Merge pull request #4639 from opensourcerouting/c-ares-lib

make c-ares DNS resolver available as lib

configure.ac

@@ -1560,7 +1560,7 @@ if test "${NHRPD}" != ""; then
     AC_MSG_ERROR([trying to build nhrpd, but libcares not found. install c-ares and its -dev headers.])
   ])
 fi
-
+AM_CONDITIONAL([CARES], [test "${NHRPD}" != ""])
 
 dnl ------------------
 dnl check Net-SNMP library

debian/frr.install

@@ -2,6 +2,7 @@ etc/
 usr/bin/vtysh
 usr/bin/mtracebis
 usr/lib/*/frr/libfrr.*
+usr/lib/*/frr/libfrrcares.*
 usr/lib/*/frr/libfrrospfapiclient.*
 usr/lib/frr/*.sh
 usr/lib/frr/*d

lib/command.c

@@ -85,6 +85,7 @@ const char *node_names[] = {
 	"northbound debug",	    // NORTHBOUND_DEBUG_NODE,
 	"vnc debug",		    // DEBUG_VNC_NODE,
 	"route-map debug",	    /* RMAP_DEBUG_NODE */
+	"resolver debug",	    /* RESOLVER_DEBUG_NODE */
 	"aaa",			    // AAA_NODE,
 	"keychain",		    // KEYCHAIN_NODE,
 	"keychain key",		    // KEYCHAIN_KEY_NODE,

lib/command.h

@@ -94,6 +94,7 @@ enum node_type {
 	NORTHBOUND_DEBUG_NODE,	 /* Northbound Debug node. */
 	DEBUG_VNC_NODE,		 /* Debug VNC node. */
 	RMAP_DEBUG_NODE,         /* Route-map debug node */
+	RESOLVER_DEBUG_NODE,	 /* Resolver debug node */
 	AAA_NODE,		 /* AAA node. */
 	KEYCHAIN_NODE,		 /* Key-chain node. */
 	KEYCHAIN_KEY_NODE,       /* Key-chain key node. */

lib/lib_errors.c

@@ -356,6 +356,12 @@ static struct log_ref ferr_lib_err[] = {
 		.description = "A callback used to process a configuration change has returned an error while applying the changes",
 		.suggestion = "Gather log data and open an Issue.",
 	},
+	{
+		.code = EC_LIB_RESOLVER,
+		.title = "DNS Resolution",
+		.description = "An error was detected while attempting to resolve a hostname",
+		.suggestion = "Ensure that DNS is working properly and the hostname is configured in dns.  If you are still seeing this error, open an issue"
+	},
 	{
 		.code = END_FERR,
 	}

lib/lib_errors.h

@@ -84,6 +84,7 @@ enum lib_log_refs {
 	EC_LIB_GRPC_INIT,
 	EC_LIB_ID_CONSISTENCY,
 	EC_LIB_ID_EXHAUST,
+	EC_LIB_RESOLVER,
 };
 
 extern void lib_error_init(void);

lib/resolver.c

@@ -17,17 +17,18 @@
 #include "vector.h"
 #include "thread.h"
 #include "lib_errors.h"
-
-#include "nhrpd.h"
-#include "nhrp_errors.h"
+#include "resolver.h"
+#include "command.h"
 
 struct resolver_state {
 	ares_channel channel;
+	struct thread_master *master;
 	struct thread *timeout;
 	vector read_threads, write_threads;
 };
 
 static struct resolver_state state;
+static bool resolver_debug;
 
 #define THREAD_RUNNING ((struct thread *)-1)
 
