
resolv_link_resolution(srv, OBJ_TYPE_SERVER, 1);
}
/* Update the server status */
srvrq_update_srv_status(srv, (srv->addr.ss_family != AF_INET && srv->addr.ss_family != AF_INET6));
if (!srv->resolv_opts.ignore_weight) {
char weight[9];
int ha_weight;
/* DNS weight range if from 0 to 65535
* HAProxy weight is from 0 to 256
* The rule below ensures that weight 0 is well respected
* while allowing a "mapping" from DNS weight into HAProxy's one.
*/
ha_weight = (item->weight + 255) / 256;
snprintf(weight, sizeof(weight), "%d", ha_weight);
server_parse_weight_change_request(srv, weight);
}
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
}
}
}
}
/* Validates that the buffer DNS response provided in <resp> and finishing
* before <bufend> is valid from a DNS protocol point of view.
*
* The result is stored in <resolution>' response, buf_response,
* response_query_records and response_answer_records members.
*
* This function returns one of the RSLV_RESP_* code to indicate the type of
* error found.
*/
static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufend,
struct resolv_resolution *resolution, int max_answer_records)
{
unsigned char *reader;
char *previous_dname, tmpname[DNS_MAX_NAME_SIZE];
int len, flags, offset;
int nb_saved_records;
struct resolv_query_item *query;
struct resolv_answer_item *answer_record, *tmp_record;
struct resolv_response *r_res;
struct eb32_node *eb32;
uint32_t key = 0;
int i, found = 0;
int cause = RSLV_RESP_ERROR;
reader = resp;
len = 0;
previous_dname = NULL;
query = NULL;
answer_record = NULL;
/* Initialization of response buffer and structure */
r_res = &resolution->response;
/* query id */
if (reader + 2 >= bufend)
goto invalid_resp;
r_res->header.id = reader[0] * 256 + reader[1];
reader += 2;
/* Flags and rcode are stored over 2 bytes
* First byte contains:
* - response flag (1 bit)
* - opcode (4 bits)
* - authoritative (1 bit)
* - truncated (1 bit)
* - recursion desired (1 bit)
*/
if (reader + 2 >= bufend)
goto invalid_resp;
flags = reader[0] * 256 + reader[1];
if ((flags & DNS_FLAG_REPLYCODE) != DNS_RCODE_NO_ERROR) {
if ((flags & DNS_FLAG_REPLYCODE) == DNS_RCODE_NX_DOMAIN) {
cause = RSLV_RESP_NX_DOMAIN;
goto return_error;
}
else if ((flags & DNS_FLAG_REPLYCODE) == DNS_RCODE_REFUSED) {
cause = RSLV_RESP_REFUSED;
goto return_error;
}
else {
cause = RSLV_RESP_ERROR;
goto return_error;
}
}
/* Move forward 2 bytes for flags */
reader += 2;
/* 2 bytes for question count */
if (reader + 2 >= bufend)
goto invalid_resp;
r_res->header.qdcount = reader[0] * 256 + reader[1];
/* (for now) we send one query only, so we expect only one in the
* response too */
if (r_res->header.qdcount != 1) {
cause = RSLV_RESP_QUERY_COUNT_ERROR;
goto return_error;
}
if (r_res->header.qdcount > DNS_MAX_QUERY_RECORDS)
goto invalid_resp;
reader += 2;
/* 2 bytes for answer count */
if (reader + 2 >= bufend)
goto invalid_resp;
r_res->header.ancount = reader[0] * 256 + reader[1];
if (r_res->header.ancount == 0) {
cause = RSLV_RESP_ANCOUNT_ZERO;
goto return_error;
}
/* Check if too many records are announced */
if (r_res->header.ancount > max_answer_records)
goto invalid_resp;
reader += 2;
/* 2 bytes authority count */
if (reader + 2 >= bufend)
goto invalid_resp;
r_res->header.nscount = reader[0] * 256 + reader[1];
reader += 2;
/* 2 bytes additional count */
if (reader + 2 >= bufend)
goto invalid_resp;
r_res->header.arcount = reader[0] * 256 + reader[1];
reader += 2;
/* Parsing dns queries. For now there is only one query and it exists
* because (qdcount == 1).
*/
query = &resolution->response_query_records[0];
/* Name is a NULL terminated string in our case, since we have
* one query per response and the first one can't be compressed
* (using the 0x0c format) */
offset = 0;
len = resolv_read_name(resp, bufend, reader, query->name, DNS_MAX_NAME_SIZE, &offset, 0);
if (len == 0)
goto invalid_resp;
/* Now let's check the query's dname corresponds to the one we sent. */
if (len != resolution->hostname_dn_len ||
memcmp(query->name, resolution->hostname_dn, resolution->hostname_dn_len) != 0) {
cause = RSLV_RESP_WRONG_NAME;
goto return_error;
}
reader += offset;
previous_dname = query->name;
/* move forward 2 bytes for question type */
if (reader + 2 >= bufend)
goto invalid_resp;
query->type = reader[0] * 256 + reader[1];
reader += 2;
/* move forward 2 bytes for question class */
if (reader + 2 >= bufend)
goto invalid_resp;
query->class = reader[0] * 256 + reader[1];
reader += 2;
/* TRUNCATED flag must be checked after we could read the query type
* because a TRUNCATED SRV query type response can still be exploited
*/
if (query->type != DNS_RTYPE_SRV && flags & DNS_FLAG_TRUNCATED) {
cause = RSLV_RESP_TRUNCATED;
goto return_error;
}
/* now parsing response records */
nb_saved_records = 0;
for (i = 0; i < r_res->header.ancount; i++) {
if (reader >= bufend)
goto invalid_resp;
answer_record = pool_alloc(resolv_answer_item_pool);
if (answer_record == NULL)
goto invalid_resp;
/* initialization */
answer_record->ar_item = NULL;
answer_record->last_seen = TICK_ETERNITY;
LIST_INIT(&answer_record->attached_servers);
answer_record->link.node.leaf_p = NULL;
offset = 0;
len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
if (len == 0)
goto invalid_resp;
/* Check if the current record dname is valid. previous_dname
* points either to queried dname or last CNAME target */
if (query->type != DNS_RTYPE_SRV && memcmp(previous_dname, tmpname, len) != 0) {
if (i == 0) {
/* First record, means a mismatch issue between
* queried dname and dname found in the first
* record */
goto invalid_resp;
}
else {
/* If not the first record, this means we have a
* CNAME resolution error.
*/
cause = RSLV_RESP_CNAME_ERROR;
goto return_error;
}
}
memcpy(answer_record->name, tmpname, len);
answer_record->name[len] = 0;
reader += offset;
if (reader >= bufend)
goto invalid_resp;
/* 2 bytes for record type (A, AAAA, CNAME, etc...) */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->type = reader[0] * 256 + reader[1];
reader += 2;
/* 2 bytes for class (2) */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->class = reader[0] * 256 + reader[1];
reader += 2;
/* 4 bytes for ttl (4) */
if (reader + 4 > bufend)
goto invalid_resp;
answer_record->ttl = reader[0] * 16777216 + reader[1] * 65536
+ reader[2] * 256 + reader[3];
reader += 4;
/* Now reading data len */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->data_len = reader[0] * 256 + reader[1];
/* Move forward 2 bytes for data len */
reader += 2;
if (reader + answer_record->data_len > bufend)
goto invalid_resp;
/* Analyzing record content */
switch (answer_record->type) {
case DNS_RTYPE_A:
/* ipv4 is stored on 4 bytes */
if (answer_record->data_len != 4)
goto invalid_resp;
answer_record->data.in4.sin_family = AF_INET;
memcpy(&answer_record->data.in4.sin_addr, reader, answer_record->data_len);
key = XXH32(reader, answer_record->data_len, answer_record->type);
break;
case DNS_RTYPE_CNAME:
/* Check if this is the last record and update the caller about the status:
* no IP could be found and last record was a CNAME. Could be triggered
* by a wrong query type
*
* + 1 because answer_record_id starts at 0
* while number of answers is an integer and
* starts at 1.
