Add support for async DNS

1 files changed, 143 insertions, 31 deletions

diff --git a/cfgdir.c b/cfgdir.c
index 436fe13..d6c48e1 100644
--- a/cfgdir.c
+++ b/cfgdir.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <ctype.h>
 #include <string.h>
@@ -5,9 +6,6 @@
 #include <sys/inotify.h>
 #include <dirent.h>
 #include <errno.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <netdb.h>
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <inttypes.h>
@@ -18,6 +16,98 @@
 #include "config.h"
 #include "server.h"
 
+static void
+scfg_dns_cb(struct dns_async *dns, bool (*server_cb)(struct cfg *, struct server *, struct saddr *))
+{
+	struct server *scfg;
+	struct cfg *cfg;
+	struct sockaddr_in *in4;
+	struct sockaddr_in6 *in6;
+	struct saddr *saddr;
+	struct addrinfo *results = NULL, *ai;
+	int r;
+
+	if (!dns || !dns->priv || !server_cb) {
+		error("invalid arguments\n");
+		return;
+	}
+
+	scfg = dns->priv;
+	cfg = scfg->cfg;
+
+	debug(DBG_DNS, "called, dns: %p, name: %s, scfg: %p, scfg->name: %s\n",
+	      dns, dns->name, scfg, scfg->name);
+
+	r = gai_error(&dns->gcb);
+	if (r == EAI_INPROGRESS) {
+		/* This shouldn't happen, assume we'll get called again */
+		error("called with request in progress\n");
+		return;
+	} else if (r == EAI_CANCELED) {
+		/* The server must be in the process of going away */
+		goto out;
+	} else if (r < 0) {
+		error("DNS lookup of %s:%s failed: %s\n",
+		      dns->name, dns->port, gai_strerror(r));
+		goto out;
+	}
+
+	results = dns->gcb.ar_result;
+
+	for (ai = results; ai; ai = ai->ai_next) {
+		saddr = zmalloc(sizeof(*saddr));
+		if (!saddr) {
+			error("DNS lookup of %s:%s failed: %m\n", dns->name, dns->port);
+			goto out;
+		}
+
+		switch (ai->ai_family) {
+		case AF_INET:
+			in4 = (struct sockaddr_in *)ai->ai_addr;
+			saddr_set_ipv4(saddr, in4->sin_addr.s_addr, in4->sin_port);
+			server_cb(cfg, scfg, saddr);
+			break;
+
+		case AF_INET6:
+			in6 = (struct sockaddr_in6 *)ai->ai_addr;
+			saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
+			server_cb(cfg, scfg, saddr);
+			break;
+
+		default:
+			error("getaddrinfo(%s:%s): unknown address family (%i)\n",
+			      dns->name, dns->port, ai->ai_family);
+			xfree(saddr);
+			break;
+		}
+	}
+
+out:
+	freeaddrinfo(results);
+	list_del(&dns->list);
+	xfree(dns);
+	uring_task_put(cfg, &scfg->task);
+	server_commit(cfg, scfg);
+}
+
+static void
+scfg_local_dns_cb(struct dns_async *dns)
+{
+	scfg_dns_cb(dns, server_add_local);
+}
+
+static void
+scfg_remote_dns_cb(struct dns_async *dns)
+{
+	scfg_dns_cb(dns, server_add_remote);
+}
+
+static void
+scfg_rcon_dns_cb(struct dns_async *dns)
+{
+	scfg_dns_cb(dns, server_add_rcon);
+}
+
 enum scfg_keys {
 	SCFG_KEY_INVALID = 0,
 	SCFG_KEY_TYPE,
@@ -51,11 +141,11 @@ struct cfg_key_value_map scfg_key_map[] = {
 	}, {
 		.key_name = "local",
 		.key_value = SCFG_KEY_LOCAL,
-		.value_type = CFG_VAL_TYPE_ADDRS,
+		.value_type = CFG_VAL_TYPE_ASYNC_ADDRS,
 	}, {
 		.key_name = "remote",
 		.key_value = SCFG_KEY_REMOTE,
-		.value_type = CFG_VAL_TYPE_ADDRS,
+		.value_type = CFG_VAL_TYPE_ASYNC_ADDRS,
 	}, {
 		.key_name = "idle_timeout",
 		.key_value = SCFG_KEY_IDLE_TIMEOUT,
@@ -79,7 +169,7 @@ struct cfg_key_value_map scfg_key_map[] = {
 	}, {
 		.key_name = "rcon",
 		.key_value = SCFG_KEY_RCON,
-		.value_type = CFG_VAL_TYPE_ADDRS,
+		.value_type = CFG_VAL_TYPE_ASYNC_ADDRS,
 	}, {
 		.key_name = "rcon_password",
 		.key_value = SCFG_KEY_RCON_PASSWORD,
@@ -95,6 +185,40 @@ struct cfg_key_value_map scfg_key_map[] = {
 	}
 };
 