@@ -54,7 +55,8 @@ static int resolver_cb_socket_readable(struct thread *t)
 	ares_process_fd(r->channel, fd, ARES_SOCKET_BAD);
 	if (vector_lookup(r->read_threads, fd) == THREAD_RUNNING) {
 		t = NULL;
-		thread_add_read(master, resolver_cb_socket_readable, r, fd, &t);
+		thread_add_read(r->master, resolver_cb_socket_readable, r, fd,
+				&t);
 		vector_set_index(r->read_threads, fd, t);
 	}
 	resolver_update_timeouts(r);
@@ -71,7 +73,7 @@ static int resolver_cb_socket_writable(struct thread *t)
 	ares_process_fd(r->channel, ARES_SOCKET_BAD, fd);
 	if (vector_lookup(r->write_threads, fd) == THREAD_RUNNING) {
 		t = NULL;
-		thread_add_write(master, resolver_cb_socket_writable, r, fd,
+		thread_add_write(r->master, resolver_cb_socket_writable, r, fd,
 				 &t);
 		vector_set_index(r->write_threads, fd, t);
 	}
@@ -91,8 +93,8 @@ static void resolver_update_timeouts(struct resolver_state *r)
 	tv = ares_timeout(r->channel, NULL, &tvbuf);
 	if (tv) {
 		unsigned int timeoutms = tv->tv_sec * 1000 + tv->tv_usec / 1000;
-		thread_add_timer_msec(master, resolver_cb_timeout, r, timeoutms,
-				      &r->timeout);
+		thread_add_timer_msec(r->master, resolver_cb_timeout, r,
+				      timeoutms, &r->timeout);
 	}
 }
 
@@ -105,8 +107,8 @@ static void ares_socket_cb(void *data, ares_socket_t fd, int readable,
 	if (readable) {
 		t = vector_lookup_ensure(r->read_threads, fd);
 		if (!t) {
-			thread_add_read(master, resolver_cb_socket_readable, r,
-					fd, &t);
+			thread_add_read(r->master, resolver_cb_socket_readable,
+					r, fd, &t);
 			vector_set_index(r->read_threads, fd, t);
 		}
 	} else {
@@ -122,8 +124,8 @@ static void ares_socket_cb(void *data, ares_socket_t fd, int readable,
 	if (writable) {
 		t = vector_lookup_ensure(r->write_threads, fd);
 		if (!t) {
-			thread_add_read(master, resolver_cb_socket_writable, r,
-					fd, &t);
+			thread_add_read(r->master, resolver_cb_socket_writable,
+					r, fd, &t);
 			vector_set_index(r->write_threads, fd, t);
 		}
 	} else {
@@ -137,37 +139,23 @@ static void ares_socket_cb(void *data, ares_socket_t fd, int readable,
 	}
 }
 
-void resolver_init(void)
-{
-	struct ares_options ares_opts;
-
-	state.read_threads = vector_init(1);
-	state.write_threads = vector_init(1);
-
-	ares_opts = (struct ares_options){
-		.sock_state_cb = &ares_socket_cb,
-		.sock_state_cb_data = &state,
-		.timeout = 2,
-		.tries = 3,
-	};
-
-	ares_init_options(&state.channel, &ares_opts,
-			  ARES_OPT_SOCK_STATE_CB | ARES_OPT_TIMEOUT
-				  | ARES_OPT_TRIES);
-}
-
 
 static void ares_address_cb(void *arg, int status, int timeouts,
 			    struct hostent *he)
 {
 	struct resolver_query *query = (struct resolver_query *)arg;
 	union sockunion addr[16];
+	void (*callback)(struct resolver_query *, int, union sockunion *);
 	size_t i;
 
+	callback = query->callback;
+	query->callback = NULL;
+
 	if (status != ARES_SUCCESS) {
-		debugf(NHRP_DEBUG_COMMON, "[%p] Resolving failed", query);
-		query->callback(query, -1, NULL);
-		query->callback = NULL;
+		if (resolver_debug)
+			zlog_debug("[%p] Resolving failed", query);
+
+		callback(query, -1, NULL);
 		return;
 	}
 
@@ -186,10 +174,10 @@ static void ares_address_cb(void *arg, int status, int timeouts,
 		}
 	}
 
-	debugf(NHRP_DEBUG_COMMON, "[%p] Resolved with %d results", query,
-	       (int)i);
-	query->callback(query, i, &addr[0]);
-	query->callback = NULL;
+	if (resolver_debug)
+		zlog_debug("[%p] Resolved with %d results", query, (int)i);
+
+	callback(query, i, &addr[0]);
 }
 
 void resolver_resolve(struct resolver_query *query, int af,
@@ -199,15 +187,61 @@ void resolver_resolve(struct resolver_query *query, int af,
 {
 	if (query->callback != NULL) {
 		flog_err(
-			EC_NHRP_RESOLVER,
+			EC_LIB_RESOLVER,
 			"Trying to resolve '%s', but previous query was not finished yet",
 			hostname);
 		return;
 	}
 
