udyfi

commit 8adb0d2527090e48add742b8dad32a4ecf837775
parent c3fbeeeae176034b869f84d283953edaf89ecf91
Author: Santtu Lakkala <inz@inz.fi>
Date:   Wed,  5 Jul 2023 20:12:45 +0300

Refactor and add no-ip.com support

 - Handle common HTTP error codes and act appropriately
 - Add handling for no-ip.com error codes
 - Re-check IP on SIGHUP
 - Handle SIGINT and SIGTERM in any state
 - Add user-agent

Diffstat:
M
Makefile
 | 
10
++++++++--
A
config.def.h
 | 
18
++++++++++++++++++
M
udyfi.c
 | 
236
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------------

3 files changed, 209 insertions(+), 55 deletions(-)
diff --git a/Makefile b/Makefile
@@ -3,7 +3,8 @@ CFLAGS += -W -Wall -std=c99 -pedantic -D_POSIX_C_SOURCE=200809L
 PREFIX ?= /usr/local
 BINDIR := $(PREFIX)/bin
 IFADDRS_CFLAGS ?= -DUSE_IFADDRS
-HEADERS = arg.h
+HEADERS = arg.h config.h
+VERSION=0.1.0
 
 LIBTLS_CFLAGS += -DUSE_LIBTLS -I/usr/local/include
 LIBS := -L/usr/local/lib -ltls
@@ -11,10 +12,15 @@ LIBS := -L/usr/local/lib -ltls
 #OPENSSL_CFLAGS += $(shell pkg-config openssl --cflags && echo -DUSE_OPENSSL)
 #LIBS := $(shell pkg-config openssl --libs)
 #HEADERS += minitls.h
+
 all: udyfi
 
+config.h: config.def.h
+	if test -f "$@"; then echo "Refusing to overwrite old config.h"; false; fi
+	cp $< $@
+
 udyfi: udyfi.c $(HEADERS)
-	$(CROSS)$(CC) $(CFLAGS) $(LIBTLS_CFLAGS) $(OPENSSL_CFLAGS) $(IFADDRS_CFLAGS) $< -o $@ $(LIBS)
+	$(CROSS)$(CC) -DVERSION='"$(VERSION)"' $(CFLAGS) $(LIBTLS_CFLAGS) $(OPENSSL_CFLAGS) $(IFADDRS_CFLAGS) $< -o $@ $(LIBS)
 
 clean:
 	rm -f udyfi
diff --git a/config.def.h b/config.def.h
@@ -0,0 +1,18 @@
+static const time_t minimum_refresh = DAYS(5);
+static const time_t minimum_refresh_rand = HOURS(10);
+
+static const time_t check_interval = MINUTES(4);
+static const time_t check_interval_rand = MINUTES(2);
+
+static const time_t error_fallback = MINUTES(30);
+static const time_t error_fallback_rand = MINUTES(5);
+
+static const char *checkip_service = "checkip.dy.fi";
+static const char *checkip_port = "80";
+IF_SSL(static bool checkip_ssl = false;)
+
+static const char *dyndns_service = "dy.fi";
+static const char *dyndns_port = "80";
+IF_SSL(static bool dyndns_ssl = true;)
+
+static const char *default_ua = "udyfi/" VERSION " inz@inz.fi";
diff --git a/udyfi.c b/udyfi.c
@@ -25,6 +25,7 @@
 #undef __BSD_VISIBLE
 #define __BSD_VISIBLE 1
 #include <sys/socket.h>
+#include <sys/select.h>
 #include <signal.h>
 #include <poll.h>
 #include <fcntl.h>
@@ -37,6 +38,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdbool.h>
+#include <limits.h>
 #ifdef USE_IFADDRS
 #define __USE_MISC
 #include <net/if.h>
@@ -52,18 +54,6 @@
 #endif
 #include "arg.h"
 