*/
if (i + 1 == r_res->header.ancount) {
cause = RSLV_RESP_CNAME_ERROR;
goto return_error;
}
offset = 0;
len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
if (len == 0)
goto invalid_resp;
memcpy(answer_record->data.target, tmpname, len);
answer_record->data.target[len] = 0;
key = XXH32(tmpname, len, answer_record->type);
previous_dname = answer_record->data.target;
break;
case DNS_RTYPE_SRV:
/* Answer must contain :
* - 2 bytes for the priority
* - 2 bytes for the weight
* - 2 bytes for the port
* - the target hostname
*/
if (answer_record->data_len <= 6)
goto invalid_resp;
answer_record->priority = read_n16(reader);
reader += sizeof(uint16_t);
answer_record->weight = read_n16(reader);
reader += sizeof(uint16_t);
answer_record->port = read_n16(reader);
reader += sizeof(uint16_t);
offset = 0;
len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
if (len == 0)
goto invalid_resp;
answer_record->data_len = len;
memcpy(answer_record->data.target, tmpname, len);
answer_record->data.target[len] = 0;
key = XXH32(tmpname, len, answer_record->type);
if (answer_record->ar_item != NULL) {
pool_free(resolv_answer_item_pool, answer_record->ar_item);
answer_record->ar_item = NULL;
}
break;
case DNS_RTYPE_AAAA:
/* ipv6 is stored on 16 bytes */
if (answer_record->data_len != 16)
goto invalid_resp;
answer_record->data.in6.sin6_family = AF_INET6;
memcpy(&answer_record->data.in6.sin6_addr, reader, answer_record->data_len);
key = XXH32(reader, answer_record->data_len, answer_record->type);
break;
} /* switch (record type) */
/* Increment the counter for number of records saved into our
* local response */
nb_saved_records++;
/* Move forward answer_record->data_len for analyzing next
* record in the response */
reader += ((answer_record->type == DNS_RTYPE_SRV)
? offset
: answer_record->data_len);
/* Lookup to see if we already had this entry */
found = 0;
for (eb32 = eb32_lookup(&r_res->answer_tree, key); eb32 != NULL; eb32 = eb32_next(eb32)) {
tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);
if (tmp_record->type != answer_record->type)
continue;
switch(tmp_record->type) {
case DNS_RTYPE_A:
if (!memcmp(&answer_record->data.in4.sin_addr,
&tmp_record->data.in4.sin_addr,
sizeof(answer_record->data.in4.sin_addr)))
found = 1;
break;
case DNS_RTYPE_AAAA:
if (!memcmp(&answer_record->data.in6.sin6_addr,
&tmp_record->data.in6.sin6_addr,
sizeof(answer_record->data.in6.sin6_addr)))
found = 1;
break;
case DNS_RTYPE_SRV:
if (answer_record->data_len == tmp_record->data_len &&
memcmp(answer_record->data.target, tmp_record->data.target, answer_record->data_len) == 0 &&
answer_record->port == tmp_record->port) {
tmp_record->weight = answer_record->weight;
found = 1;
}
break;
default:
break;
}
if (found == 1)
break;
}
if (found == 1) {
tmp_record->last_seen = now_ms;
pool_free(resolv_answer_item_pool, answer_record);
answer_record = NULL;
}
else {
answer_record->last_seen = now_ms;
answer_record->ar_item = NULL;
answer_record->link.key = key;
eb32_insert(&r_res->answer_tree, &answer_record->link);
answer_record = NULL;
}
} /* for i 0 to ancount */
/* Save the number of records we really own */
r_res->header.ancount = nb_saved_records;
/* now parsing additional records for SRV queries only */
if (query->type != DNS_RTYPE_SRV)
goto skip_parsing_additional_records;
/* if we find Authority records, just skip them */
for (i = 0; i < r_res->header.nscount; i++) {
offset = 0;
len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE,
&offset, 0);
if (len == 0)
continue;
if (reader + offset + 10 >= bufend)
goto invalid_resp;
reader += offset;
/* skip 2 bytes for class */
reader += 2;
/* skip 2 bytes for type */
reader += 2;
/* skip 4 bytes for ttl */
reader += 4;
/* read data len */
len = reader[0] * 256 + reader[1];
reader += 2;
if (reader + len >= bufend)
goto invalid_resp;
reader += len;
}
nb_saved_records = 0;
for (i = 0; i < r_res->header.arcount; i++) {
if (reader >= bufend)
goto invalid_resp;
answer_record = pool_alloc(resolv_answer_item_pool);
if (answer_record == NULL)
goto invalid_resp;
answer_record->last_seen = TICK_ETERNITY;
LIST_INIT(&answer_record->attached_servers);
offset = 0;
len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
if (len == 0) {
pool_free(resolv_answer_item_pool, answer_record);
answer_record = NULL;
continue;
}
memcpy(answer_record->name, tmpname, len);
answer_record->name[len] = 0;
reader += offset;
if (reader >= bufend)
goto invalid_resp;
/* 2 bytes for record type (A, AAAA, CNAME, etc...) */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->type = reader[0] * 256 + reader[1];
reader += 2;
/* 2 bytes for class (2) */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->class = reader[0] * 256 + reader[1];
reader += 2;
/* 4 bytes for ttl (4) */
if (reader + 4 > bufend)
goto invalid_resp;
answer_record->ttl = reader[0] * 16777216 + reader[1] * 65536
+ reader[2] * 256 + reader[3];
reader += 4;
/* Now reading data len */
if (reader + 2 > bufend)
goto invalid_resp;
answer_record->data_len = reader[0] * 256 + reader[1];
/* Move forward 2 bytes for data len */
reader += 2;
if (reader + answer_record->data_len > bufend)
goto invalid_resp;
/* Analyzing record content */
switch (answer_record->type) {
case DNS_RTYPE_A:
/* ipv4 is stored on 4 bytes */
if (answer_record->data_len != 4)
goto invalid_resp;
answer_record->data.in4.sin_family = AF_INET;
memcpy(&answer_record->data.in4.sin_addr, reader, answer_record->data_len);
break;
case DNS_RTYPE_AAAA:
/* ipv6 is stored on 16 bytes */
if (answer_record->data_len != 16)
goto invalid_resp;
answer_record->data.in6.sin6_family = AF_INET6;
memcpy(&answer_record->data.in6.sin6_addr, reader, answer_record->data_len);
break;
default:
pool_free(resolv_answer_item_pool, answer_record);
answer_record = NULL;
continue;
} /* switch (record type) */
/* Increment the counter for number of records saved into our
* local response */
nb_saved_records++;
/* Move forward answer_record->data_len for analyzing next
* record in the response */
reader += answer_record->data_len;
/* Lookup to see if we already had this entry */
found = 0;
for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL; eb32 = eb32_next(eb32)) {
struct resolv_answer_item *ar_item;
tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);
if (tmp_record->type != DNS_RTYPE_SRV || !tmp_record->ar_item)
continue;
ar_item = tmp_record->ar_item;
if (ar_item->type != answer_record->type || ar_item->last_seen == now_ms ||
len != tmp_record->data_len ||
memcmp(answer_record->name, tmp_record->data.target, tmp_record->data_len) != 0)
continue;
switch(ar_item->type) {
case DNS_RTYPE_A:
if (!memcmp(&answer_record->data.in4.sin_addr,
&ar_item->data.in4.sin_addr,
sizeof(answer_record->data.in4.sin_addr)))
found = 1;
break;
case DNS_RTYPE_AAAA:
if (!memcmp(&answer_record->data.in6.sin6_addr,
&ar_item->data.in6.sin6_addr,
sizeof(answer_record->data.in6.sin6_addr)))
found = 1;
break;
default:
break;
}
if (found == 1)
break;
}
if (found == 1) {
tmp_record->ar_item->last_seen = now_ms;
pool_free(resolv_answer_item_pool, answer_record);
answer_record = NULL;
}
else {
answer_record->last_seen = now_ms;
answer_record->ar_item = NULL;
// looking for the SRV record in the response list linked to this additional record
for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL; eb32 = eb32_next(eb32)) {
tmp_record = eb32_entry(eb32, typeof(*tmp_record), link);
if (tmp_record->type == DNS_RTYPE_SRV &&
tmp_record->ar_item == NULL &&
memcmp(tmp_record->data.target, answer_record->name, tmp_record->data_len) == 0) {
/* Always use the received additional record to refresh info */
if (tmp_record->ar_item)
pool_free(resolv_answer_item_pool, tmp_record->ar_item);
tmp_record->ar_item = answer_record;
answer_record = NULL;
break;
}
}
if (answer_record) {
pool_free(resolv_answer_item_pool, answer_record);
answer_record = NULL;
}
}
} /* for i 0 to arcount */
skip_parsing_additional_records:
/* Save the number of records we really own */
r_res->header.arcount = nb_saved_records;
resolv_check_response(resolution);
return RSLV_RESP_VALID;
invalid_resp:
cause = RSLV_RESP_INVALID;
return_error:
pool_free(resolv_answer_item_pool, answer_record);
return cause;
}
/* Searches dn_name resolution in resp.
* If existing IP not found, return the first IP matching family_priority,
* otherwise, first ip found
* The following tasks are the responsibility of the caller:
* - <r_res> contains an error free DNS response
* For both cases above, resolv_validate_dns_response is required
* returns one of the RSLV_UPD_* code
*/
int resolv_get_ip_from_response(struct resolv_response *r_res,
struct resolv_options *resolv_opts, void *currentip,
short currentip_sin_family,
void **newip, short *newip_sin_family,
struct server *owner)
{
struct resolv_answer_item *record, *found_record = NULL;
struct eb32_node *eb32;
int family_priority;
int currentip_found;
unsigned char *newip4, *newip6;
int currentip_sel;
int j;
int score, max_score;
int allowed_duplicated_ip;
/* srv is linked to an alive ip record */
if (owner && LIST_INLIST(&owner->ip_rec_item))
return RSLV_UPD_NO;
family_priority = resolv_opts->family_prio;
allowed_duplicated_ip = resolv_opts->accept_duplicate_ip;
*newip = newip4 = newip6 = NULL;
currentip_found = 0;
*newip_sin_family = AF_UNSPEC;
max_score = -1;
/* Select an IP regarding configuration preference.
* Top priority is the preferred network ip version,
* second priority is the preferred network.
* the last priority is the currently used IP,
*
* For these three priorities, a score is calculated. The
* weight are:
* 8 - preferred ip version.
* 4 - preferred network.
* 2 - if the ip in the record is not affected to any other server in the same backend (duplication)
* 1 - current ip.
* The result with the biggest score is returned.
*/
for (eb32 = eb32_first(&r_res->answer_tree); eb32 != NULL; eb32 = eb32_next(eb32)) {
void *ip;
unsigned char ip_type;
record = eb32_entry(eb32, typeof(*record), link);
if (record->type == DNS_RTYPE_A) {
ip_type = AF_INET;
ip = &record->data.in4.sin_addr;
}
else if (record->type == DNS_RTYPE_AAAA) {
ip_type = AF_INET6;
ip = &record->data.in6.sin6_addr;
}
else
continue;
score = 0;
/* Check for preferred ip protocol. */
if (ip_type == family_priority)
score += 8;
/* Check for preferred network. */
for (j = 0; j < resolv_opts->pref_net_nb; j++) {
/* Compare only the same addresses class. */
if (resolv_opts->pref_net[j].family != ip_type)
continue;
if ((ip_type == AF_INET &&
in_net_ipv4(ip,
&resolv_opts->pref_net[j].mask.in4,
&resolv_opts->pref_net[j].addr.in4)) ||
(ip_type == AF_INET6 &&
in_net_ipv6(ip,
&resolv_opts->pref_net[j].mask.in6,
&resolv_opts->pref_net[j].addr.in6))) {
score += 4;
break;
}
}
/* Check if the IP found in the record is already affected to a
* member of a group. If not, the score should be incremented
* by 2. */
if (owner) {
struct server *srv;
int already_used = 0;
list_for_each_entry(srv, &record->attached_servers, ip_rec_item) {
if (srv == owner)
continue;
if (srv->proxy == owner->proxy) {
already_used = 1;
break;
}
}
if (already_used) {
if (!allowed_duplicated_ip) {
continue;
}
}
else {
score += 2;
}
} else {
score += 2;
}
/* Check for current ip matching. */
if (ip_type == currentip_sin_family &&
((currentip_sin_family == AF_INET &&
!memcmp(ip, currentip, 4)) ||
(currentip_sin_family == AF_INET6 &&
!memcmp(ip, currentip, 16)))) {
score++;
currentip_sel = 1;
}
else
currentip_sel = 0;
/* Keep the address if the score is better than the previous
* score. The maximum score is 15, if this value is reached, we
* break the parsing. Implicitly, this score is reached the ip
* selected is the current ip. */
if (score > max_score) {
if (ip_type == AF_INET)
newip4 = ip;
else
newip6 = ip;
found_record = record;
currentip_found = currentip_sel;
if (score == 15) {
/* this was not registered on the current record but it matches
* let's fix it (it may comes from state file */
if (owner)
LIST_APPEND(&found_record->attached_servers, &owner->ip_rec_item);
return RSLV_UPD_NO;
}
max_score = score;
}
} /* list for each record entries */
/* No IP found in the response */
if (!newip4 && !newip6)
return RSLV_UPD_NO_IP_FOUND;
/* Case when the caller looks first for an IPv4 address */
if (family_priority == AF_INET) {
if (newip4) {
*newip = newip4;
*newip_sin_family = AF_INET;
}
else if (newip6) {
*newip = newip6;
*newip_sin_family = AF_INET6;
}
}
/* Case when the caller looks first for an IPv6 address */
else if (family_priority == AF_INET6) {
if (newip6) {
*newip = newip6;
*newip_sin_family = AF_INET6;
}
else if (newip4) {
*newip = newip4;
*newip_sin_family = AF_INET;
}
}
/* Case when the caller have no preference (we prefer IPv6) */
else if (family_priority == AF_UNSPEC) {
if (newip6) {
*newip = newip6;
*newip_sin_family = AF_INET6;
}
else if (newip4) {
*newip = newip4;
*newip_sin_family = AF_INET;
}
}
/* the ip of this record was chosen for the server */
if (owner && found_record) {
LIST_DEL_INIT(&owner->ip_rec_item);
LIST_APPEND(&found_record->attached_servers, &owner->ip_rec_item);
}
eb32 = eb32_first(&r_res->answer_tree);
if (eb32) {
/* Move the first record to the end of the list, for internal
* round robin.
