all: add log helpers

avoids multiple syslog.h include

(sync with implementation in odhcpd)

We deprecate the `-v` param. Add new `-l` param for level,
identical to odhcpd.

The odhcp6c `dhcpv6.sh` script in openwrt main should be updated
to recognize this change, but it is harmless if it is not changed.

Signed-off-by: Paul Donald <newtwen+github@gmail.com>
Link: https://github.com/openwrt/odhcp6c/pull/142
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

8 files changed, 108 insertions, 71 deletions

diff --git a/src/config.c b/src/config.c
index 7db8b02..2866175 100644
--- a/src/config.c
+++ b/src/config.c
@@ -64,7 +64,6 @@
 #include <resolv.h>
 #include <stdlib.h>
 #include <string.h>
-#include <syslog.h>
 
 #include "config.h"
 #include "odhcp6c.h"
@@ -78,6 +77,7 @@ struct config_dhcp *config_dhcp_get(void) {
 }
 
 void config_dhcp_reset(void) {
+	config_dhcp.log_level = LOG_WARNING;
 	config_dhcp.release = true;
 	config_dhcp.dscp = 0;
 	config_dhcp.sk_prio = 0;
@@ -119,7 +119,7 @@ void config_set_release(bool enable) {
 
 bool config_set_dscp(unsigned int value) {
 	if (value > 63) {
-		syslog(LOG_ERR, "Invalid DSCP value");
+		error("Invalid DSCP value");
 		return false;
 	}
 	config_dhcp.dscp = value;
@@ -128,7 +128,7 @@ bool config_set_dscp(unsigned int value) {
 
 bool config_set_sk_priority(unsigned int priority) {
 	if (priority > 6) {
-		syslog(LOG_ERR, "Invalid SK priority value");
+		error("Invalid SK priority value");
 		return false;
 	}
 	config_dhcp.sk_prio = priority;
@@ -152,7 +152,7 @@ bool config_set_request_addresses(char* mode) {
 	} else if (!strcmp(mode, "try")) {
 		config_dhcp.ia_na_mode = IA_MODE_TRY;
 	} else {
-		syslog(LOG_ERR, "Invalid IA_NA Request Addresses mode");
+		error("Invalid IA_NA Request Addresses mode");
 		return false;
 	}
 
@@ -172,7 +172,7 @@ bool config_set_request_prefix(unsigned int length, unsigned int id) {
 		prefix.iaid = htonl(id);
 
 		if (odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix))) {
-			syslog(LOG_ERR, "Failed to set request IPv6-Prefix");
+			error("Failed to set request IPv6-Prefix");
 			return false;
 		}
 	}
@@ -203,13 +203,13 @@ void config_clear_requested_options(void) {
 
 bool config_add_requested_options(unsigned int option) {
 	if (option > UINT16_MAX) {
-		syslog(LOG_ERR, "Invalid requested option");
+		error("Invalid requested option");
 		return false;
 	}
 