-	debugf(NHRP_DEBUG_COMMON, "[%p] Resolving '%s'", query, hostname);
+	if (resolver_debug)
+		zlog_debug("[%p] Resolving '%s'", query, hostname);
 
 	query->callback = callback;
 	ares_gethostbyname(state.channel, hostname, af, ares_address_cb, query);
 	resolver_update_timeouts(&state);
 }
+
+DEFUN(debug_resolver,
+      debug_resolver_cmd,
+      "[no] debug resolver",
+      NO_STR
+      DEBUG_STR
+      "Debug DNS resolver actions\n")
+{
+	resolver_debug = (argc == 2);
+	return CMD_SUCCESS;
+}
+
+static struct cmd_node resolver_debug_node = {RESOLVER_DEBUG_NODE, "", 1};
+
+static int resolver_config_write_debug(struct vty *vty)
+{
+	if (resolver_debug)
+		vty_out(vty, "debug resolver\n");
+	return 1;
+}
+
+
+void resolver_init(struct thread_master *tm)
+{
+	struct ares_options ares_opts;
+
+	state.master = tm;
+	state.read_threads = vector_init(1);
+	state.write_threads = vector_init(1);
+
+	ares_opts = (struct ares_options){
+		.sock_state_cb = &ares_socket_cb,
+		.sock_state_cb_data = &state,
+		.timeout = 2,
+		.tries = 3,
+	};
+
+	ares_init_options(&state.channel, &ares_opts,
+			  ARES_OPT_SOCK_STATE_CB | ARES_OPT_TIMEOUT
+				  | ARES_OPT_TRIES);
+
+	install_node(&resolver_debug_node, resolver_config_write_debug);
+	install_element(CONFIG_NODE, &debug_resolver_cmd);
+	install_element(ENABLE_NODE, &debug_resolver_cmd);
+}

lib/resolver.h

@@ -0,0 +1,25 @@
+/* C-Ares integration to Quagga mainloop
+ * Copyright (c) 2014-2015 Timo Teräs
+ *
+ * This file is free software: you may copy, redistribute 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.
+ */
+
+#ifndef _FRR_RESOLVER_H
+#define _FRR_RESOLVER_H
+
+#include "thread.h"
+#include "sockunion.h"
+
+struct resolver_query {
+	void (*callback)(struct resolver_query *, int n, union sockunion *);
+};
+
+void resolver_init(struct thread_master *tm);
+void resolver_resolve(struct resolver_query *query, int af,
+		      const char *hostname, void (*cb)(struct resolver_query *,
+						       int, union sockunion *));
+
+#endif /* _FRR_RESOLVER_H */

lib/subdir.am

@@ -285,6 +285,21 @@ lib_libfrrsnmp_la_SOURCES = \
 	lib/snmp.c \
 	# end
 
+#
+# c-ares support
+#
+if CARES
+lib_LTLIBRARIES += lib/libfrrcares.la
+pkginclude_HEADERS += lib/resolver.h
+endif
+
+lib_libfrrcares_la_CFLAGS = $(WERROR) $(CARES_CFLAGS)
+lib_libfrrcares_la_LDFLAGS = -version-info 0:0:0
+lib_libfrrcares_la_LIBADD = $(CARES_LIBS)
+lib_libfrrcares_la_SOURCES = \
+	lib/resolver.c \
+	#end
+
 #
 # ZeroMQ support
 #

nhrpd/nhrp_errors.c

@@ -31,12 +31,6 @@ static struct log_ref ferr_nhrp_err[] = {
 		.description = "NHRP has detected a error with the Strongswan code",
 		.suggestion = "Ensure that StrongSwan is configured correctly.  Restart StrongSwan and FRR"
 	},
-	{
-		.code = EC_NHRP_RESOLVER,
-		.title = "NHRP DNS Resolution",
-		.description = "NHRP has detected an error in an attempt to resolve a hostname",
-		.suggestion = "Ensure that DNS is working properly and the hostname is configured in dns.  If you are still seeing this error, open an issue"
-	},
 	{
 		.code = END_FERR,
 	}

