From 91a7ca50f3f8a2c7bb01113fa3849cb5e153a70f Mon Sep 17 00:00:00 2001
From: David Härdeman <david@hardeman.nu>
Date: Fri, 19 Jun 2020 19:11:48 +0200
Subject: Add support for async DNS

---
 main.c | 86 ++++++++++++++++++++++++++++++++++++++++--------------------------
 1 file changed, 52 insertions(+), 34 deletions(-)

(limited to 'main.c')

diff --git a/main.c b/main.c
index e748ff6..b2accc1 100644
--- a/main.c
+++ b/main.c
@@ -255,7 +255,7 @@ cfg_read(struct cfg *cfg)
 	while (true) {
 		int key;
 		const char *keyname;
-		union cfg_value value;
+		struct cfg_value value;
 
 		if (!config_parse_line(cfg, path, &pos, mcfg_key_map,
 				       &key, &keyname, &value))
@@ -276,6 +276,7 @@ cfg_read(struct cfg *cfg)
 			cfg->igmp_iface = xstrdup(value.str);
 			if (!cfg->igmp_iface)
 				perrordie("xstrdup");
+
 			break;
 
 		case MCFG_KEY_INVALID:
@@ -291,40 +292,46 @@ const struct {
 } debug_category_str[] = {
 	{
 		.name = "config",
-		.val = DBG_CFG
+		.val = DBG_CFG,
 	},{
 		.name = "refcount",
-		.val = DBG_REF
+		.val = DBG_REF,
 	},{
 		.name = "malloc",
-		.val = DBG_MALLOC
+		.val = DBG_MALLOC,
 	},{
 		.name = "announce",
-		.val = DBG_ANN
+		.val = DBG_ANN,
 	},{
-		.name = "signals",
-		.val = DBG_SIG
+		.name = "signal",
+		.val = DBG_SIG,
 	},{
 		.name = "uring",
-		.val = DBG_UR
+		.val = DBG_UR,
 	},{
 		.name = "server",
-		.val = DBG_SRV
+		.val = DBG_SRV,
 	},{
 		.name = "proxy",
-		.val = DBG_PROXY
+		.val = DBG_PROXY,
 	},{
 		.name = "rcon",
-		.val = DBG_RCON
+		.val = DBG_RCON,
 	},{
 		.name = "idle",
-		.val = DBG_IDLE
+		.val = DBG_IDLE,
 	},{
 		.name = "igmp",
-		.val = DBG_IGMP
+		.val = DBG_IGMP,
+	},{
+		.name = "systemd",
+		.val = DBG_SYSD,
+	},{
+		.name = "dns",
+		.val = DBG_DNS,
 	},{
 		.name = NULL,
-		.val = 0
+		.val = 0,
 	}
 };
 
@@ -561,24 +568,19 @@ dump_tree(struct cfg *cfg)
 	debug(DBG_REF, "\n\n\n\n");
 }
 
+static struct dns_async *hack_dns = NULL;
+
 static void
 signalfd_read(struct cfg *cfg, struct uring_task *task, int res)
 {
 	struct signalfd_ev *sev = container_of(task, struct signalfd_ev, task);
 	struct server *server, *stmp;
-	static int count = 0;
 
 	if (task->dead) {
 		debug(DBG_SIG, "task dead\n");
 		return;
 	}
 
-	count++;
-	if (count > 5) {
-		error("Max signal count exceeded, force quitting\n");
-		exit(EXIT_FAILURE);
-	}
-
 	if (res != sizeof(sev->buf))
 		die("error in signalfd (%i)", res);
 
@@ -586,7 +588,7 @@ signalfd_read(struct cfg *cfg, struct uring_task *task, int res)
 		verbose("got a signal to quit\n");
 		sd_notifyf(0, "STOPPING=1\nSTATUS=Received signal, exiting");
 		exit(EXIT_SUCCESS);
-	} else {
+	} else if (sev->buf < 10000) {
 		verbose("got a signal to dump tree\n");
 		sd_notifyf(0, "STOPPING=1\nSTATUS=Received signal, exiting");
 		dump_tree(cfg);
@@ -598,25 +600,45 @@ signalfd_read(struct cfg *cfg, struct uring_task *task, int res)
 			server_delete(cfg, server);
 		uring_delete(cfg);
 		return;
+	} else {
+		debug(DBG_DNS, "DNS lookup complete, dns: %p, dns->cb: %p\n",
+		      hack_dns,
+		      hack_dns ? hack_dns->callback : NULL);
+
+		if (!hack_dns || !hack_dns->callback) {
+			error("DNS callback not set\n");
+			goto out;
+		}
+
+		if (hack_dns && hack_dns->callback)
+			hack_dns->callback(hack_dns);
 	}
 
+out:
 	uring_read(cfg, &sev->task, &sev->buf, sizeof(sev->buf), signalfd_read);
 }
 
 static int hack_efd = -1;
 
 static void
-hack_handler(int signum)
+hack_handler(int signum, siginfo_t *info, void *ucontext)
 {
 	uint64_t val;
-	static int count = 0;
 
 	switch (signum) {
+	case SIGUSR1:
+		debug(DBG_SIG, "Got a SIGUSR1\n");
+		if (info->si_code != SI_ASYNCNL || info->si_signo != SIGUSR1 || !info->si_ptr) {
+			debug(DBG_SIG, "unexpected values in siginfo\n");
+			return;
+		}
+		debug(DBG_SIG, "SIGUSR1 struct dns_async: %p\n", info->si_ptr);
+		hack_dns = info->si_ptr;
+		val = 10000;
+		break;
 	case SIGINT:
 		debug(DBG_SIG, "Got a SIGINT\n");
 		val = 1000;
-		if (count > 3)
-			dump_tree(cfghack);
 		break;
 	case SIGHUP:
 		debug(DBG_SIG, "Got a SIGHUP\n");
@@ -632,13 +654,7 @@ hack_handler(int signum)
 		break;
 	}
 
-	if (count > 5) {
-		error("Max signal count exceeded, force quitting\n");
-		exit(EXIT_FAILURE);
-	}
-
 	write(hack_efd, &val, sizeof(val));
-	count++;
 }
 
 static void
@@ -664,14 +680,16 @@ signalfd_init(struct cfg *cfg)
 
 	struct sigaction action;
 	sigfillset(&action.sa_mask);
-	action.sa_handler = hack_handler;
-	action.sa_flags = 0;
+	action.sa_sigaction = hack_handler;
+	action.sa_flags = SA_SIGINFO;
 
 	sigaction(SIGINT, &action, NULL);
 	sigaction(SIGHUP, &action, NULL);
 	sigaction(SIGTERM, &action, NULL);
+	sigaction(SIGUSR1, &action, NULL);
 
 	action.sa_handler = SIG_IGN;
+	action.sa_flags = 0;
 	sigaction(SIGPIPE, &action, NULL);
 
 	sfd = eventfd(0, EFD_CLOEXEC);
-- 
cgit v1.2.3