 	option = htons(option);
 	if (odhcp6c_insert_state(STATE_ORO, 0, &option, 2)) {
-		syslog(LOG_ERR, "Failed to set requested option");
+		error("Failed to set requested option");
 		return false;
 	}
 	config_dhcp.oro_user_cnt++;
@@ -227,7 +227,7 @@ bool config_add_send_options(char* option) {
 bool config_set_rtx_delay_max(enum config_dhcp_msg msg, unsigned int value)
 {
 	if (msg >= CONFIG_DHCP_MAX || value > UINT8_MAX) {
-		syslog(LOG_ERR, "Invalid retransmission Maximum Delay value");
+		error("Invalid retransmission Maximum Delay value");
 		return false;
 	}
 	config_dhcp.message_rtx[msg].delay_max = value;
@@ -237,7 +237,7 @@ bool config_set_rtx_delay_max(enum config_dhcp_msg msg, unsigned int value)
 bool config_set_rtx_timeout_init(enum config_dhcp_msg msg, unsigned int value)
 {
 	if (msg >= CONFIG_DHCP_MAX || value > UINT8_MAX || value == 0) {
-		syslog(LOG_ERR, "Invalid retransmission Initial Timeout value");
+		error("Invalid retransmission Initial Timeout value");
 		return false;
 	}
 	config_dhcp.message_rtx[msg].timeout_init = value;
@@ -247,7 +247,7 @@ bool config_set_rtx_timeout_init(enum config_dhcp_msg msg, unsigned int value)
 bool config_set_rtx_timeout_max(enum config_dhcp_msg msg, unsigned int value)
 {
 	if (msg >= CONFIG_DHCP_MAX || value > UINT16_MAX) {
-		syslog(LOG_ERR, "Invalid retransmission Maximum Timeout value");
+		error("Invalid retransmission Maximum Timeout value");
 		return false;
 	}
 	config_dhcp.message_rtx[msg].timeout_max = value;
@@ -257,7 +257,7 @@ bool config_set_rtx_timeout_max(enum config_dhcp_msg msg, unsigned int value)
 bool config_set_rtx_rc_max(enum config_dhcp_msg msg, unsigned int value)
 {
 	if (msg >= CONFIG_DHCP_MAX || value > UINT8_MAX) {
-		syslog(LOG_ERR, "Invalid retransmission Retry Attempt value");
+		error("Invalid retransmission Retry Attempt value");
 		return false;
 	}
 	config_dhcp.message_rtx[msg].rc_max = value;
@@ -267,7 +267,7 @@ bool config_set_rtx_rc_max(enum config_dhcp_msg msg, unsigned int value)
 bool config_set_irt_default(unsigned int value)
 {
 	if (value == 0) {
-		syslog(LOG_ERR, "Invalid Default Information Refresh Time value");
+		error("Invalid Default Information Refresh Time value");
 		return false;
 	}
 	config_dhcp.irt_default = value;
@@ -277,7 +277,7 @@ bool config_set_irt_default(unsigned int value)
 bool config_set_irt_min(unsigned int value)
 {
 	if (value == 0) {
-		syslog(LOG_ERR, "Invalid Minimum Information Refresh Time value");
+		error("Invalid Minimum Information Refresh Time value");
 		return false;
 	}
 	config_dhcp.irt_min = value;
@@ -287,7 +287,7 @@ bool config_set_irt_min(unsigned int value)
 bool config_set_rand_factor(unsigned int value)
 {
 	if (value > 999 || value < 10) {
-		syslog(LOG_ERR, "Invalid Random Factor value");
+		error("Invalid Random Factor value");
 		return false;
 	}
 	config_dhcp.rand_factor = value;
@@ -303,7 +303,7 @@ bool config_set_auth_protocol(const char* protocol)
 	} else if (!strcmp(protocol, "ReconfigureKeyAuthentication")) {
 		config_dhcp.auth_protocol = AUTH_PROT_RKAP;
 	} else {
-		syslog(LOG_ERR, "Invalid Authentication protocol");
+		error("Invalid Authentication protocol");
 		return false;
 	}
 
@@ -493,7 +493,7 @@ int config_add_opt(const uint16_t code, const uint8_t *data, const uint16_t len)
 
 	if (odhcp6c_add_state(STATE_OPTS, &opt_hdr, sizeof(opt_hdr)) ||
 			odhcp6c_add_state(STATE_OPTS, data, len)) {
-		syslog(LOG_ERR, "Failed to add option %hu", code);
+		error("Failed to add option %hu", code);
 		return 1;
 	}
 
diff --git a/src/config.h b/src/config.h
index 03dbf88..cce1c04 100644
--- a/src/config.h
+++ b/src/config.h
@@ -83,7 +83,9 @@ enum config_dhcp_msg {
 };
 
 struct config_dhcp {
+	bool log_syslog;
 	bool release;
+	int log_level;
 	int dscp;
 	int sk_prio;
 	bool stateful_only_mode;
diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index b8e5292..7e9415b 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -28,7 +28,6 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
-#include <syslog.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/time.h>
@@ -485,7 +484,7 @@ static int fd_set_nonblocking(int sockfd)
 {
 	int flags = fcntl(sockfd, F_GETFL, 0);
 	if (flags == -1) {
-		syslog(LOG_ERR,
+		error(
 			"Failed to get the dhcpv6 socket flags: fcntl F_GETFL failed (%s)",
 			strerror(errno));
 		return -1;
@@ -493,7 +492,7 @@ static int fd_set_nonblocking(int sockfd)
 