*/
eb32_delete(eb32);
eb32_insert(&r_res->answer_tree, eb32);
}
return (currentip_found ? RSLV_UPD_NO : RSLV_UPD_SRVIP_NOT_FOUND);
}
/* Turns a domain name label into a string: 3www7haproxy3org into www.haproxy.org
*
* <dn> contains the input label of <dn_len> bytes long and does not need to be
* null-terminated. <str> must be allocated large enough to contain a full host
* name plus the trailing zero, and the allocated size must be passed in
* <str_len>.
*
* In case of error, -1 is returned, otherwise, the number of bytes copied in
* <str> (including the terminating null byte).
*/
int resolv_dn_label_to_str(const char *dn, int dn_len, char *str, int str_len)
{
char *ptr;
int i, sz;
if (str_len < dn_len)
return -1;
ptr = str;
for (i = 0; i < dn_len; ++i) {
sz = dn[i];
if (i)
*ptr++ = '.';
/* copy the string at i+1 to lower case */
for (; sz > 0; sz--)
*(ptr++) = tolower(dn[++i]);
}
*ptr++ = '\0';
return (ptr - str);
}
/* Turns a string into domain name label: www.haproxy.org into 3www7haproxy3org
*
* <str> contains the input string that is <str_len> bytes long (trailing zero
* not needed). <dn> buffer must be allocated large enough to contain the
* encoded string and a trailing zero, so it must be at least str_len+2, and
* this allocated buffer size must be passed in <dn_len>.
*
* In case of error, -1 is returned, otherwise, the number of bytes copied in
* <dn> (excluding the terminating null byte).
*/
int resolv_str_to_dn_label(const char *str, int str_len, char *dn, int dn_len)
{
int i, offset;
if (dn_len < str_len + 2)
return -1;
/* First byte of dn will be used to store the length of the first
* label */
offset = 0;
for (i = 0; i < str_len; ++i) {
if (str[i] == '.') {
/* 2 or more consecutive dots is invalid */
if (i == offset)
return -1;
/* ignore trailing dot */
if (i + 1 == str_len)
break;
dn[offset] = (i - offset);
offset = i+1;
continue;
}
dn[i+1] = tolower(str[i]);
}
dn[offset] = i - offset;
dn[i+1] = '\0';
return i+1;
}
/* Validates host name:
* - total size
* - each label size individually
* returns:
* 0 in case of error. If <err> is not NULL, an error message is stored there.
* 1 when no error. <err> is left unaffected.
*/
int resolv_hostname_validation(const char *string, char **err)
{
int i;
if (strlen(string) > DNS_MAX_NAME_SIZE) {
if (err)
*err = DNS_TOO_LONG_FQDN;
return 0;
}
while (*string) {
i = 0;
while (*string && *string != '.' && i < DNS_MAX_LABEL_SIZE) {
if (!(*string == '-' || *string == '_' ||
(*string >= 'a' && *string <= 'z') ||
(*string >= 'A' && *string <= 'Z') ||
(*string >= '0' && *string <= '9'))) {
if (err)
*err = DNS_INVALID_CHARACTER;
return 0;
}
i++;
string++;
}
if (!(*string))
break;
if (*string != '.' && i >= DNS_MAX_LABEL_SIZE) {
if (err)
*err = DNS_LABEL_TOO_LONG;
return 0;
}
string++;
}
return 1;
}
/* Picks up an available resolution from the different resolution list
* associated to a resolvers section, in this order:
* 1. check in resolutions.curr for the same hostname and query_type
* 2. check in resolutions.wait for the same hostname and query_type
* 3. Get a new resolution from resolution pool
*
* Returns an available resolution, NULL if none found.
*/
static struct resolv_resolution *resolv_pick_resolution(struct resolvers *resolvers,
char **hostname_dn, int hostname_dn_len,
int query_type)
{
struct resolv_resolution *res;
if (!*hostname_dn)
goto from_pool;
/* Search for same hostname and query type in resolutions.curr */
list_for_each_entry(res, &resolvers->resolutions.curr, list) {
if (!res->hostname_dn)
continue;
if ((query_type == res->prefered_query_type) &&
hostname_dn_len == res->hostname_dn_len &&
memcmp(*hostname_dn, res->hostname_dn, hostname_dn_len) == 0)
return res;
}
/* Search for same hostname and query type in resolutions.wait */
list_for_each_entry(res, &resolvers->resolutions.wait, list) {
if (!res->hostname_dn)
continue;
if ((query_type == res->prefered_query_type) &&
hostname_dn_len == res->hostname_dn_len &&
memcmp(*hostname_dn, res->hostname_dn, hostname_dn_len) == 0)
return res;
}
from_pool:
/* No resolution could be found, so let's allocate a new one */
res = pool_zalloc(resolv_resolution_pool);
if (res) {
res->resolvers = resolvers;
res->uuid = resolution_uuid;
res->status = RSLV_STATUS_NONE;
res->step = RSLV_STEP_NONE;
res->last_valid = now_ms;
LIST_INIT(&res->requesters);
res->response.answer_tree = EB_ROOT;
res->prefered_query_type = query_type;
res->query_type = query_type;
res->hostname_dn = *hostname_dn;
res->hostname_dn_len = hostname_dn_len;
++resolution_uuid;
/* Move the resolution to the resolvers wait queue */
LIST_APPEND(&resolvers->resolutions.wait, &res->list);
}
return res;
}
/* deletes and frees all answer_items from the resolution's answer_list */
static void resolv_purge_resolution_answer_records(struct resolv_resolution *resolution)
{
struct eb32_node *eb32, *eb32_back;
struct resolv_answer_item *item;
for (eb32 = eb32_first(&resolution->response.answer_tree);
eb32 && (eb32_back = eb32_next(eb32), 1);
eb32 = eb32_back) {
item = eb32_entry(eb32, typeof(*item), link);
eb32_delete(&item->link);
pool_free(resolv_answer_item_pool, item->ar_item);
pool_free(resolv_answer_item_pool, item);
}
}
/* Releases a resolution from its requester(s) and move it back to the pool */
static void resolv_free_resolution(struct resolv_resolution *resolution)
{
struct resolv_requester *req, *reqback;
/* clean up configuration */
resolv_reset_resolution(resolution);
resolution->hostname_dn = NULL;
resolution->hostname_dn_len = 0;
list_for_each_entry_safe(req, reqback, &resolution->requesters, list) {
LIST_DEL_INIT(&req->list);
req->resolution = NULL;
}
resolv_purge_resolution_answer_records(resolution);
LIST_DEL_INIT(&resolution->list);
pool_free(resolv_resolution_pool, resolution);
}
/* If *<req> is not NULL, returns it, otherwise tries to allocate a requester
* and makes it owned by this obj_type, with the proposed callback and error
* callback. On success, *req is assigned the allocated requester. Returns
* NULL on allocation failure.
*/
static struct resolv_requester *
resolv_get_requester(struct resolv_requester **req, enum obj_type *owner,
int (*cb)(struct resolv_requester *, struct dns_counters *),
int (*err_cb)(struct resolv_requester *, int))
{
struct resolv_requester *tmp;
if (*req)
return *req;
tmp = pool_alloc(resolv_requester_pool);
if (!tmp)
goto end;
LIST_INIT(&tmp->list);
tmp->owner = owner;
tmp->resolution = NULL;
tmp->requester_cb = cb;
tmp->requester_error_cb = err_cb;
*req = tmp;
end:
return tmp;
}
/* Links a requester (a server or a resolv_srvrq) with a resolution. It returns 0
* on success, -1 otherwise.
*/
int resolv_link_resolution(void *requester, int requester_type, int requester_locked)
{
struct resolv_resolution *res = NULL;
struct resolv_requester *req;
struct resolvers *resolvers;
struct server *srv = NULL;
struct resolv_srvrq *srvrq = NULL;
struct stream *stream = NULL;
char **hostname_dn;
int hostname_dn_len, query_type;
enter_resolver_code();
switch (requester_type) {
case OBJ_TYPE_SERVER:
srv = (struct server *)requester;
if (!requester_locked)
HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
req = resolv_get_requester(&srv->resolv_requester,
&srv->obj_type,
snr_resolution_cb,
snr_resolution_error_cb);
if (!requester_locked)
HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
if (!req)
goto err;
hostname_dn = &srv->hostname_dn;
hostname_dn_len = srv->hostname_dn_len;
resolvers = srv->resolvers;
query_type = ((srv->resolv_opts.family_prio == AF_INET)
? DNS_RTYPE_A
: DNS_RTYPE_AAAA);
break;
case OBJ_TYPE_SRVRQ:
srvrq = (struct resolv_srvrq *)requester;
req = resolv_get_requester(&srvrq->requester,
&srvrq->obj_type,
snr_resolution_cb,
srvrq_resolution_error_cb);
if (!req)
goto err;
hostname_dn = &srvrq->hostname_dn;
hostname_dn_len = srvrq->hostname_dn_len;
resolvers = srvrq->resolvers;
query_type = DNS_RTYPE_SRV;
break;
case OBJ_TYPE_STREAM:
stream = (struct stream *)requester;
req = resolv_get_requester(&stream->resolv_ctx.requester,
&stream->obj_type,
act_resolution_cb,
act_resolution_error_cb);
if (!req)
goto err;
hostname_dn = &stream->resolv_ctx.hostname_dn;
hostname_dn_len = stream->resolv_ctx.hostname_dn_len;
resolvers = stream->resolv_ctx.parent->arg.resolv.resolvers;
query_type = ((stream->resolv_ctx.parent->arg.resolv.opts->family_prio == AF_INET)
? DNS_RTYPE_A
: DNS_RTYPE_AAAA);
break;
default:
goto err;
}
/* Get a resolution from the resolvers' wait queue or pool */
if ((res = resolv_pick_resolution(resolvers, hostname_dn, hostname_dn_len, query_type)) == NULL)
goto err;
req->resolution = res;
LIST_APPEND(&res->requesters, &req->list);
leave_resolver_code();
return 0;
err:
if (res && LIST_ISEMPTY(&res->requesters))
resolv_free_resolution(res);
leave_resolver_code();
return -1;
}
/* This function removes all server/srvrq references on answer items. */
void resolv_detach_from_resolution_answer_items(struct resolv_resolution *res, struct resolv_requester *req)
{
struct eb32_node *eb32, *eb32_back;
struct resolv_answer_item *item;
struct server *srv, *srvback;
struct resolv_srvrq *srvrq;
enter_resolver_code();
if ((srv = objt_server(req->owner)) != NULL) {
LIST_DEL_INIT(&srv->ip_rec_item);
}
else if ((srvrq = objt_resolv_srvrq(req->owner)) != NULL) {
for (eb32 = eb32_first(&res->response.answer_tree);
eb32 && (eb32_back = eb32_next(eb32), 1);
eb32 = eb32_back) {
item = eb32_entry(eb32, typeof(*item), link);
if (item->type == DNS_RTYPE_SRV) {
list_for_each_entry_safe(srv, srvback, &item->attached_servers, srv_rec_item) {
if (srv->srvrq == srvrq)
resolv_srvrq_cleanup_srv(srv);
}
}
}
}
leave_resolver_code();
}
/* Removes a requester from a DNS resolution. It takes takes care of all the
* consequences. It also cleans up some parameters from the requester.
