Add support for async DNS

1 files changed, 189 insertions, 78 deletions

diff --git a/config.c b/config.c
index aece8b1..199ba0b 100644
--- a/config.c
+++ b/config.c
@@ -1,11 +1,9 @@
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <ctype.h>
 #include <string.h>
 #include <stdbool.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>
@@ -22,7 +20,7 @@ eat_whitespace_and_comments(char **pos)
 		while (isspace(**pos))
 			(*pos)++;
 
-		if (**pos != '#') {
+		if (**pos != '#')
 			return;
 
 		while (**pos != '\r' && **pos != '\n' && **pos != '\0')
@@ -60,15 +58,119 @@ get_line(char **pos)
 }
 
 static bool
-strtosockaddrs(const char *str, struct list_head *list)
+dnslookup(const char *name, uint16_t port, struct cfg_value *rvalue, bool async)
 {
-	char *tmp;
-	uint16_t port;
+	struct sockaddr_in *in4;
+	struct sockaddr_in6 *in6;
+	struct dns_async tmp;
+	struct dns_async *dns;
+	int mode = async ? GAI_NOWAIT : GAI_WAIT;
+	struct addrinfo *results = NULL, *ai;
+	struct saddr *saddr = NULL;
+	bool rv = false;
 	int r;
+
+	if (port < 1 || strlen(name) >= sizeof(dns->name))
+		goto out;
+
+	if (async) {
+		rvalue->type = CFG_VAL_TYPE_ASYNC_ADDRS;
+		rvalue->dns_async = NULL;
+		dns = zmalloc(sizeof(*dns));
+		if (!dns) {
+			error("async DNS lookup of %s failed: %m\n", name);
+			goto out;
+		}
+		debug(DBG_DNS, "doing async DNS lookup of %s: %p\n", name, dns);
+	} else {
+		memset(&tmp, 0, sizeof(tmp));
+		dns = &tmp;
+		debug(DBG_DNS, "doing sync DNS lookup of %s\n", name);
+	}
+
+	sprintf(dns->name, "%s", name);	
+	sprintf(dns->port, "%" PRIu16, port);
+
+	dns->req.ai_family = AF_UNSPEC;
+	dns->req.ai_socktype = SOCK_STREAM;
+	dns->req.ai_protocol = 0;
+	dns->req.ai_flags = AI_NUMERICSERV;
+
+	dns->sev.sigev_notify = SIGEV_SIGNAL;
+	dns->sev.sigev_signo = SIGUSR1;
+	dns->sev.sigev_value.sival_ptr = dns;
+
+	dns->gcb.ar_name = dns->name;
+	dns->gcb.ar_service = dns->port;
+	dns->gcb.ar_request = &dns->req;
+
+	struct gaicb *gcbs[] = { &dns->gcb };
+
+	r = getaddrinfo_a(mode, gcbs, ARRAY_SIZE(gcbs), &dns->sev);
+	if (r != 0) {
+		error("getaddrinfo(%s:%" PRIu16 "): %s\n", name, port, gai_strerror(r));
+		goto out;
+	}
+
+	if (async) {
+		rvalue->dns_async = dns;
+		rv = true;
+		goto out;
+	}
+
+	results = dns->gcb.ar_result;
+
+	for (ai = results; ai; ai = ai->ai_next) {
+		saddr = zmalloc(sizeof(*saddr));
+		if (!saddr) {
+			error("sync DNS lookup of %s failed: %m\n", name);
+			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);
+			error("addrstr: %s\n", saddr->addrstr);
+			list_add(&saddr->list, &rvalue->saddrs);
+			break;
+
+		case AF_INET6:
+			in6 = (struct sockaddr_in6 *)ai->ai_addr;
+			saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
+			error("addrstr: %s\n", saddr->addrstr);
+			list_add(&saddr->list, &rvalue->saddrs);
+			break;
+
+		default:
+			error("getaddrinfo(%s:%s): unknown address family (%i)\n",
+			      dns->name, dns->port, ai->ai_family);
+			xfree(saddr);
+			break;
+		}
+	}
+
+	rv = true;
+
+out:
+	freeaddrinfo(results);
+	return rv;
+}
+
+static bool
+strtosockaddrs(const char *str, struct cfg_value *rvalue, bool async)
+{
 	struct saddr *saddr;
+	uint16_t port;
+	char *tmp;
+	struct list_head *list;
+	unsigned naddrs = 0;
 