 	// Set the socket to non-blocking
 	if (fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) == -1) {
-		syslog(LOG_ERR,
+		error(
 			"Failed to set the dhcpv6 socket to non-blocking: fcntl F_SETFL failed (%s)",
 			strerror(errno));
 		return -1;
@@ -1019,7 +1018,7 @@ static void dhcpv6_send(enum dhcpv6_msg req_msg_type, uint8_t trid[3], uint32_t
 	if (sendmsg(sock, &msg, 0) < 0) {
 		char in6_str[INET6_ADDRSTRLEN];
 
-		syslog(LOG_ERR, "Failed to send %s message to %s (%s)",
+		error("Failed to send %s message to %s (%s)",
 			dhcpv6_msg_to_str(req_msg_type),
 			inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
 				in6_str, sizeof(in6_str)), strerror(errno));
@@ -1196,7 +1195,7 @@ static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
 				_o_fallthrough;
 			case DHCPV6_MSG_INFO_REQ:
 				msg = odata[0];
-				syslog(LOG_NOTICE, "Need to respond with %s in reply to %s",
+				notice("Need to respond with %s in reply to %s",
 				       dhcpv6_msg_to_str(msg), dhcpv6_msg_to_str(DHCPV6_MSG_RECONF));
 				break;
 
@@ -1724,7 +1723,7 @@ static unsigned int dhcpv6_parse_ia(void *opt, void *end, int *ret)
 	if (t1 > t2 && t1 > 0 && t2 > 0)
 		return 0;
 
-	syslog(LOG_INFO, "%s %04x T1 %d T2 %d", ntohs(ia_hdr->type) == DHCPV6_OPT_IA_PD ? "IA_PD" : "IA_NA", ntohl(ia_hdr->iaid), t1, t2);
+	info("%s %04x T1 %d T2 %d", ntohs(ia_hdr->type) == DHCPV6_OPT_IA_PD ? "IA_PD" : "IA_NA", ntohl(ia_hdr->iaid), t1, t2);
 
 	// Update address IA
 	dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
@@ -1825,7 +1824,7 @@ static unsigned int dhcpv6_parse_ia(void *opt, void *end, int *ret)
 				if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0))
 					updated_IAs++;
 
-				syslog(LOG_INFO, "%s/%d preferred %d valid %d",
+				info("%s/%d preferred %d valid %d",
 						inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
 						entry.length, entry.preferred , entry.valid);
 			}
@@ -1880,7 +1879,7 @@ static unsigned int dhcpv6_parse_ia(void *opt, void *end, int *ret)
 				if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0))
 					updated_IAs++;
 
-				syslog(LOG_INFO, "%s preferred %d valid %d",
+				info("%s preferred %d valid %d",
 						inet_ntop(AF_INET6, &entry.target, buf, sizeof(buf)),
 						entry.preferred , entry.valid);
 			}
@@ -1947,7 +1946,7 @@ static unsigned int dhcpv6_calc_refresh_timers(void)
 		t2 = l_t2;
 		t3 = l_t3;
 
-		syslog(LOG_INFO, "T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
+		info("T1 %"PRId64"s, T2 %"PRId64"s, T3 %"PRId64"s", t1, t2, t3);
 	}
 
 	return (unsigned int)(ia_pd_entry_cnt + ia_na_entry_cnt);
@@ -1972,7 +1971,7 @@ static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
 
 	*dst = 0;
 
-	syslog(LOG_WARNING, "Server returned %s status '%s %s'",
+	warn("Server returned %s status '%s %s'",
 		scope, dhcpv6_status_code_to_str(code), buf);
 }
 
@@ -2198,7 +2197,7 @@ int dhcpv6_send_request(enum dhcpv6_msg req_msg_type)
 		if (retx->timeout == 0)
 			return -1;
 
-		syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
+		notice("Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
 			retx->name, retx->timeout, retx->max_rc);
 
 		// Generate transaction ID
@@ -2248,7 +2247,7 @@ int dhcpv6_send_request(enum dhcpv6_msg req_msg_type)
 	case DHCPV6_MSG_UNKNOWN:
 		break;
 	default:
-		syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
+		notice("Send %s message (elapsed %"PRIu64"ms, rc %d)",
 				retx->name, elapsed, retx->rc);
 		_o_fallthrough;
 	case DHCPV6_MSG_SOLICIT:
@@ -2285,7 +2284,7 @@ int dhcpv6_receive_response(enum dhcpv6_msg req_msg_type)
 	// Receive cycle
 	len = recvmsg(sock, &msg, 0);
 	if (len < 0) {
-		syslog(LOG_ERR, "Error occurred when reading the response of (%s) error(%s)",
+		error("Error occurred when reading the response of (%s) error(%s)",
 			retx->name, strerror(errno));
 		return -1;
 	}
@@ -2317,7 +2316,7 @@ int dhcpv6_receive_response(enum dhcpv6_msg req_msg_type)
 	retx->round_start = odhcp6c_get_milli_time();
 	uint64_t elapsed = retx->round_start - retx->start;
 