-static const time_t minimum_refresh = 5 * 24 * 60 * 60;
-static const time_t minimum_refresh_rand = 10 * 60 * 60;
-
-static const time_t check_interval = 4 * 60;
-static const time_t check_interval_rand = 2 * 60;
-
-static const char *checkip_service = "checkip.dy.fi";
-static const char *checkip_port = "80";
-
-static const char *dyndns_service = "dy.fi";
-static const char *dyndns_port = "80";
-
 static bool running = true;
 char *argv0;
 
@@ -73,6 +63,11 @@ char *argv0;
 #define IF_SSL(...)
 #endif
 
+#define MINUTES(x) ((x) * 60)
+#define HOURS(x) (MINUTES(x) * 60)
+#define DAYS(x) (HOURS(x) * 24)
+#include "config.h"
+
 static char **strsplit(char *s, int *c)
 {
 	size_t n = 1;
@@ -138,7 +133,7 @@ static void sighup_handler(int signum)
 static ssize_t http_get(const char *server,
 			const char *port,
 			const char *path,
-			const char *headers,
+			const char * restrict headers,
 			const char *iface,
 			int *af,
 			char *buffer,
@@ -208,7 +203,7 @@ static ssize_t http_get(const char *server,
 #if USE_IFADDRS
 		if (addrs) {
 			for (j = addrs; j; j = j->ifa_next) {
-				if (!strcmp(j->ifa_name, iface) && 
+				if (!strcmp(j->ifa_name, iface) &&
 				    (((j->ifa_flags & (IFF_UP |
 						       IFF_BROADCAST |
 						       IFF_LOOPBACK)) ==
@@ -261,6 +256,8 @@ static ssize_t http_get(const char *server,
 		return -1;
 	}
 
+	printf("%s\n", buffer);
+
 #ifdef USE_LIBTLS
 	if (ctx) {
 		if (tls_connect_socket(ctx, sock, server)) {
@@ -282,6 +279,10 @@ static ssize_t http_get(const char *server,
 		return -1;
 	}
 
+
+	if (!running)
+		return -1;
+
 	s = 0;
 	do {
 #ifdef USE_LIBTLS
@@ -291,10 +292,14 @@ static ssize_t http_get(const char *server,
 #endif
 		r = read(sock, buffer + s, bufsize - s - 1);
 		if (r < 0) {
+			if (!running)
+				return -1;
 #ifdef USE_LIBTLS
 			if (ctx) {
 				if (r == TLS_WANT_POLLIN) {
 					poll(&(struct pollfd){ .fd = sock, .events = POLLIN }, 1, 0);
+					if (!running)
+						return -1;
 					continue;
 				}
 
@@ -321,21 +326,49 @@ static ssize_t http_get(const char *server,
 	return s;
 }
 
+static char *add_header(char *buffer, char *buf_end, const char *name, const char *value) {
+	static const char sep[2] = ": ";
+	static const char end[2] = "\r\n";
+	size_t nl;
+	size_t vl;
+
+	if (!buffer)
+		return NULL;
+
+	nl = strlen(name);
+	vl = strlen(value);
+
+	if (buffer + nl + vl + sizeof(sep) + sizeof(end) >= buf_end)
+		return NULL;
+	buffer = (char *)memcpy(buffer, name, nl) + nl;
+	buffer = (char *)memcpy(buffer, sep, sizeof(sep)) + sizeof(sep);
+	buffer = (char *)memcpy(buffer, value, vl) + vl;
+	buffer = (char *)memcpy(buffer, end, sizeof(end)) + sizeof(end);
+	*buffer = '\0';
+
+	return buffer;
+}
+
 static int check_ip(const char *server,
 		    const char *port,
 		    const char *iface,
 		    int af,
+		    const char *ua,
 		    char *ip_buffer,
 		    size_t ip_size
 		    IF_SSL(, struct tls *ctx)
 		   )
 {
+	char header_buffer[1024];
 	char buffer[1024];
 	const char *ip;
 	size_t iplen;
 