-	if (!str || *str == '\0' || !list)
+	if (!str || *str == '\0' || !rvalue)
 		return false;
+
+	rvalue->type = CFG_VAL_TYPE_ADDRS;
+	list = &rvalue->saddrs;
 	list_init(list);
 
 	if (*str == '[') {
@@ -102,6 +204,7 @@ strtosockaddrs(const char *str, struct list_head *list)
 			goto error;
 
 		saddr_set_ipv6(saddr, NULL, htons(port));
+		naddrs++;
 
 	} else if (*str == '*') {
 		/* IPv4, *:p */
@@ -121,6 +224,7 @@ strtosockaddrs(const char *str, struct list_head *list)
 
 		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
 		list_add(&saddr->list, list);
+		naddrs++;
 
 	} else if ((tmp = strchr(str, ':'))) {
 		/* IPv4, a.b.c.d:p or IPv4/6 hostname:p */
@@ -136,63 +240,17 @@ strtosockaddrs(const char *str, struct list_head *list)
 			goto error;
 
 		if (inet_pton(AF_INET, str, &saddr->in4.sin_addr) > 0) {
-			debug(DBG_CFG, "got an IPv4:port (%s)\n", str);
+			debug(DBG_CFG, "got an IPv4:port (%s:%" PRIu16 ")\n", str, port);
 			saddr_set_ipv4(saddr, saddr->in4.sin_addr.s_addr, htons(port));
 			list_add(&saddr->list, list);
+			naddrs++;
 			goto success;
-		} else {
-			xfree(saddr);
-		}
+		} 
 
-		struct addrinfo hints = {
-			.ai_family = AF_UNSPEC,
-			.ai_socktype = SOCK_STREAM,
-			.ai_protocol = 0,
-			.ai_flags = 0,
-		};
-		struct addrinfo *results, *ai;
-
-		/* FIXME: This is completely synchronous but getaddrinfo_a is not very ergonomic */
-		r = getaddrinfo(str, tmp, &hints, &results);
-		if (r != 0) {
-			error("getaddrinfo(%s): %s\n", str, gai_strerror(r));
+		xfree(saddr);
+		debug(DBG_CFG, "maybe got a hostname:port (%s:%" PRIu16 ")\n", str, port);
+		if (!dnslookup(str, port, rvalue, async))
 			goto error;
-		}
-
-		debug(DBG_CFG, "got a hostname:port (%s)\n", str);
-		for (ai = results; ai; ai = ai->ai_next) {
-			saddr = zmalloc(sizeof(*saddr));
-			if (!saddr) {
-				freeaddrinfo(results);
-				goto error;
-			}
-
-			switch (ai->ai_family) {
-			case AF_INET: {
-				struct sockaddr_in *in4 = (struct sockaddr_in *)ai->ai_addr;
-
-				saddr_set_ipv4(saddr, in4->sin_addr.s_addr, htons(port));
-				list_add(&saddr->list, list);
-				break;
-			}
-
-			case AF_INET6: {
-				struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)ai->ai_addr;
-
-				saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
-				list_add(&saddr->list, list);
-				break;
-			}
-
-			default:
-				error("getaddrinfo(%s): unknown address family (%i)\n",
-				      str, ai->ai_family);
-				xfree(saddr);
-				break;
-			}
-		}
-
-		freeaddrinfo(results);
 
 	} else if (strtou16_strict(tmp, &port) == 0) {
 		/* Port */
@@ -204,6 +262,7 @@ strtosockaddrs(const char *str, struct list_head *list)
 
 		saddr_set_ipv6(saddr, &in6addr_any, htons(port));
 		list_add(&saddr->list, list);
+		naddrs++;
 
 		saddr = zmalloc(sizeof(*saddr));
 		if (!saddr)
@@ -211,6 +270,7 @@ strtosockaddrs(const char *str, struct list_head *list)
 
 		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
 		list_add(&saddr->list, list);
+		naddrs++;
 
 	} else {
 		/* Unknown */
@@ -219,22 +279,28 @@ strtosockaddrs(const char *str, struct list_head *list)
 	}
 
 success:
-	if (list_empty(list)) {
-		error("empty address list!?\n");
-		return false;
-	} else {
-		int i = 0;
+	switch (rvalue->type) {
+	case CFG_VAL_TYPE_ADDRS:
+		if (list_empty(list) || naddrs == 0) {
+			error("empty address list!?\n");
+			return false;
+		}
 
-		list_for_each_entry(saddr, list, list)
-			i++;
+		debug(DBG_CFG, "parsed to %u addresses\n", naddrs);
+		return true;
 
-		debug(DBG_CFG, "parsed to %i addresses\n", i);
-	}
+	case CFG_VAL_TYPE_ASYNC_ADDRS:
+		debug(DBG_CFG, "looking up address asynchronously\n");
+		return true;
 