*/
static void _resolv_unlink_resolution(struct resolv_requester *requester)
{
struct resolv_resolution *res;
struct resolv_requester *req;
/* Nothing to do */
if (!requester || !requester->resolution)
return;
res = requester->resolution;
/* Clean up the requester */
LIST_DEL_INIT(&requester->list);
requester->resolution = NULL;
/* remove ref from the resolution answer item list to the requester */
resolv_detach_from_resolution_answer_items(res, requester);
/* We need to find another requester linked on this resolution */
if (!LIST_ISEMPTY(&res->requesters))
req = LIST_NEXT(&res->requesters, struct resolv_requester *, list);
else {
abort_resolution(res);
return;
}
/* Move hostname_dn related pointers to the next requester */
switch (obj_type(req->owner)) {
case OBJ_TYPE_SERVER:
res->hostname_dn = __objt_server(req->owner)->hostname_dn;
res->hostname_dn_len = __objt_server(req->owner)->hostname_dn_len;
break;
case OBJ_TYPE_SRVRQ:
res->hostname_dn = __objt_resolv_srvrq(req->owner)->hostname_dn;
res->hostname_dn_len = __objt_resolv_srvrq(req->owner)->hostname_dn_len;
break;
case OBJ_TYPE_STREAM:
res->hostname_dn = __objt_stream(req->owner)->resolv_ctx.hostname_dn;
res->hostname_dn_len = __objt_stream(req->owner)->resolv_ctx.hostname_dn_len;
break;
default:
res->hostname_dn = NULL;
res->hostname_dn_len = 0;
break;
}
}
/* The public version of the function above that deals with the death row. */
void resolv_unlink_resolution(struct resolv_requester *requester)
{
enter_resolver_code();
_resolv_unlink_resolution(requester);
leave_resolver_code();
}
/* Called when a network IO is generated on a name server socket for an incoming
* packet. It performs the following actions:
* - check if the packet requires processing (not outdated resolution)
* - ensure the DNS packet received is valid and call requester's callback
* - call requester's error callback if invalid response
* - check the dn_name in the packet against the one sent
*/
static int resolv_process_responses(struct dns_nameserver *ns)
{
struct dns_counters *tmpcounters;
struct resolvers *resolvers;
struct resolv_resolution *res;
unsigned char buf[DNS_MAX_UDP_MESSAGE + 1];
unsigned char *bufend;
int buflen, dns_resp;
int max_answer_records;
unsigned short query_id;
struct eb32_node *eb;
struct resolv_requester *req;
int keep_answer_items;
resolvers = ns->parent;
enter_resolver_code();
HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
/* process all pending input messages */
while (1) {
/* read message received */
memset(buf, '\0', resolvers->accepted_payload_size + 1);
if ((buflen = dns_recv_nameserver(ns, (void *)buf, sizeof(buf))) <= 0) {
break;
}
/* message too big */
if (buflen > resolvers->accepted_payload_size) {
ns->counters->app.resolver.too_big++;
continue;
}
/* initializing variables */
bufend = buf + buflen; /* pointer to mark the end of the buffer */
/* read the query id from the packet (16 bits) */
if (buf + 2 > bufend) {
ns->counters->app.resolver.invalid++;
continue;
}
query_id = resolv_response_get_query_id(buf);
/* search the query_id in the pending resolution tree */
eb = eb32_lookup(&resolvers->query_ids, query_id);
if (eb == NULL) {
/* unknown query id means an outdated response and can be safely ignored */
ns->counters->app.resolver.outdated++;
continue;
}
/* known query id means a resolution in progress */
res = eb32_entry(eb, struct resolv_resolution, qid);
/* number of responses received */
res->nb_responses++;
max_answer_records = (resolvers->accepted_payload_size - DNS_HEADER_SIZE) / DNS_MIN_RECORD_SIZE;
dns_resp = resolv_validate_dns_response(buf, bufend, res, max_answer_records);
switch (dns_resp) {
case RSLV_RESP_VALID:
break;
case RSLV_RESP_INVALID:
case RSLV_RESP_QUERY_COUNT_ERROR:
case RSLV_RESP_WRONG_NAME:
res->status = RSLV_STATUS_INVALID;
ns->counters->app.resolver.invalid++;
break;
case RSLV_RESP_NX_DOMAIN:
res->status = RSLV_STATUS_NX;
ns->counters->app.resolver.nx++;
break;
case RSLV_RESP_REFUSED:
res->status = RSLV_STATUS_REFUSED;
ns->counters->app.resolver.refused++;
break;
case RSLV_RESP_ANCOUNT_ZERO:
res->status = RSLV_STATUS_OTHER;
ns->counters->app.resolver.any_err++;
break;
case RSLV_RESP_CNAME_ERROR:
res->status = RSLV_STATUS_OTHER;
ns->counters->app.resolver.cname_error++;
break;
case RSLV_RESP_TRUNCATED:
res->status = RSLV_STATUS_OTHER;
ns->counters->app.resolver.truncated++;
break;
case RSLV_RESP_NO_EXPECTED_RECORD:
case RSLV_RESP_ERROR:
case RSLV_RESP_INTERNAL:
res->status = RSLV_STATUS_OTHER;
ns->counters->app.resolver.other++;
break;
}
/* Wait all nameservers response to handle errors */
if (dns_resp != RSLV_RESP_VALID && res->nb_responses < res->nb_queries)
continue;
/* Process error codes */
if (dns_resp != RSLV_RESP_VALID) {
if (res->prefered_query_type != res->query_type) {
/* The fallback on the query type was already performed,
* so check the try counter. If it falls to 0, we can
* report an error. Else, wait the next attempt. */
if (!res->try)
goto report_res_error;
}
else {
/* Fallback from A to AAAA or the opposite and re-send
* the resolution immediately. try counter is not
* decremented. */
if (res->prefered_query_type == DNS_RTYPE_A) {
res->query_type = DNS_RTYPE_AAAA;
resolv_send_query(res);
}
else if (res->prefered_query_type == DNS_RTYPE_AAAA) {
res->query_type = DNS_RTYPE_A;
resolv_send_query(res);
}
}
continue;
}
/* So the resolution succeeded */
res->status = RSLV_STATUS_VALID;
res->last_valid = now_ms;
ns->counters->app.resolver.valid++;
goto report_res_success;
report_res_error:
keep_answer_items = 0;
list_for_each_entry(req, &res->requesters, list)
keep_answer_items |= req->requester_error_cb(req, dns_resp);
if (!keep_answer_items)
resolv_purge_resolution_answer_records(res);
resolv_reset_resolution(res);
LIST_DEL_INIT(&res->list);
LIST_APPEND(&resolvers->resolutions.wait, &res->list);
continue;
report_res_success:
/* Only the 1rst requester s managed by the server, others are
* from the cache */
tmpcounters = ns->counters;
list_for_each_entry(req, &res->requesters, list) {
struct server *s = objt_server(req->owner);
if (s)
HA_SPIN_LOCK(SERVER_LOCK, &s->lock);
req->requester_cb(req, tmpcounters);
if (s)
HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);
tmpcounters = NULL;
}
resolv_reset_resolution(res);
LIST_DEL_INIT(&res->list);
LIST_APPEND(&resolvers->resolutions.wait, &res->list);
continue;
}
resolv_update_resolvers_timeout(resolvers);
HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
leave_resolver_code();
return buflen;
}
/* Processes DNS resolution. First, it checks the active list to detect expired
* resolutions and retry them if possible. Else a timeout is reported. Then, it
* checks the wait list to trigger new resolutions.
*/
struct task *process_resolvers(struct task *t, void *context, unsigned int state)
{
struct resolvers *resolvers = context;
struct resolv_resolution *res, *resback;
int exp;
enter_resolver_code();
HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
/* Handle all expired resolutions from the active list. Elements that
* need to be removed will in fact be moved to the death_row. Other
* ones will be handled normally.