+	if (!add_header(header_buffer, 1[&header_buffer], "User-Agent", ua))
+		return -1;
+
 	if (http_get(server, port, "/",
-		     NULL,
+		     header_buffer,
 		     iface,
 		     &af,
 		     buffer,
@@ -344,11 +377,13 @@ static int check_ip(const char *server,
 		     ) < 0)
 		return -1;
 
-	ip = strstr(buffer, "Current IP Address: ");
-	if (!ip)
+	if ((ip = strstr(buffer, "Current IP Address: ")))
+		ip += sizeof("Current IP Address: ") - 1;
+	else if ((ip = strstr(buffer, "\r\n\r\n")))
+		ip += sizeof("\r\n\r\n") - 1;
+	else
 		return -1;
 
-	ip += sizeof("Current IP Address: ") - 1;
 	switch (af) {
 	case AF_INET:
 	default:
@@ -360,6 +395,8 @@ static int check_ip(const char *server,
 	}
 	if (iplen > ip_size)
 		return -1;
+	if (ip == buffer && ip[iplen])
+		return -1;
 	sprintf(ip_buffer, "%.*s", (int)iplen, ip);
 
 	return 0;
@@ -438,7 +475,10 @@ enum update_status {
 	UP_GOOD,
 	UP_DNSERR,
 	UP_ABUSE,
+	UP_BADAGENT,
+	UP_911,
 	UP_UNKNOWN,
+	UP_REDIRECT,
 	UP_INTERNAL,
 	UP_NETWORK
 };
@@ -451,52 +491,87 @@ static const char *statusstr[] = {
 	"nochg",
 	"good ",
 	"dnserr",
-	"abuse"
+	"abuse",
+	"badagent",
+	"911"
 };
 
+static unsigned short http_code(const char *buffer, const char *bend)
+{
+	const char match[] = "HTTP/1.";
+	unsigned int rv = 0;
+
+	if (buffer + sizeof(match) >= bend || memcmp(buffer, match, sizeof(match) - 1))
+		return 0;
+	buffer += sizeof(match);
+	if (buffer[-1] != '0' && buffer[-1] != '1')
+		return 0;
+	if (buffer >= bend || *buffer++ != ' ')
+		return 0;
+	for (; buffer < bend; buffer++) {
+		if (*buffer == ' ')
+			break;
+		if (*buffer >= '0' && *buffer <= '9')
+			rv = rv * 10 + (*buffer - '0');
+		else
+			return 0;
+
+		if (rv > USHRT_MAX)
+			return 0;
+	}
+
+	return rv;
+}
+
 static int update_ip(const char *server,
 		     const char *port,
 		     const char *hosts,
-		     const char *username,
-		     const char *password,
+		     const char *auth,
 		     const char *iface,
-		     int af
+		     int af,
+		     const char *ua
 		     IF_SSL(, struct tls *ctx)
 		     )
 {
 	char buffer[1024];
-	char auth_buffer[1024];
 	char path_buffer[1024];
-	int pos;
+	char header_buffer[1024];
 	int r;
 	size_t bl;
 	const char *body;
+	unsigned short code;
+	char *bend = 1[&header_buffer];
 
-	pos = snprintf(auth_buffer, sizeof(auth_buffer),
-		       "Authorization: Basic ");
-	if (pos >= (int)sizeof(auth_buffer))
-		return UP_INTERNAL;
-	if ((r = auth_token(username, password,
-			    auth_buffer + pos, sizeof(auth_buffer) - pos)) < 0)
-		return UP_INTERNAL;
-	pos += r;
-	pos += snprintf(auth_buffer + pos, sizeof(auth_buffer) - pos,
-			"\r\n");
-	if (pos >= (int)sizeof(auth_buffer))
+	char *bpos = add_header(header_buffer, bend, "User-Agent", ua);
+	bpos = add_header(bpos, bend, "Authorization", auth);
+
+	if (!bpos)
 		return UP_INTERNAL;
 