-	syslog(LOG_NOTICE, "Got a valid %s after %"PRIu64"ms",
+	notice("Got a valid %s after %"PRIu64"ms",
 		dhcpv6_msg_to_str(hdr->msg_type), elapsed);
 
 	if (retx->handler_reply) {
diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 9b37c24..72705ff 100644
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -27,10 +27,10 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdlib.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 #include <strings.h>
-#include <syslog.h>
 #include <sys/syscall.h>
 #include <time.h>
 #include <unistd.h>
@@ -67,6 +67,25 @@ static time_t last_update = 0;
 static char *ifname = NULL;
 struct config_dhcp *config_dhcp = NULL;
 
+void __iflog(int lvl, const char *fmt, ...)
+{
+	va_list ap;
+
+	if (lvl > config_dhcp->log_level)
+		return;
+
+	va_start(ap, fmt);
+
+	if (config_dhcp->log_syslog) {
+		vsyslog(lvl, fmt, ap);
+	} else {
+		vfprintf(stderr, fmt, ap);
+		fprintf(stderr, "\n");
+	}
+
+	va_end(ap);
+}
+
 static unsigned int script_sync_delay = 10;
 static unsigned int script_accu_delay = 1;
 
@@ -174,7 +193,6 @@ int main(_o_unused int argc, char* const argv[])
 	uint16_t opttype;
 	struct odhcp6c_opt *opt;
 	int ia_pd_iaid_index = 0;
-	int verbosity = 0;
 	bool help = false, daemonize = false;
 	int logopt = LOG_PID;
 	int c;
@@ -183,11 +201,12 @@ int main(_o_unused int argc, char* const argv[])
 	unsigned int ra_holdoff_interval = RA_MIN_ADV_INTERVAL;
 	ra_ifid_mode_t ra_ifid_mode = RA_IFID_LLA;
 	bool terminate = false;
+	bool deprecated_opt = false;
 
 	config_dhcp = config_dhcp_get();
 	config_dhcp_reset();
 
-	while ((c = getopt(argc, argv, "SDN:V:P:FB:c:i:r:Ru:Ux:s:EkK:t:C:m:Lhedp:fav")) != -1) {
+	while ((c = getopt(argc, argv, "SDN:V:P:FB:c:i:r:Ru:Ux:s:EkK:t:C:m:Lhedp:favl:")) != -1) {
 		switch (c) {
 		case 'S':
 			config_set_allow_slaac_only(false);
@@ -205,7 +224,7 @@ int main(_o_unused int argc, char* const argv[])
 		case 'V':
 			opt = odhcp6c_find_opt(DHCPV6_OPT_VENDOR_CLASS);
 			if (!opt) {
-				syslog(LOG_ERR, "Failed to set vendor-class option");
+				error("Failed to set vendor-class option");
 				return 1;
 			}
 
@@ -238,7 +257,7 @@ int main(_o_unused int argc, char* const argv[])
 				strncpy((char *)buf, optarg, optpos - optarg);
 				buf[optpos - optarg] = '\0';
 				if (inet_pton(AF_INET6, (char *)buf, &prefix.addr) <= 0) {
-					syslog(LOG_ERR, "invalid argument: '%s'", optarg);
+					error("invalid argument: '%s'", optarg);
 					return 1;
 				}
 				optpos++;
@@ -251,7 +270,7 @@ int main(_o_unused int argc, char* const argv[])
 			prefix.length = strtoul(optpos, &iaid_begin, 10);
 
 			if (*iaid_begin != '\0' && *iaid_begin != ',' && *iaid_begin != ':') {
-				syslog(LOG_ERR, "invalid argument: '%s'", optarg);
+				error("invalid argument: '%s'", optarg);
 				return 1;
 			}
 