+static bool
+handle_dns(struct cfg *cfg, struct server *scfg, const char *type,
+	   struct cfg_value *value, dns_callback_t *async_cb,
+	   bool (*sync_cb)(struct cfg *, struct server *, struct saddr *))
+{
+	struct saddr *saddr, *tmp;
+	struct dns_async *dns;
+
+	switch (value->type) {
+	case CFG_VAL_TYPE_ADDRS:
+		debug(DBG_DNS, "%s: got immediate addrs\n", type);
+
+		list_for_each_entry_safe(saddr, tmp, &value->saddrs, list) {
+			list_del(&saddr->list);
+			sync_cb(cfg, scfg, saddr);
+		}
+		return true;
+
+	case CFG_VAL_TYPE_ASYNC_ADDRS:
+		debug(DBG_DNS, "%s: doing async lookup of DNS record: %p\n",
+		      type, value->dns_async);
+
+		dns = value->dns_async;
+		dns->callback = async_cb;
+		dns->priv = scfg;
+		list_add(&dns->list, &scfg->dnslookups);
+		uring_task_get(cfg, &scfg->task);
+		return true;
+
+	default:
+		return false;
+	}
+}
+
 static void
 scfg_parse(struct cfg *cfg, struct server *scfg)
 {
@@ -106,7 +230,7 @@ scfg_parse(struct cfg *cfg, struct server *scfg)
 	while (true) {
 		int key;
 		const char *keyname;
-		union cfg_value value;
+		struct cfg_value value;
 
 		if (!config_parse_line(cfg, scfg->name, &pos, scfg_key_map,
 				       &key, &keyname, &value))
@@ -139,25 +263,17 @@ scfg_parse(struct cfg *cfg, struct server *scfg)
 				return;
 			break;
 
-		case SCFG_KEY_LOCAL: {
-			struct saddr *saddr, *tmp;
-
-			list_for_each_entry_safe(saddr, tmp, &value.saddrs, list) {
-				list_del(&saddr->list);
-				server_add_local(cfg, scfg, saddr);
-			}
+		case SCFG_KEY_LOCAL:
+			if (!handle_dns(cfg, scfg, "local", &value,
+					scfg_local_dns_cb, server_add_local))
+				return;
 			break;
-		}
-
-		case SCFG_KEY_REMOTE: {
-			struct saddr *saddr, *tmp;
 
-			list_for_each_entry_safe(saddr, tmp, &value.saddrs, list) {
-				list_del(&saddr->list);
-				server_add_remote(cfg, scfg, saddr);
-			}
+		case SCFG_KEY_REMOTE:
+			if (!handle_dns(cfg, scfg, "remote", &value,
+					scfg_remote_dns_cb, server_add_remote))
+				return;
 			break;
-		}
 
 		case SCFG_KEY_IDLE_TIMEOUT:
 			if (!server_set_idle_timeout(cfg, scfg, value.uint16))
@@ -197,15 +313,11 @@ scfg_parse(struct cfg *cfg, struct server *scfg)
 				return;
 			break;
 
-		case SCFG_KEY_RCON: {
-			struct saddr *saddr, *tmp;
-
-			list_for_each_entry_safe(saddr, tmp, &value.saddrs, list) {
-				list_del(&saddr->list);
-				server_add_rcon(cfg, scfg, saddr);
-			}
+		case SCFG_KEY_RCON:
+			if (!handle_dns(cfg, scfg, "rcon", &value,
+					scfg_rcon_dns_cb, server_add_rcon))
+				return;
 			break;
-		}
 
 		case SCFG_KEY_RCON_PASSWORD:
 			if (!server_set_rcon_password(cfg, scfg, value.str))