-	return true;
+	default:
+		error("invalid rvalue type\n");
+		rvalue->type = CFG_VAL_TYPE_INVALID;
+		break;
+	}
 
 error:
-	if (!list_empty(list)) {
+	if (rvalue->type == CFG_VAL_TYPE_ADDRS && !list_empty(list)) {
 		struct saddr *tmp;
 
 		list_for_each_entry_safe(saddr, tmp, list, list) {
@@ -249,7 +315,7 @@ error:
 bool
 config_parse_line(struct cfg *cfg, const char *filename, char **buf,
 		  struct cfg_key_value_map *kvmap, int *rkey,
-		  const char **rkeyname, union cfg_value *rvalue)
+		  const char **rkeyname, struct cfg_value *rvalue)
 {
 	char *line, *tmp, *key;
 	int i;
@@ -301,6 +367,7 @@ config_parse_line(struct cfg *cfg, const char *filename, char **buf,
 		switch (kvmap[i].value_type) {
 
 		case CFG_VAL_TYPE_STRING:
+			rvalue->type = CFG_VAL_TYPE_STRING;
 			rvalue->str = tmp;
 			break;
 
@@ -309,26 +376,61 @@ config_parse_line(struct cfg *cfg, const char *filename, char **buf,
 
 			if (strtou16_strict(tmp, &v) < 0)
 				goto error;
+
+			rvalue->type = CFG_VAL_TYPE_UINT16;
 			rvalue->uint16 = v;
 			break;
 		}
 
-		case CFG_VAL_TYPE_ADDRS: {
-			if (!strtosockaddrs(tmp, &rvalue->saddrs))
+		case CFG_VAL_TYPE_ADDRS:
+			if (!strtosockaddrs(tmp, rvalue, false))
+				goto error;
+
+			if (rvalue->type != CFG_VAL_TYPE_ADDRS) {
+				error("invalid type returned from strtosockaddrs\n");
 				goto error;
+			}
+
 			if (list_empty(&rvalue->saddrs)) {
 				error("empty address list\n");
 				goto error;
 			}
 			break;
-		}
+
+		case CFG_VAL_TYPE_ASYNC_ADDRS:
+			if (!strtosockaddrs(tmp, rvalue, true))
+				goto error;
+
+			switch (rvalue->type) {
+			case CFG_VAL_TYPE_ADDRS:
+				if (list_empty(&rvalue->saddrs)) {
+					error("empty address list\n");
+					goto error;
+				}
+				break;
+
+			case CFG_VAL_TYPE_ASYNC_ADDRS:
+				if (!rvalue->dns_async) {
+					error("dns_async not set\n");
+					goto error;
+				}
+				break;
+
+			default:
+				error("invalid type returned from strtosockaddrs\n");
+				goto error;
+			}
+
+			break;
 
 		case CFG_VAL_TYPE_BOOL:
-			if (!strcasecmp(tmp, "yes"))
+			if (!strcasecmp(tmp, "yes") || !strcasecmp(tmp, "true")) {
+				rvalue->type = CFG_VAL_TYPE_BOOL;
 				rvalue->boolean = true;
-			else if (!strcasecmp(tmp, "no"))
+			} else if (!strcasecmp(tmp, "no") || !strcasecmp(tmp, "false")) {
+				rvalue->type = CFG_VAL_TYPE_BOOL;
 				rvalue->boolean = false;
-			else {
+			} else {
 				error("invalid boolean value (%s)\n", tmp);
 				goto error;
 			}
@@ -340,6 +442,14 @@ config_parse_line(struct cfg *cfg, const char *filename, char **buf,
 			goto error;
 		}
 
+		/* sanity check */
+		if ((rvalue->type != kvmap[i].value_type) &&
+		    ((kvmap[i].value_type != CFG_VAL_TYPE_ASYNC_ADDRS) &&
+		     (rvalue->type != CFG_VAL_TYPE_ADDRS))) {
+			error("rvalue->type != kvmap->type\n");
+			goto error;
+		}
+
 		*rkey = kvmap[i].key_value;
 		*rkeyname = kvmap[i].key_name;
 		return true;
@@ -348,6 +458,7 @@ config_parse_line(struct cfg *cfg, const char *filename, char **buf,
 error:
 	/* FIXME: the line is already mangled here, a line number would be nice */
 	error("%s: invalid config line: %s\n", filename, line);
+	rvalue->type = CFG_VAL_TYPE_INVALID;
 	*rkey = 0;
 	*rkeyname = NULL;
 	return true;