*/
res = LIST_NEXT(&resolvers->resolutions.curr, struct resolv_resolution *, list);
while (&res->list != &resolvers->resolutions.curr) {
resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);
if (LIST_ISEMPTY(&res->requesters)) {
abort_resolution(res);
res = resback;
continue;
}
/* When we find the first resolution in the future, then we can
* stop here */
exp = tick_add(res->last_query, resolvers->timeout.retry);
if (!tick_is_expired(exp, now_ms))
break;
/* If current resolution has been tried too many times and
* finishes in timeout we update its status and remove it from
* the list */
if (!res->try) {
struct resolv_requester *req;
int keep_answer_items = 0;
/* Notify the result to the requesters */
if (!res->nb_responses)
res->status = RSLV_STATUS_TIMEOUT;
list_for_each_entry(req, &res->requesters, list)
keep_answer_items |= req->requester_error_cb(req, res->status);
if (!keep_answer_items)
resolv_purge_resolution_answer_records(res);
/* Clean up resolution info and remove it from the
* current list */
resolv_reset_resolution(res);
/* subsequent entries might have been deleted here */
resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);
LIST_DEL_INIT(&res->list);
LIST_APPEND(&resolvers->resolutions.wait, &res->list);
res = resback;
}
else {
/* Otherwise resend the DNS query and requeue the resolution */
if (!res->nb_responses || res->prefered_query_type != res->query_type) {
/* No response received (a real timeout) or fallback already done */
res->query_type = res->prefered_query_type;
res->try--;
}
else {
/* Fallback from A to AAAA or the opposite and re-send
* the resolution immediately. try counter is not
* decremented. */
if (res->prefered_query_type == DNS_RTYPE_A)
res->query_type = DNS_RTYPE_AAAA;
else if (res->prefered_query_type == DNS_RTYPE_AAAA)
res->query_type = DNS_RTYPE_A;
else
res->try--;
}
resolv_send_query(res);
resback = LIST_NEXT(&res->list, struct resolv_resolution *, list);
res = resback;
}
}
/* Handle all resolutions in the wait list */
list_for_each_entry_safe(res, resback, &resolvers->resolutions.wait, list) {
if (LIST_ISEMPTY(&res->requesters)) {
abort_resolution(res);
continue;
}
exp = tick_add(res->last_resolution, resolv_resolution_timeout(res));
if (tick_isset(res->last_resolution) && !tick_is_expired(exp, now_ms))
continue;
if (resolv_run_resolution(res) != 1) {
res->last_resolution = now_ms;
LIST_DEL_INIT(&res->list);
LIST_APPEND(&resolvers->resolutions.wait, &res->list);
}
}
resolv_update_resolvers_timeout(resolvers);
HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
/* now we can purge all queued deletions */
leave_resolver_code();
return t;
}
/* destroy a resolvers */
static void resolvers_destroy(struct resolvers *resolvers)
{
struct dns_nameserver *ns, *nsback;
struct resolv_resolution *res, *resback;
struct resolv_requester *req, *reqback;
list_for_each_entry_safe(ns, nsback, &resolvers->nameservers, list) {
free(ns->id);
free((char *)ns->conf.file);
if (ns->dgram) {
if (ns->dgram->conn.t.sock.fd != -1) {
fd_delete(ns->dgram->conn.t.sock.fd);
close(ns->dgram->conn.t.sock.fd);
}
if (ns->dgram->ring_req)
ring_free(ns->dgram->ring_req);
free(ns->dgram);
}
if (ns->stream) {
if (ns->stream->ring_req)
ring_free(ns->stream->ring_req);
if (ns->stream->task_req)
task_destroy(ns->stream->task_req);
if (ns->stream->task_rsp)
task_destroy(ns->stream->task_rsp);
free(ns->stream);
}
LIST_DEL_INIT(&ns->list);
EXTRA_COUNTERS_FREE(ns->extra_counters);
free(ns);
}
list_for_each_entry_safe(res, resback, &resolvers->resolutions.curr, list) {
list_for_each_entry_safe(req, reqback, &res->requesters, list) {
LIST_DEL_INIT(&req->list);
pool_free(resolv_requester_pool, req);
}
resolv_free_resolution(res);
}
list_for_each_entry_safe(res, resback, &resolvers->resolutions.wait, list) {
list_for_each_entry_safe(req, reqback, &res->requesters, list) {
LIST_DEL_INIT(&req->list);
pool_free(resolv_requester_pool, req);
}
resolv_free_resolution(res);
}
free_proxy(resolvers->px);
free(resolvers->id);
free((char *)resolvers->conf.file);
task_destroy(resolvers->t);
LIST_DEL_INIT(&resolvers->list);
free(resolvers);
}
/* Release memory allocated by DNS */
static void resolvers_deinit(void)
{
struct resolvers *resolvers, *resolversback;
struct resolv_srvrq *srvrq, *srvrqback;
list_for_each_entry_safe(resolvers, resolversback, &sec_resolvers, list) {
resolvers_destroy(resolvers);
}
list_for_each_entry_safe(srvrq, srvrqback, &resolv_srvrq_list, list) {
free(srvrq->name);
free(srvrq->hostname_dn);
LIST_DEL_INIT(&srvrq->list);
free(srvrq);
}
}
/* Finalizes the DNS configuration by allocating required resources and checking
* live parameters.
* Returns 0 on success, 1 on error.
*/
static int resolvers_finalize_config(void)
{
struct resolvers *resolvers;
struct proxy *px;
int err_code = 0;
enter_resolver_code();
/* allocate pool of resolution per resolvers */
list_for_each_entry(resolvers, &sec_resolvers, list) {
struct dns_nameserver *ns;
struct task *t;
/* Check if we can create the socket with nameservers info */
list_for_each_entry(ns, &resolvers->nameservers, list) {
int fd;
if (ns->dgram) {
/* Check nameserver info */
if ((fd = socket(ns->dgram->conn.addr.to.ss_family, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
ha_alert("resolvers '%s': can't create socket for nameserver '%s'.\n",
resolvers->id, ns->id);
err_code |= (ERR_ALERT|ERR_ABORT);
continue;
}
if (connect(fd, (struct sockaddr*)&ns->dgram->conn.addr.to, get_addr_len(&ns->dgram->conn.addr.to)) == -1) {
if (!resolvers->conf.implicit) { /* emit a warning only if it was configured manually */
ha_warning("resolvers '%s': can't connect socket for nameserver '%s'.\n",
resolvers->id, ns->id);
}
close(fd);
err_code |= ERR_WARN;
continue;
}
close(fd);
}
}
/* Create the task associated to the resolvers section */
if ((t = task_new_anywhere()) == NULL) {
ha_alert("resolvers '%s' : out of memory.\n", resolvers->id);
err_code |= (ERR_ALERT|ERR_ABORT);
goto err;
}
/* Update task's parameters */
t->process = process_resolvers;
t->context = resolvers;
resolvers->t = t;
task_wakeup(t, TASK_WOKEN_INIT);
}
for (px = proxies_list; px; px = px->next) {
struct server *srv;
if (px->flags & PR_FL_DISABLED) {
/* must not run and will not work anyway since
* nothing in the proxy is initialized.
*/
continue;
}
for (srv = px->srv; srv; srv = srv->next) {
struct resolvers *resolvers;
if (!srv->resolvers_id)
continue;
if ((resolvers = find_resolvers_by_id(srv->resolvers_id)) == NULL) {
ha_alert("%s '%s', server '%s': unable to find required resolvers '%s'\n",
proxy_type_str(px), px->id, srv->id, srv->resolvers_id);
err_code |= (ERR_ALERT|ERR_ABORT);
continue;
}
srv->resolvers = resolvers;
srv->srvrq_check = NULL;
if (srv->srvrq) {
if (!srv->srvrq->resolvers) {
srv->srvrq->resolvers = srv->resolvers;
if (resolv_link_resolution(srv->srvrq, OBJ_TYPE_SRVRQ, 0) == -1) {
ha_alert("%s '%s' : unable to set DNS resolution for server '%s'.\n",
proxy_type_str(px), px->id, srv->id);
err_code |= (ERR_ALERT|ERR_ABORT);
continue;
}
}
srv->srvrq_check = task_new_anywhere();
if (!srv->srvrq_check) {
ha_alert("%s '%s' : unable to create SRVRQ task for server '%s'.\n",
proxy_type_str(px), px->id, srv->id);
err_code |= (ERR_ALERT|ERR_ABORT);
goto err;
}
srv->srvrq_check->process = resolv_srvrq_expire_task;
srv->srvrq_check->context = srv;
srv->srvrq_check->expire = TICK_ETERNITY;
}
else if (resolv_link_resolution(srv, OBJ_TYPE_SERVER, 0) == -1) {
ha_alert("%s '%s', unable to set DNS resolution for server '%s'.\n",
proxy_type_str(px), px->id, srv->id);
err_code |= (ERR_ALERT|ERR_ABORT);
continue;
}
srv->flags |= SRV_F_NON_PURGEABLE;
}
}
if (err_code & (ERR_ALERT|ERR_ABORT))
goto err;
leave_resolver_code();
return 0;
err:
leave_resolver_code();
resolvers_deinit();
return 1;
}
static int stats_dump_resolv_to_buffer(struct stconn *sc,
struct dns_nameserver *ns,
struct field *stats, size_t stats_count,
struct list *stat_modules)
{
struct appctx *appctx = __sc_appctx(sc);
struct channel *rep = sc_ic(sc);
struct stats_module *mod;
size_t idx = 0;
memset(stats, 0, sizeof(struct field) * stats_count);
list_for_each_entry(mod, stat_modules, list) {
struct counters_node *counters = EXTRA_COUNTERS_GET(ns->extra_counters, mod);
mod->fill_stats(counters, stats + idx);
idx += mod->stats_count;
}
if (!stats_dump_one_line(stats, idx, appctx))
return 0;
if (!stats_putchk(rep, NULL, &trash))
goto full;
return 1;
full:
sc_have_room(sc);
return 0;
}
/* Uses <appctx.ctx.stats.obj1> as a pointer to the current resolver and <obj2>
* as a pointer to the current nameserver.
*/
int stats_dump_resolvers(struct stconn *sc,
struct field *stats, size_t stats_count,
struct list *stat_modules)
{
struct appctx *appctx = __sc_appctx(sc);
struct show_stat_ctx *ctx = appctx->svcctx;
struct channel *rep = sc_ic(sc);
struct resolvers *resolver = ctx->obj1;
struct dns_nameserver *ns = ctx->obj2;
if (!resolver)
resolver = LIST_NEXT(&sec_resolvers, struct resolvers *, list);
/* dump resolvers */
list_for_each_entry_from(resolver, &sec_resolvers, list) {
ctx->obj1 = resolver;
ns = ctx->obj2 ?
ctx->obj2 :
LIST_NEXT(&resolver->nameservers, struct dns_nameserver *, list);
list_for_each_entry_from(ns, &resolver->nameservers, list) {
ctx->obj2 = ns;
if (buffer_almost_full(&rep->buf))
goto full;
if (!stats_dump_resolv_to_buffer(sc, ns,
stats, stats_count,
stat_modules)) {
return 0;
}
}
ctx->obj2 = NULL;
}
return 1;
full:
sc_need_room(sc);
return 0;
}
void resolv_stats_clear_counters(int clrall, struct list *stat_modules)
{
struct resolvers *resolvers;
struct dns_nameserver *ns;
struct stats_module *mod;
void *counters;
list_for_each_entry(mod, stat_modules, list) {
if (!mod->clearable && !clrall)
continue;
list_for_each_entry(resolvers, &sec_resolvers, list) {
list_for_each_entry(ns, &resolvers->nameservers, list) {
counters = EXTRA_COUNTERS_GET(ns->extra_counters, mod);
memcpy(counters, mod->counters, mod->counters_size);
}
}
}
}
int resolv_allocate_counters(struct list *stat_modules)
{
struct stats_module *mod;
struct resolvers *resolvers;
struct dns_nameserver *ns;
list_for_each_entry(resolvers, &sec_resolvers, list) {
list_for_each_entry(ns, &resolvers->nameservers, list) {
EXTRA_COUNTERS_REGISTER(&ns->extra_counters, COUNTERS_RSLV,
alloc_failed);
list_for_each_entry(mod, stat_modules, list) {
EXTRA_COUNTERS_ADD(mod,
ns->extra_counters,
mod->counters,
mod->counters_size);
}
EXTRA_COUNTERS_ALLOC(ns->extra_counters, alloc_failed);
list_for_each_entry(mod, stat_modules, list) {
memcpy(ns->extra_counters->data + mod->counters_off[ns->extra_counters->type],
mod->counters, mod->counters_size);
/* Store the ns counters pointer */
if (strcmp(mod->name, "resolvers") == 0) {
ns->counters = (struct dns_counters *)ns->extra_counters->data + mod->counters_off[COUNTERS_RSLV];
ns->counters->id = ns->id;
ns->counters->pid = resolvers->id;
}
}
}
}
return 1;
alloc_failed:
return 0;
}
/* if an arg is found, it sets the optional resolvers section pointer into a
* show_resolvers_ctx struct pointed to by svcctx, or NULL when dumping all.