@@ -263,7 +282,7 @@ int main(_o_unused int argc, char* const argv[])
 				prefix.iaid = htonl(++ia_pd_iaid_index);
 
 			if (odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix))) {
-				syslog(LOG_ERR, "Failed to set request IPv6-Prefix");
+				error("Failed to set request IPv6-Prefix");
 				return 1;
 			}
 			break;
@@ -280,7 +299,7 @@ int main(_o_unused int argc, char* const argv[])
 				buf[2] = 0;
 				buf[3] = l;
 				if (odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4)) {
-					syslog(LOG_ERR, "Failed to override client-ID");
+					error("Failed to override client-ID");
 					return 1;
 				} else {
 					client_id_param = true;
@@ -301,7 +320,7 @@ int main(_o_unused int argc, char* const argv[])
 				ifid.s6_addr[1] = 0x80;
 			} else {
 				/* Do not error on bad values; fall back to default */
-				syslog(LOG_ERR, "Invalid interface-ID: %s", optarg);
+				error("Invalid interface-ID: %s", optarg);
 			}
 			break;
 
@@ -315,7 +334,7 @@ int main(_o_unused int argc, char* const argv[])
 					optarg = &optpos[1];
 
 				if (odhcp6c_add_state(STATE_ORO, &opttype, 2)) {
-					syslog(LOG_ERR, "Failed to add requested option");
+					error("Failed to add requested option");
 					return 1;
 				}
 			}
@@ -328,7 +347,7 @@ int main(_o_unused int argc, char* const argv[])
 		case 'u':
 			opt = odhcp6c_find_opt(DHCPV6_OPT_USER_CLASS);
 			if (!opt) {
-				syslog(LOG_ERR, "Failed to set user-class option");
+				error("Failed to set user-class option");
 				return 1;
 			}
 
@@ -361,7 +380,7 @@ int main(_o_unused int argc, char* const argv[])
 
 		case 'E':
 #ifndef WITH_UBUS
-			syslog(LOG_ERR, "Failed to use ubus event: ENABLE_UBUS compilation flag missing");
+			error("Failed to use ubus event: ENABLE_UBUS compilation flag missing");
 			return 1;
 #endif /* WITH_UBUS */
 			script = NULL;
@@ -412,7 +431,12 @@ int main(_o_unused int argc, char* const argv[])
 			break;
 
 		case 'v':
-			++verbosity;
+			/* deprecated - remove -v options from start scripts first */
+			deprecated_opt = true;
+			break;
+
+		case 'l':
+			config_dhcp->log_level = (atoi(optarg) & LOG_PRIMASK);
 			break;
 
 		case 'x':
@@ -432,8 +456,7 @@ int main(_o_unused int argc, char* const argv[])
 	}
 
 	openlog("odhcp6c", logopt, LOG_DAEMON);
-	if (!verbosity)
-		setlogmask(LOG_UPTO(LOG_WARNING));
+	setlogmask(LOG_UPTO(config_dhcp->log_level));
 
 	ifname = argv[optind];
 
@@ -450,7 +473,7 @@ int main(_o_unused int argc, char* const argv[])
 	if (daemonize) {
 		openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 		if (daemon(0, 0)) {
-			syslog(LOG_ERR, "Failed to daemonize: %s",
+			error("Failed to daemonize: %s",
 					strerror(errno));
 			return 3;
 		}
@@ -465,12 +488,17 @@ int main(_o_unused int argc, char* const argv[])
 			fprintf(fp, "%i\n", getpid());
 			fclose(fp);
 		}
+	} else {
+		config_dhcp->log_syslog = false;
 	}
 
+	if (deprecated_opt)
+		warn("The -v flag is deprecated and will be removed. Use -l[0-7].");
+
 	if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 	    ra_init(ifname, &ifid, ra_ifid_mode, ra_options, ra_holdoff_interval) ||
 	    script_init(script, ifname)) {
-		syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
+		error("failed to initialize: %s", strerror(errno));
 		return 4;
 	}
 
