MINOR: dns: Implement `parse-resolv-conf` directive
This introduces a new directive for the `resolvers` section:
`parse-resolv-conf`. When present, it will attempt to add any
nameservers in `/etc/resolv.conf` to the list of nameservers
for the current `resolvers` section.
[Mailing list thread][1].
[1]: https://www.mail-archive.com/haproxy@formilux.org/msg29600.html
diff --git a/doc/configuration.txt b/doc/configuration.txt
index e27d666..e901d7e 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -12042,6 +12042,11 @@
<ip> : IP address of the server
<port> : port where the DNS service actually runs
+parse-resolv-conf
+ Adds all nameservers found in /etc/resolv.conf to this resolvers nameservers
+ list. Ordered as if each nameserver in /etc/resolv.conf was individually
+ placed in the resolvers section in place of this directive.
+
hold <status> <period>
Defines <period> during which the last name resolution should be kept based
on last resolution <status>
@@ -12085,6 +12090,7 @@
resolvers mydns
nameserver dns1 10.0.0.1:53
nameserver dns2 10.0.0.2:53
+ parse-resolv-conf
resolve_retries 3
timeout resolve 1s
timeout retry 1s
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 3d224b9..f3c2be4 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -2256,7 +2256,7 @@
/* 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], curr_resolvers->conf.file, curr_resolvers->conf.line);
+ file, linenum, args[1], newnameserver->conf.file, newnameserver->conf.line);
err_code |= ERR_ALERT | ERR_FATAL;
}
}
@@ -2305,6 +2305,119 @@
newnameserver->addr = *sk;
}
+ else if (strcmp(args[0], "parse-resolv-conf") == 0) {
+ 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;
+
+ if ((resolv_line = malloc(sizeof(*resolv_line) * LINESIZE)) == NULL) {
+ ha_alert("parsing [%s:%d] : out of memory.\n",
+ file, linenum);
+ err_code |= ERR_ALERT | ERR_FATAL;
+ goto resolv_out;
+ }
+
+ if ((f = fopen("/etc/resolv.conf", "r")) == NULL) {
+ ha_alert("parsing [%s:%d] : failed to open /etc/resolv.conf.\n",
+ file, linenum);
+ err_code |= ERR_ALERT | ERR_FATAL;
+ goto resolv_out;
+ }
+
+ sk = calloc(1, sizeof(*sk));
+ if (sk == NULL) {
+ ha_alert("parsing [/etc/resolv.conf:%d] : out of memory.\n",
+ 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) {
+ ha_warning("parsing [/etc/resolv.conf:%d] : nameserver line is missing address.\n",
+ 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) {
+ ha_warning("Parsing [/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",
+ 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));
+ sk = str2ip2(address, sk, 1);
+ if (!sk) {
+ ha_warning("parsing [/etc/resolv.conf:%d] : address '%s' could not be recognized, namerserver will be excluded.\n",
+ resolv_linenum, address);
+ err_code |= ERR_WARN;
+ continue;
+ }
+
+ set_host_port(sk, 53);
+
+ proto = protocol_by_family(sk->ss_family);
+ if (!proto || !proto->connect) {
+ ha_warning("parsing [/etc/resolv.conf:%d] : '%s' : connect() not supported for this address family.\n",
+ resolv_linenum, address);
+ err_code |= ERR_WARN;
+ continue;
+ }
+
+ if ((newnameserver = calloc(1, sizeof(*newnameserver))) == NULL) {
+ ha_alert("parsing [/etc/resolv.conf:%d] : out of memory.\n", resolv_linenum);
+ err_code |= ERR_ALERT | ERR_FATAL;
+ goto resolv_out;
+ }
+
+ newnameserver->conf.file = strdup("/etc/resolv.conf");
+ if (newnameserver->conf.file == NULL) {
+ ha_alert("parsing [/etc/resolv.conf:%d] : out of memory.\n", resolv_linenum);
+ err_code |= ERR_ALERT | ERR_FATAL;
+ goto resolv_out;
+ }
+
+ newnameserver->id = strdup(address);
+ if (newnameserver->id == NULL) {
+ ha_alert("parsing [/etc/resolv.conf:%d] : out of memory.\n", resolv_linenum);
+ err_code |= ERR_ALERT | ERR_FATAL;
+ goto resolv_out;
+ }
+
+ newnameserver->resolvers = curr_resolvers;
+ newnameserver->conf.line = resolv_linenum;
+ newnameserver->addr = *sk;
+
+ LIST_ADDQ(&curr_resolvers->nameservers, &newnameserver->list);
+ }
+
+resolv_out:
+ free(sk);
+ free(resolv_line);
+ if (f != NULL)
+ fclose(f);
+ }
else if (strcmp(args[0], "hold") == 0) { /* hold periods */
const char *res;
unsigned int time;