*/
static int cli_parse_stat_resolvers(char **args, char *payload, struct appctx *appctx, void *private)
{
struct show_resolvers_ctx *ctx = applet_reserve_svcctx(appctx, sizeof(*ctx));
struct resolvers *presolvers;
if (*args[2]) {
list_for_each_entry(presolvers, &sec_resolvers, list) {
if (strcmp(presolvers->id, args[2]) == 0) {
ctx->forced_section = presolvers;
break;
}
}
if (ctx->forced_section == NULL)
return cli_err(appctx, "Can't find that resolvers section\n");
}
return 0;
}
/* Dumps counters from all resolvers section and associated name servers. It
* returns 0 if the output buffer is full and it needs to be called again,
* otherwise non-zero. It may limit itself to the resolver pointed to by the
* <resolvers> field of struct show_resolvers_ctx pointed to by <svcctx> if
* it's not null.
*/
static int cli_io_handler_dump_resolvers_to_buffer(struct appctx *appctx)
{
struct show_resolvers_ctx *ctx = appctx->svcctx;
struct resolvers *resolvers = ctx->resolvers;
struct dns_nameserver *ns;
chunk_reset(&trash);
if (LIST_ISEMPTY(&sec_resolvers)) {
if (applet_putstr(appctx, "No resolvers found\n") == -1)
goto full;
}
else {
if (!resolvers)
resolvers = LIST_ELEM(sec_resolvers.n, typeof(resolvers), list);
list_for_each_entry_from(resolvers, &sec_resolvers, list) {
if (ctx->forced_section != NULL && ctx->forced_section != resolvers)
continue;
ctx->resolvers = resolvers;
ns = ctx->ns;
if (!ns) {
chunk_printf(&trash, "Resolvers section %s\n", resolvers->id);
if (applet_putchk(appctx, &trash) == -1)
goto full;
ns = LIST_ELEM(resolvers->nameservers.n, typeof(ns), list);
ctx->ns = ns;
}
list_for_each_entry_from(ns, &resolvers->nameservers, list) {
chunk_reset(&trash);
chunk_appendf(&trash, " nameserver %s:\n", ns->id);
chunk_appendf(&trash, " sent: %lld\n", ns->counters->sent);
chunk_appendf(&trash, " snd_error: %lld\n", ns->counters->snd_error);
chunk_appendf(&trash, " valid: %lld\n", ns->counters->app.resolver.valid);
chunk_appendf(&trash, " update: %lld\n", ns->counters->app.resolver.update);
chunk_appendf(&trash, " cname: %lld\n", ns->counters->app.resolver.cname);
chunk_appendf(&trash, " cname_error: %lld\n", ns->counters->app.resolver.cname_error);
chunk_appendf(&trash, " any_err: %lld\n", ns->counters->app.resolver.any_err);
chunk_appendf(&trash, " nx: %lld\n", ns->counters->app.resolver.nx);
chunk_appendf(&trash, " timeout: %lld\n", ns->counters->app.resolver.timeout);
chunk_appendf(&trash, " refused: %lld\n", ns->counters->app.resolver.refused);
chunk_appendf(&trash, " other: %lld\n", ns->counters->app.resolver.other);
chunk_appendf(&trash, " invalid: %lld\n", ns->counters->app.resolver.invalid);
chunk_appendf(&trash, " too_big: %lld\n", ns->counters->app.resolver.too_big);
chunk_appendf(&trash, " truncated: %lld\n", ns->counters->app.resolver.truncated);
chunk_appendf(&trash, " outdated: %lld\n", ns->counters->app.resolver.outdated);
if (applet_putchk(appctx, &trash) == -1)
goto full;
ctx->ns = ns;
}
ctx->ns = NULL;
/* was this the only section to dump ? */
if (ctx->forced_section)
break;
}
}
/* done! */
return 1;
full:
/* the output buffer is full, retry later */
return 0;
}
/* register cli keywords */
static struct cli_kw_list cli_kws = {{ }, {
{ { "show", "resolvers", NULL }, "show resolvers [id] : dumps counters from all resolvers section and associated name servers",
cli_parse_stat_resolvers, cli_io_handler_dump_resolvers_to_buffer },
{{},}
}
};
INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);
/*
* Prepare <rule> for hostname resolution.
* Returns -1 in case of any allocation failure, 0 if not.
* On error, a global failure counter is also incremented.
*/
static int action_prepare_for_resolution(struct stream *stream, const char *hostname, int hostname_len)
{
char *hostname_dn;
int hostname_dn_len;
struct buffer *tmp = get_trash_chunk();
if (!hostname)
return 0;
hostname_dn = tmp->area;
hostname_dn_len = resolv_str_to_dn_label(hostname, hostname_len,
hostname_dn, tmp->size);
if (hostname_dn_len == -1)
goto err;
stream->resolv_ctx.hostname_dn = strdup(hostname_dn);
stream->resolv_ctx.hostname_dn_len = hostname_dn_len;
if (!stream->resolv_ctx.hostname_dn)
goto err;
return 0;
err:
ha_free(&stream->resolv_ctx.hostname_dn);
resolv_failed_resolutions += 1;
return -1;
}
/*
* Execute the "do-resolution" action. May be called from {tcp,http}request.
*/
enum act_return resolv_action_do_resolve(struct act_rule *rule, struct proxy *px,
struct session *sess, struct stream *s, int flags)
{
struct resolv_resolution *resolution;
struct sample *smp;
struct resolv_requester *req;
struct resolvers *resolvers;
struct resolv_resolution *res;
int exp, locked = 0;
enum act_return ret = ACT_RET_CONT;
resolvers = rule->arg.resolv.resolvers;
enter_resolver_code();
/* we have a response to our DNS resolution */
use_cache:
if (s->resolv_ctx.requester && s->resolv_ctx.requester->resolution != NULL) {
resolution = s->resolv_ctx.requester->resolution;
if (!locked) {
HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
locked = 1;
}
if (resolution->step == RSLV_STEP_RUNNING)
goto yield;
if (resolution->step == RSLV_STEP_NONE) {
/* We update the variable only if we have a valid response. */
if (resolution->status == RSLV_STATUS_VALID) {
struct sample smp;
short ip_sin_family = 0;
void *ip = NULL;
resolv_get_ip_from_response(&resolution->response, rule->arg.resolv.opts, NULL,
0, &ip, &ip_sin_family, NULL);
switch (ip_sin_family) {
case AF_INET:
smp.data.type = SMP_T_IPV4;
memcpy(&smp.data.u.ipv4, ip, 4);
break;
case AF_INET6:
smp.data.type = SMP_T_IPV6;
memcpy(&smp.data.u.ipv6, ip, 16);
break;
default:
ip = NULL;
}
if (ip) {
smp.px = px;
smp.sess = sess;
smp.strm = s;
vars_set_by_name(rule->arg.resolv.varname, strlen(rule->arg.resolv.varname), &smp);
}
}
}
goto release_requester;
}
/* need to configure and start a new DNS resolution */
smp = sample_fetch_as_type(px, sess, s, SMP_OPT_DIR_REQ|SMP_OPT_FINAL, rule->arg.resolv.expr, SMP_T_STR);
if (smp == NULL)
goto end;
if (action_prepare_for_resolution(s, smp->data.u.str.area, smp->data.u.str.data) == -1)
goto end; /* on error, ignore the action */
s->resolv_ctx.parent = rule;
HA_SPIN_LOCK(DNS_LOCK, &resolvers->lock);
locked = 1;
resolv_link_resolution(s, OBJ_TYPE_STREAM, 0);
/* Check if there is a fresh enough response in the cache of our associated resolution */
req = s->resolv_ctx.requester;
if (!req || !req->resolution)
goto release_requester; /* on error, ignore the action */
res = req->resolution;
exp = tick_add(res->last_resolution, resolvers->hold.valid);
if (resolvers->t && res->status == RSLV_STATUS_VALID && tick_isset(res->last_resolution)
&& !tick_is_expired(exp, now_ms)) {
goto use_cache;
}
resolv_trigger_resolution(s->resolv_ctx.requester);
yield:
if (flags & ACT_OPT_FINAL)
goto release_requester;
ret = ACT_RET_YIELD;
end:
leave_resolver_code();
if (locked)
HA_SPIN_UNLOCK(DNS_LOCK, &resolvers->lock);
return ret;
release_requester:
ha_free(&s->resolv_ctx.hostname_dn);
s->resolv_ctx.hostname_dn_len = 0;
if (s->resolv_ctx.requester) {
_resolv_unlink_resolution(s->resolv_ctx.requester);
pool_free(resolv_requester_pool, s->resolv_ctx.requester);
s->resolv_ctx.requester = NULL;
}
goto end;
}
static void release_resolv_action(struct act_rule *rule)
{
release_sample_expr(rule->arg.resolv.expr);
free(rule->arg.resolv.varname);
free(rule->arg.resolv.resolvers_id);
free(rule->arg.resolv.opts);
}
/* parse "do-resolve" action
* This action takes the following arguments:
* do-resolve(<varName>,<resolversSectionName>,<resolvePrefer>) <expr>
*
* - <varName> is the variable name where the result of the DNS resolution will be stored
* (mandatory)
* - <resolversSectionName> is the name of the resolvers section to use to perform the resolution
* (mandatory)
* - <resolvePrefer> can be either 'ipv4' or 'ipv6' and is the IP family we would like to resolve first
* (optional), defaults to ipv6
* - <expr> is an HAProxy expression used to fetch the name to be resolved
*/
enum act_parse_ret resolv_parse_do_resolve(const char **args, int *orig_arg, struct proxy *px, struct act_rule *rule, char **err)
{
int cur_arg;
struct sample_expr *expr;
unsigned int where;
const char *beg, *end;
/* orig_arg points to the first argument, but we need to analyse the command itself first */
cur_arg = *orig_arg - 1;
/* locate varName, which is mandatory */
beg = strchr(args[cur_arg], '(');
if (beg == NULL)
goto do_resolve_parse_error;
beg = beg + 1; /* beg should points to the first character after opening parenthesis '(' */
end = strchr(beg, ',');
if (end == NULL)
goto do_resolve_parse_error;
rule->arg.resolv.varname = my_strndup(beg, end - beg);
if (rule->arg.resolv.varname == NULL)
goto do_resolve_parse_error;
/* locate resolversSectionName, which is mandatory.