@@ -487,14 +515,14 @@ int main(_o_unused int argc, char* const argv[])
 #ifdef WITH_UBUS
 	char *err = ubus_init(ifname);
 	if (err) {
-		syslog(LOG_ERR, "ubus error: %s", err);
+		error("ubus error: %s", err);
 		return 1;
 	}
 
 	struct ubus_context *ubus = ubus_get_ctx();
 	int ubus_socket = ubus->sock.fd;
 	if (ubus_socket < 0) {
-		syslog(LOG_ERR, "Invalid ubus file descriptor");
+		error("Invalid ubus file descriptor");
 		return 1;
 	}
 	fds[UBUS_FD_INDEX].fd = ubus_socket;
@@ -528,13 +556,13 @@ int main(_o_unused int argc, char* const argv[])
 			config_dhcp->oro_user_cnt = oro_len / sizeof(uint16_t);
 
 			if (init_dhcpv6(ifname)) {
-				syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
+				error("failed to initialize: %s", strerror(errno));
 				return 1;
 			}
 
 			fds[DHCPV6_FD_INDEX].fd = dhcpv6_get_socket();
 
-			syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
+			notice("(re)starting transaction on %s", ifname);
 
 			signal_usr1 = signal_usr2 = false;
 
@@ -587,12 +615,12 @@ int main(_o_unused int argc, char* const argv[])
 			if (!bound) {
 				bound = true;
 				if (mode == DHCPV6_STATELESS) {
-					syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
+					notice("entering stateless-mode on %s", ifname);
 					signal_usr1 = false;
 					notify_state_change("informed", script_sync_delay, true);
 				} else {
 					notify_state_change("bound", script_sync_delay, true);
-					syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
+					notice("entering stateful-mode on %s", ifname);
 				}
 			}
 
@@ -812,7 +840,7 @@ static int usage(void)
 	"	-p <pidfile>	Set pidfile (/var/run/odhcp6c.pid)\n"
 	"	-d		Daemonize\n"
 	"	-e		Write logmessages to stderr\n"
-	"	-v		Increase logging verbosity\n"
+	"	-l <level>	Set logging level (0-7)\n"
 	"	-h		Show this help\n\n";
 	fputs(buf, stderr);
 
diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index d022b24..bd3c515 100644
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -19,6 +19,7 @@
 #include <netinet/in.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <syslog.h>
 
 #ifndef _o_aligned
 #define _o_aligned(n) __attribute__((aligned(n)))
@@ -38,6 +39,16 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
+void __iflog(int lvl, const char *fmt, ...);
+#define debug(fmt, ...) __iflog(LOG_DEBUG, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define info(fmt, ...) __iflog(LOG_INFO, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define notice(fmt, ...) __iflog(LOG_NOTICE, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define warn(fmt, ...) __iflog(LOG_WARNING, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define error(fmt, ...) __iflog(LOG_ERR, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define critical(fmt, ...) __iflog(LOG_CRIT, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define alert(fmt, ...) __iflog(LOG_ALERT, fmt __VA_OPT__(, ) __VA_ARGS__)
+#define emergency(fmt, ...) __iflog(LOG_EMERG, fmt __VA_OPT__(, ) __VA_ARGS__)
+
 #define ND_OPT_RECURSIVE_DNS 25
 #define ND_OPT_DNSSL 31
 
diff --git a/src/ra.c b/src/ra.c
index 47343aa..40621d7 100644
--- a/src/ra.c
+++ b/src/ra.c
@@ -28,7 +28,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <syslog.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
 #include <sys/types.h>
@@ -231,7 +230,7 @@ static void ra_send_rs(_o_unused int signal)
 		len = sizeof(struct icmp6_hdr);
 
 	if (sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
-		syslog(LOG_ERR, "Failed to send RS (%s)",  strerror(errno));
+		error("Failed to send RS (%s)",  strerror(errno));
 
 	if (++rs_attempt <= 3)
 		alarm(4);
@@ -281,7 +280,7 @@ bool ra_link_up(void)
 	} while (read > 0);
 
 	if (ret) {
-		syslog(LOG_NOTICE, "carrier => %i event on %s", (int)!nocarrier, if_name);
+		notice("carrier => %i event on %s", (int)!nocarrier, if_name);
 
 		rs_attempt = 0;
 		ra_send_rs(SIGALRM);
@@ -363,7 +362,7 @@ static bool ra_generate_addr_eui64(void)
 
 	sock = socket(AF_INET6, SOCK_DGRAM, 0);
 	if (sock < 0) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: error creating EUI64 socket",
 		       if_name);
 		return false;
@@ -373,7 +372,7 @@ static bool ra_generate_addr_eui64(void)
 	strncpy(ifr.ifr_name, if_name, sizeof(ifr.ifr_name) - 1);
 