nhrpd/nhrp_errors.h

@@ -25,7 +25,6 @@
 
 enum nhrp_log_refs {
 	EC_NHRP_SWAN = NHRP_FERR_START,
-	EC_NHRP_RESOLVER,
 };
 
 extern void nhrp_error_init(void);

nhrpd/nhrp_main.c

@@ -141,7 +141,7 @@ int main(int argc, char **argv)
 	nhrp_error_init();
 	vrf_init(NULL, NULL, NULL, NULL, NULL);
 	nhrp_interface_init();
-	resolver_init();
+	resolver_init(master);
 
 	/* Run with elevated capabilities, as for all netlink activity
 	 * we need privileges anyway. */

nhrpd/nhrpd.h

@@ -16,6 +16,7 @@
 #include "zclient.h"
 #include "debug.h"
 #include "memory.h"
+#include "resolver.h"
 
 DECLARE_MGROUP(NHRPD)
 
@@ -84,15 +85,6 @@ static inline int notifier_active(struct notifier_list *l)
 	return !list_empty(&l->notifier_head);
 }
 
-struct resolver_query {
-	void (*callback)(struct resolver_query *, int n, union sockunion *);
-};
-
-void resolver_init(void);
-void resolver_resolve(struct resolver_query *query, int af,
-		      const char *hostname, void (*cb)(struct resolver_query *,
-						       int, union sockunion *));
-
 void nhrp_zebra_init(void);
 void nhrp_zebra_terminate(void);
 

nhrpd/subdir.am

@@ -8,8 +8,7 @@ vtysh_scan += $(top_srcdir)/nhrpd/nhrp_vty.c
 man8 += $(MANBUILD)/nhrpd.8
 endif
 
-nhrpd_nhrpd_LDADD = lib/libfrr.la $(LIBCAP) $(CARES_LIBS)
-nhrpd_nhrpd_CFLAGS = $(AM_CFLAGS) $(CARES_CFLAGS)
+nhrpd_nhrpd_LDADD = lib/libfrr.la lib/libfrrcares.la $(LIBCAP)
 nhrpd_nhrpd_SOURCES = \
 	nhrpd/linux.c \
 	nhrpd/netlink_arp.c \
@@ -27,7 +26,6 @@ nhrpd_nhrpd_SOURCES = \
 	nhrpd/nhrp_vc.c \
 	nhrpd/nhrp_vty.c \
 	nhrpd/reqid.c \
-	nhrpd/resolver.c \
 	nhrpd/vici.c \
 	nhrpd/zbuf.c \
 	nhrpd/znl.c \

vtysh/vtysh_config.c

@@ -377,6 +377,9 @@ void vtysh_config_parse_line(void *arg, const char *line)
 				 strlen("debug route-map"))
 			 == 0)
 			config = config_get(RMAP_DEBUG_NODE, line);
+		else if (strncmp(line, "debug resolver",
+				 strlen("debug resolver")) == 0)
+			config = config_get(RESOLVER_DEBUG_NODE, line);
 		else if (strncmp(line, "debug", strlen("debug")) == 0)
 			config = config_get(DEBUG_NODE, line);
 		else if (strncmp(line, "password", strlen("password")) == 0
@@ -423,7 +426,7 @@ void vtysh_config_parse_line(void *arg, const char *line)
 	 || (I) == PREFIX_IPV6_NODE || (I) == FORWARDING_NODE                  \
 	 || (I) == DEBUG_NODE || (I) == AAA_NODE || (I) == VRF_DEBUG_NODE      \
 	 || (I) == NORTHBOUND_DEBUG_NODE || (I) == RMAP_DEBUG_NODE             \
-	 || (I) == MPLS_NODE)
+	 || (I) == RESOLVER_DEBUG_NODE || (I) == MPLS_NODE)
 
 /* Display configuration to file pointer. */
 void vtysh_config_dump(void)