* Since next parameters are optional, the delimiter may be comma ','
* or closing parenthesis ')'
*/
beg = end + 1;
end = strchr(beg, ',');
if (end == NULL)
end = strchr(beg, ')');
if (end == NULL)
goto do_resolve_parse_error;
rule->arg.resolv.resolvers_id = my_strndup(beg, end - beg);
if (rule->arg.resolv.resolvers_id == NULL)
goto do_resolve_parse_error;
rule->arg.resolv.opts = calloc(1, sizeof(*rule->arg.resolv.opts));
if (rule->arg.resolv.opts == NULL)
goto do_resolve_parse_error;
/* Default priority is ipv6 */
rule->arg.resolv.opts->family_prio = AF_INET6;
/* optional arguments accepted for now:
* ipv4 or ipv6
*/
while (*end != ')') {
beg = end + 1;
end = strchr(beg, ',');
if (end == NULL)
end = strchr(beg, ')');
if (end == NULL)
goto do_resolve_parse_error;
if (strncmp(beg, "ipv4", end - beg) == 0) {
rule->arg.resolv.opts->family_prio = AF_INET;
}
else if (strncmp(beg, "ipv6", end - beg) == 0) {
rule->arg.resolv.opts->family_prio = AF_INET6;
}
else {
goto do_resolve_parse_error;
}
}
cur_arg = cur_arg + 1;
expr = sample_parse_expr((char **)args, &cur_arg, px->conf.args.file, px->conf.args.line, err, &px->conf.args, NULL);
if (!expr)
goto do_resolve_parse_error;
where = 0;
if (px->cap & PR_CAP_FE)
where |= SMP_VAL_FE_HRQ_HDR;
if (px->cap & PR_CAP_BE)
where |= SMP_VAL_BE_HRQ_HDR;
if (!(expr->fetch->val & where)) {
memprintf(err,
"fetch method '%s' extracts information from '%s', none of which is available here",
args[cur_arg-1], sample_src_names(expr->fetch->use));
free(expr);
return ACT_RET_PRS_ERR;
}
rule->arg.resolv.expr = expr;
rule->action = ACT_CUSTOM;
rule->action_ptr = resolv_action_do_resolve;
*orig_arg = cur_arg;
rule->check_ptr = check_action_do_resolve;
rule->release_ptr = release_resolv_action;
return ACT_RET_PRS_OK;
do_resolve_parse_error:
ha_free(&rule->arg.resolv.varname);
ha_free(&rule->arg.resolv.resolvers_id);
memprintf(err, "Can't parse '%s'. Expects 'do-resolve(<varname>,<resolvers>[,<options>]) <expr>'. Available options are 'ipv4' and 'ipv6'",
args[cur_arg]);
return ACT_RET_PRS_ERR;
}
static struct action_kw_list http_req_kws = { { }, {
{ "do-resolve", resolv_parse_do_resolve, KWF_MATCH_PREFIX },
{ /* END */ }
}};
INITCALL1(STG_REGISTER, http_req_keywords_register, &http_req_kws);
static struct action_kw_list tcp_req_cont_actions = {ILH, {
{ "do-resolve", resolv_parse_do_resolve, KWF_MATCH_PREFIX },
{ /* END */ }
}};
INITCALL1(STG_REGISTER, tcp_req_cont_keywords_register, &tcp_req_cont_actions);
/* Check an "http-request do-resolve" action.
*
* The function returns 1 in success case, otherwise, it returns 0 and err is
* filled.
*/
int check_action_do_resolve(struct act_rule *rule, struct proxy *px, char **err)
{
struct resolvers *resolvers = NULL;
if (rule->arg.resolv.resolvers_id == NULL) {
memprintf(err,"Proxy '%s': %s", px->id, "do-resolve action without resolvers");
return 0;
}
resolvers = find_resolvers_by_id(rule->arg.resolv.resolvers_id);
if (resolvers == NULL) {
memprintf(err,"Can't find resolvers section '%s' for do-resolve action", rule->arg.resolv.resolvers_id);
return 0;
}
rule->arg.resolv.resolvers = resolvers;
return 1;
}
void resolvers_setup_proxy(struct proxy *px)
{
px->last_change = now.tv_sec;
px->cap = PR_CAP_FE | PR_CAP_BE;
px->maxconn = 0;
px->conn_retries = 1;
px->timeout.server = TICK_ETERNITY;
px->timeout.client = TICK_ETERNITY;
px->timeout.connect = TICK_ETERNITY;
px->accept = NULL;
px->options2 |= PR_O2_INDEPSTR | PR_O2_SMARTCON;
}
static int parse_resolve_conf(char **errmsg, char **warnmsg)
{
struct dns_nameserver *newnameserver = NULL;
const char *whitespace = "\r\n\t ";
char *resolv_line = NULL;
int resolv_linenum = 0;
FILE *f = NULL;
char *address = NULL;
struct sockaddr_storage *sk = NULL;
struct protocol *proto;
int duplicate_name = 0;
int err_code = 0;
if ((resolv_line = malloc(sizeof(*resolv_line) * LINESIZE)) == NULL) {
memprintf(errmsg, "out of memory.\n");
err_code |= ERR_ALERT | ERR_FATAL;
goto resolv_out;
}
if ((f = fopen("/etc/resolv.conf", "r")) == NULL) {
if (errmsg)
memprintf(errmsg, "failed to open /etc/resolv.conf.");
err_code |= ERR_ALERT | ERR_FATAL;
goto resolv_out;
}
sk = calloc(1, sizeof(*sk));
if (sk == NULL) {
if (errmsg)
memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
err_code |= ERR_ALERT | ERR_FATAL;
goto resolv_out;
}
while (fgets(resolv_line, LINESIZE, f) != NULL) {
resolv_linenum++;
if (strncmp(resolv_line, "nameserver", 10) != 0)
continue;
address = strtok(resolv_line + 10, whitespace);
if (address == resolv_line + 10)
continue;
if (address == NULL) {
if (warnmsg)
memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : nameserver line is missing address.\n",
*warnmsg ? *warnmsg : "", resolv_linenum);
err_code |= ERR_WARN;
continue;
}
duplicate_name = 0;
list_for_each_entry(newnameserver, &curr_resolvers->nameservers, list) {
if (strcmp(newnameserver->id, address) == 0) {
if (warnmsg)
memprintf(warnmsg, "%sParsing [/etc/resolv.conf:%d] : generated name for /etc/resolv.conf nameserver '%s' conflicts with another nameserver (declared at %s:%d), it appears to be a duplicate and will be excluded.\n",
*warnmsg ? *warnmsg : "", resolv_linenum, address, newnameserver->conf.file, newnameserver->conf.line);
err_code |= ERR_WARN;
duplicate_name = 1;
}
}
if (duplicate_name)
continue;
memset(sk, 0, sizeof(*sk));
if (!str2ip2(address, sk, 1)) {
if (warnmsg)
memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : address '%s' could not be recognized, nameserver will be excluded.\n",
*warnmsg ? *warnmsg : "", resolv_linenum, address);
err_code |= ERR_WARN;
continue;
}
set_host_port(sk, 53);
proto = protocol_lookup(sk->ss_family, PROTO_TYPE_STREAM, 0);
if (!proto || !proto->connect) {
if (warnmsg)
memprintf(warnmsg, "%sparsing [/etc/resolv.conf:%d] : '%s' : connect() not supported for this address family.\n",
*warnmsg ? *warnmsg : "", resolv_linenum, address);
err_code |= ERR_WARN;
continue;
}
if ((newnameserver = calloc(1, sizeof(*newnameserver))) == NULL) {
if (errmsg)
memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
err_code |= ERR_ALERT | ERR_FATAL;
goto resolv_out;
}
if (dns_dgram_init(newnameserver, sk) < 0) {
if (errmsg)
memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
err_code |= ERR_ALERT | ERR_FATAL;
free(newnameserver);
goto resolv_out;
}
newnameserver->conf.file = strdup("/etc/resolv.conf");
if (newnameserver->conf.file == NULL) {
if (errmsg)
memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
err_code |= ERR_ALERT | ERR_FATAL;
free(newnameserver);
goto resolv_out;
}
newnameserver->id = strdup(address);
if (newnameserver->id == NULL) {
if (errmsg)
memprintf(errmsg, "parsing [/etc/resolv.conf:%d] : out of memory.", resolv_linenum);
err_code |= ERR_ALERT | ERR_FATAL;
free((char *)newnameserver->conf.file);
free(newnameserver);
goto resolv_out;
}
newnameserver->parent = curr_resolvers;
newnameserver->process_responses = resolv_process_responses;
newnameserver->conf.line = resolv_linenum;
LIST_APPEND(&curr_resolvers->nameservers, &newnameserver->list);
}
resolv_out:
free(sk);
free(resolv_line);
if (f != NULL)
fclose(f);
return err_code;
}
static int resolvers_new(struct resolvers **resolvers, const char *id, const char *file, int linenum)
{
struct resolvers *r = NULL;
struct proxy *p = NULL;
int err_code = 0;
if ((r = calloc(1, sizeof(*r))) == NULL) {
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
/* allocate new proxy to tcp servers */
p = calloc(1, sizeof *p);
if (!p) {
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
init_new_proxy(p);
resolvers_setup_proxy(p);
p->parent = r;
p->id = strdup(id);
p->conf.args.file = p->conf.file = strdup(file);
p->conf.args.line = p->conf.line = linenum;
r->px = p;
/* default values */
LIST_APPEND(&sec_resolvers, &r->list);
r->conf.file = strdup(file);
r->conf.line = linenum;
r->id = strdup(id);
r->query_ids = EB_ROOT;
/* default maximum response size */
r->accepted_payload_size = 512;
/* default hold period for nx, other, refuse and timeout is 30s */
r->hold.nx = 30000;
r->hold.other = 30000;
r->hold.refused = 30000;
r->hold.timeout = 30000;
r->hold.obsolete = 0;
/* default hold period for valid is 10s */
r->hold.valid = 10000;
r->timeout.resolve = 1000;
r->timeout.retry = 1000;
r->resolve_retries = 3;
LIST_INIT(&r->nameservers);
LIST_INIT(&r->resolutions.curr);
LIST_INIT(&r->resolutions.wait);
HA_SPIN_INIT(&r->lock);
*resolvers = r;
out:
if (err_code & (ERR_FATAL|ERR_ABORT)) {
ha_free(&r);
ha_free(&p);
}
return err_code;
}
/*
* Parse a <resolvers> section.
* Returns the error code, 0 if OK, or any combination of :
* - ERR_ABORT: must abort ASAP
* - ERR_FATAL: we can continue parsing but not start the service
* - ERR_WARN: a warning has been emitted
* - ERR_ALERT: an alert has been emitted
* Only the two first ones can stop processing, the two others are just
* indicators.