 	if (ioctl(sock, SIOCGIFHWADDR, &ifr) != 0) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: error getting EUI64 HW address",
 		       if_name);
 		close(sock);
@@ -383,7 +382,7 @@ static bool ra_generate_addr_eui64(void)
 	close(sock);
 
 	if (!odhcp6c_is_valid_ether_addr((uint8_t *) ifr.ifr_hwaddr.sa_data)) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: invalid EUI64 HW address",
 		       if_name);
 		return false;
@@ -411,14 +410,14 @@ static bool ra_generate_addr_ll(void)
 
 	sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
 	if (sock < 0) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: error creating LLA socket",
 		       if_name);
 		return false;
 	}
 
 	if (connect(sock, (struct sockaddr*) &addr, sizeof(addr)) != 0) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: error connecting LLA socket",
 		       if_name);
 		close(sock);
@@ -426,7 +425,7 @@ static bool ra_generate_addr_ll(void)
 	}
 
 	if (getsockname(sock, (struct sockaddr*) &addr, &alen) != 0) {
-		syslog(LOG_ERR,
+		error(
 		       "%s: error getting address from LLA socket",
 		       if_name);
 		close(sock);
@@ -445,7 +444,7 @@ static bool ra_generate_addr_rand(void)
 	if (odhcp6c_random(&ra_addr.s6_addr[8], 8) != 8) {
 		ra_addr.s6_addr32[2] = 0;
 		ra_addr.s6_addr32[3] = 0;
-		syslog(LOG_ERR,
+		error(
 		       "%s: error generating random interface address",
 		       if_name);
 		return false;
diff --git a/src/script.c b/src/script.c
index 209f7ee..8621d98 100644
--- a/src/script.c
+++ b/src/script.c
@@ -22,7 +22,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <syslog.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
@@ -500,7 +499,7 @@ void script_call(const char *status, int delay, bool resume)
 		if (capt_port_ra_len > 0 && capt_port_dhcpv6_len > 0) {
 			if (capt_port_ra_len != capt_port_dhcpv6_len ||
 				!memcmp(capt_port_dhcpv6, capt_port_ra, capt_port_dhcpv6_len))
-				syslog(LOG_ERR,
+				error(
 					"%s received via different vectors differ: preferring URI from DHCPv6",
 					CAPT_PORT_URI_STR);
 		}
diff --git a/src/ubus.c b/src/ubus.c
index 44349e8..3530f33 100644
--- a/src/ubus.c
+++ b/src/ubus.c
@@ -65,7 +65,6 @@
 #include <resolv.h>
 #include <stdio.h>
 #include <sys/types.h>
-#include <syslog.h>
 
 #include "config.h"
 #include "odhcp6c.h"
@@ -76,7 +75,7 @@
 		int ret = (stmt); \
 		if (ret != UBUS_STATUS_OK) \
 		{ \
-			syslog(LOG_ERR, "%s failed: %s (%d)", #stmt, ubus_strerror(ret), ret); \
+			error("%s failed: %s (%d)", #stmt, ubus_strerror(ret), ret); \
 			return ret; \
 		} \
 	} while (0)
@@ -195,7 +194,7 @@ static void ubus_disconnect_cb(struct ubus_context *ubus)
 
 	ret = ubus_reconnect(ubus, NULL);
 	if (ret) {
-		syslog(LOG_ERR, "Cannot reconnect to ubus: %s", ubus_strerror(ret));
+		error("Cannot reconnect to ubus: %s", ubus_strerror(ret));
 		ubus_destroy(ubus);
 	}
 }
@@ -227,7 +226,7 @@ struct ubus_context *ubus_get_ctx(void)
 
 void ubus_destroy(struct ubus_context *ubus)
 {
-	syslog(LOG_NOTICE, "Disconnecting from ubus");
+	notice("Disconnecting from ubus");
 
 	if (ubus != NULL)
 		ubus_free(ubus);
@@ -565,7 +564,7 @@ static int states_to_blob(void)
 	if (capt_port_ra_len > 0 && capt_port_dhcpv6_len > 0) {
 		if (capt_port_ra_len != capt_port_dhcpv6_len ||
 			!memcmp(capt_port_dhcpv6, capt_port_ra, capt_port_dhcpv6_len))
-			syslog(LOG_ERR,
+			error(
 				"%s received via different vectors differ: preferring URI from DHCPv6",
 				CAPT_PORT_URI_STR);
 	}