*/
int cfg_parse_resolvers(const char *file, int linenum, char **args, int kwm)
{
const char *err;
int err_code = 0;
char *errmsg = NULL;
char *warnmsg = NULL;
if (strcmp(args[0], "resolvers") == 0) { /* new resolvers section */
if (!*args[1]) {
ha_alert("parsing [%s:%d] : missing name for resolvers section.\n", file, linenum);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
err = invalid_char(args[1]);
if (err) {
ha_alert("parsing [%s:%d] : character '%c' is not permitted in '%s' name '%s'.\n",
file, linenum, *err, args[0], args[1]);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
list_for_each_entry(curr_resolvers, &sec_resolvers, list) {
/* Error if two resolvers owns the same name */
if (strcmp(curr_resolvers->id, args[1]) == 0) {
ha_alert("Parsing [%s:%d]: resolvers '%s' has same name as another resolvers (declared at %s:%d).\n",
file, linenum, args[1], curr_resolvers->conf.file, curr_resolvers->conf.line);
err_code |= ERR_ALERT | ERR_ABORT;
}
}
err_code |= resolvers_new(&curr_resolvers, args[1], file, linenum);
if (err_code & ERR_ALERT) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
goto out;
}
}
else if (strcmp(args[0], "nameserver") == 0) { /* nameserver definition */
struct dns_nameserver *newnameserver = NULL;
struct sockaddr_storage *sk;
int port1, port2;
struct protocol *proto;
if (!*args[2]) {
ha_alert("parsing [%s:%d] : '%s' expects <name> and <addr>[:<port>] as arguments.\n",
file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
err = invalid_char(args[1]);
if (err) {
ha_alert("parsing [%s:%d] : character '%c' is not permitted in server name '%s'.\n",
file, linenum, *err, args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
list_for_each_entry(newnameserver, &curr_resolvers->nameservers, list) {
/* Error if two resolvers owns the same name */
if (strcmp(newnameserver->id, args[1]) == 0) {
ha_alert("Parsing [%s:%d]: nameserver '%s' has same name as another nameserver (declared at %s:%d).\n",
file, linenum, args[1], newnameserver->conf.file, newnameserver->conf.line);
err_code |= ERR_ALERT | ERR_FATAL;
}
}
sk = str2sa_range(args[2], NULL, &port1, &port2, NULL, &proto,
&errmsg, NULL, NULL, PA_O_RESOLVE | PA_O_PORT_OK | PA_O_PORT_MAND | PA_O_DGRAM | PA_O_STREAM | PA_O_DEFAULT_DGRAM);
if (!sk) {
ha_alert("parsing [%s:%d] : '%s %s' : %s\n", file, linenum, args[0], args[1], errmsg);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
if ((newnameserver = calloc(1, sizeof(*newnameserver))) == NULL) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
if (proto && proto->xprt_type == PROTO_TYPE_STREAM) {
err_code |= parse_server(file, linenum, args, curr_resolvers->px, NULL,
SRV_PARSE_PARSE_ADDR|SRV_PARSE_INITIAL_RESOLVE);
if (err_code & (ERR_FATAL|ERR_ABORT)) {
err_code |= ERR_ABORT;
goto out;
}
if (dns_stream_init(newnameserver, curr_resolvers->px->srv) < 0) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
err_code |= ERR_ALERT|ERR_ABORT;
goto out;
}
}
else if (dns_dgram_init(newnameserver, sk) < 0) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
if ((newnameserver->conf.file = strdup(file)) == NULL) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
if ((newnameserver->id = strdup(args[1])) == NULL) {
ha_alert("parsing [%s:%d] : out of memory.\n", file, linenum);
err_code |= ERR_ALERT | ERR_ABORT;
goto out;
}
newnameserver->parent = curr_resolvers;
newnameserver->process_responses = resolv_process_responses;
newnameserver->conf.line = linenum;
/* the nameservers are linked backward first */
LIST_APPEND(&curr_resolvers->nameservers, &newnameserver->list);
}
else if (strcmp(args[0], "parse-resolv-conf") == 0) {
err_code |= parse_resolve_conf(&errmsg, &warnmsg);
if (err_code & ERR_WARN) {
indent_msg(&warnmsg, 8);
ha_warning("parsing [%s:%d]: %s\n", file, linenum, warnmsg);
ha_free(&warnmsg);
}
if (err_code & ERR_ALERT) {
indent_msg(&errmsg, 8);
ha_alert("parsing [%s:%d]: %s\n", file, linenum, errmsg);
ha_free(&errmsg);
goto out;
}
}
else if (strcmp(args[0], "hold") == 0) { /* hold periods */
const char *res;
unsigned int time;
if (!*args[2]) {
ha_alert("parsing [%s:%d] : '%s' expects an <event> and a <time> as arguments.\n",
file, linenum, args[0]);
ha_alert("<event> can be either 'valid', 'nx', 'refused', 'timeout', or 'other'\n");
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
res = parse_time_err(args[2], &time, TIME_UNIT_MS);
if (res == PARSE_TIME_OVER) {
ha_alert("parsing [%s:%d]: timer overflow in argument <%s> to <%s>, maximum value is 2147483647 ms (~24.8 days).\n",
file, linenum, args[1], args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (res == PARSE_TIME_UNDER) {
ha_alert("parsing [%s:%d]: timer underflow in argument <%s> to <%s>, minimum non-null value is 1 ms.\n",
file, linenum, args[1], args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (res) {
ha_alert("parsing [%s:%d]: unexpected character '%c' in argument to <%s>.\n",
file, linenum, *res, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
if (strcmp(args[1], "nx") == 0)
curr_resolvers->hold.nx = time;
else if (strcmp(args[1], "other") == 0)
curr_resolvers->hold.other = time;
else if (strcmp(args[1], "refused") == 0)
curr_resolvers->hold.refused = time;
else if (strcmp(args[1], "timeout") == 0)
curr_resolvers->hold.timeout = time;
else if (strcmp(args[1], "valid") == 0)
curr_resolvers->hold.valid = time;
else if (strcmp(args[1], "obsolete") == 0)
curr_resolvers->hold.obsolete = time;
else {
ha_alert("parsing [%s:%d] : '%s' unknown <event>: '%s', expects either 'nx', 'timeout', 'valid', 'obsolete' or 'other'.\n",
file, linenum, args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
}
else if (strcmp(args[0], "accepted_payload_size") == 0) {
int i = 0;
if (!*args[1]) {
ha_alert("parsing [%s:%d] : '%s' expects <nb> as argument.\n",
file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
i = atoi(args[1]);
if (i < DNS_HEADER_SIZE || i > DNS_MAX_UDP_MESSAGE) {
ha_alert("parsing [%s:%d] : '%s' must be between %d and %d inclusive (was %s).\n",
file, linenum, args[0], DNS_HEADER_SIZE, DNS_MAX_UDP_MESSAGE, args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
curr_resolvers->accepted_payload_size = i;
}
else if (strcmp(args[0], "resolution_pool_size") == 0) {
ha_alert("parsing [%s:%d] : '%s' directive is not supported anymore (it never appeared in a stable release).\n",
file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (strcmp(args[0], "resolve_retries") == 0) {
if (!*args[1]) {
ha_alert("parsing [%s:%d] : '%s' expects <nb> as argument.\n",
file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
curr_resolvers->resolve_retries = atoi(args[1]);
}
else if (strcmp(args[0], "timeout") == 0) {
if (!*args[1]) {
ha_alert("parsing [%s:%d] : '%s' expects 'retry' or 'resolve' and <time> as arguments.\n",
file, linenum, args[0]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (strcmp(args[1], "retry") == 0 ||
strcmp(args[1], "resolve") == 0) {
const char *res;
unsigned int tout;
if (!*args[2]) {
ha_alert("parsing [%s:%d] : '%s %s' expects <time> as argument.\n",
file, linenum, args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
res = parse_time_err(args[2], &tout, TIME_UNIT_MS);
if (res == PARSE_TIME_OVER) {
ha_alert("parsing [%s:%d]: timer overflow in argument <%s> to <%s %s>, maximum value is 2147483647 ms (~24.8 days).\n",
file, linenum, args[2], args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (res == PARSE_TIME_UNDER) {
ha_alert("parsing [%s:%d]: timer underflow in argument <%s> to <%s %s>, minimum non-null value is 1 ms.\n",
file, linenum, args[2], args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
else if (res) {
ha_alert("parsing [%s:%d]: unexpected character '%c' in argument to <%s %s>.\n",
file, linenum, *res, args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
if (args[1][2] == 't')
curr_resolvers->timeout.retry = tout;
else
curr_resolvers->timeout.resolve = tout;
}
else {
ha_alert("parsing [%s:%d] : '%s' expects 'retry' or 'resolve' and <time> as arguments got '%s'.\n",
file, linenum, args[0], args[1]);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
}
else if (*args[0] != 0) {
ha_alert("parsing [%s:%d] : unknown keyword '%s' in '%s' section\n", file, linenum, args[0], cursection);
err_code |= ERR_ALERT | ERR_FATAL;
goto out;
}
out:
free(errmsg);
free(warnmsg);
return err_code;
}
/* try to create a "default" resolvers section which uses "/etc/resolv.conf"
*
* This function is opportunistic and does not try to display errors or warnings.
*/
int resolvers_create_default()
{
int err_code = 0;
if (global.mode & MODE_MWORKER_WAIT) /* does not create the section if in wait mode */
return 0;
/* if the section already exists, do nothing */
if (find_resolvers_by_id("default"))
return 0;
curr_resolvers = NULL;
err_code |= resolvers_new(&curr_resolvers, "default", "<internal>", 0);
if (err_code & ERR_CODE)
goto err;
curr_resolvers->conf.implicit = 1;
err_code |= parse_resolve_conf(NULL, NULL);
if (err_code & ERR_CODE)
goto err;
/* check if there was any nameserver in the resolvconf file */
if (LIST_ISEMPTY(&curr_resolvers->nameservers)) {
err_code |= ERR_FATAL;
goto err;
}
err:
if (err_code & ERR_CODE) {
resolvers_destroy(curr_resolvers);
curr_resolvers = NULL;
}
/* we never return an error there, we only try to create this section
* if that's possible */
return 0;
}
int cfg_post_parse_resolvers()
{
int err_code = 0;
struct server *srv;
if (curr_resolvers) {
/* prepare forward server descriptors */
if (curr_resolvers->px) {
srv = curr_resolvers->px->srv;
while (srv) {
/* init ssl if needed */
if (srv->use_ssl == 1 && xprt_get(XPRT_SSL) && xprt_get(XPRT_SSL)->prepare_srv) {
if (xprt_get(XPRT_SSL)->prepare_srv(srv)) {
ha_alert("unable to prepare SSL for server '%s' in resolvers section '%s'.\n", srv->id, curr_resolvers->id);
err_code |= ERR_ALERT | ERR_FATAL;
break;
}
}
srv = srv->next;
}
}
}
curr_resolvers = NULL;
return err_code;
}
REGISTER_CONFIG_SECTION("resolvers", cfg_parse_resolvers, cfg_post_parse_resolvers);
REGISTER_POST_DEINIT(resolvers_deinit);
REGISTER_CONFIG_POSTPARSER("dns runtime resolver", resolvers_finalize_config);
REGISTER_PRE_CHECK(resolvers_create_default);