-	pos = snprintf(path_buffer, sizeof(path_buffer),
+	r = snprintf(path_buffer, sizeof(path_buffer),
 		       "/nic/update?hostname=%s", hosts);
-	if (pos >= (int)sizeof(path_buffer))
+	if (r >= (int)sizeof(path_buffer))
 		return UP_INTERNAL;
 
 	if ((r = http_get(server, port, path_buffer,
-			  auth_buffer, iface, &af,
+			  header_buffer, iface, &af,
 			  buffer, sizeof(buffer)
 		          IF_SSL(, ctx)
 		     )) < 0)
 		return UP_NETWORK;
 
+	code = http_code(buffer, buffer + strlen(buffer));
+	if (!code || code >= 500)
+		return UP_911;
+	if (code == 401)
+		return UP_BADAUTH;
+	if (code == 403)
+		return UP_NOHOST;
+	if (code > 400)
+		return UP_UNKNOWN;
+	if (code >= 300)
+		return UP_REDIRECT;
+
 	if ((body = find_body(buffer, r,
 			     &bl))) {
 		for (r = 0; r < UP_UNKNOWN; r++) {
@@ -533,6 +608,8 @@ static void usage(void) {
 		IF_SSL(
 		"[-s] "
 		"[-S] "
+		"[-z] "
+		"[-Z] "
 		)
 		"[-6] "
 		"[-4] "
@@ -571,9 +648,12 @@ int main(int argc, char **argv)
 	const char *iface = NULL;
 	const char *dropuser = NULL;
 	const char *domains = NULL;
+	const char *ua = default_ua;
 	char password[256] = "";
+	char authbuf[1024] = "Basic ";
 	int fd;
 	time_t next_refresh = 0;
+	time_t last_error = 0;
 	char ipbuf1[64];
 	char ipbuf2[64] = "";
 	char *ip = ipbuf1;
@@ -584,6 +664,9 @@ int main(int argc, char **argv)
 	FILE *log = stderr;
 	const char *logfile = NULL;
 	char *arg;
+	sigset_t sigset_all;
+	sigset_t sigset_hup;
+	sigset_t sigset_dfl;
 
 	struct {
 		char **argv;
@@ -594,11 +677,19 @@ int main(int argc, char **argv)
 #ifdef USE_LIBTLS
 	int port_set = 0;
 	int check_port_set = 0;
-	int use_ssl = 0;
-	int check_ssl = 0;
+	bool use_ssl = dyndns_ssl;
+	bool check_ssl = checkip_ssl;
 	struct tls *ctx = NULL;
 #endif
 
+	sigemptyset(&sigset_all);
+	sigaddset(&sigset_all, SIGHUP);
+	sigaddset(&sigset_all, SIGTERM);
+	sigaddset(&sigset_all, SIGINT);
+
+	sigemptyset(&sigset_hup);
+	sigaddset(&sigset_hup, SIGHUP);
+
 	for (argv0 = *argv, argv++, argc--;
 	     argc && argv[0][0] == '-' && argv[0][1];
 	     argc--, argv++) {
@@ -613,6 +704,9 @@ cfgtoggle:
 
 		while (*arg) {
 			switch (*arg++) {
+			case 'a':
+				ua = EARGF(usage());
+				break;
 			case 'i':
 				iface = EARGF(usage());
 				break;
@@ -721,10 +815,16 @@ cfgtoggle:
 				  break;
 #ifdef USE_LIBTLS
 			case 's':
-				  use_ssl = 1;
+				  use_ssl = true;
 				  break;
 			case 'S':
-				  check_ssl = 1;
+				  check_ssl = true;
+				  break;
+			case 'z':
+				  use_ssl = false;
+				  break;
+			case 'Z':
+				  check_ssl = false;
 				  break;
 #endif
 			default:
@@ -767,6 +867,9 @@ cfgtoggle:
 		return EXIT_FAILURE;
 	}
 
+	auth_token(username, password, authbuf + strlen(authbuf), sizeof(authbuf) - strlen(authbuf));
+	memset(password, 0, sizeof(password));
+
 	srand(time(NULL));
 
 	if (logfile)
@@ -799,10 +902,13 @@ cfgtoggle:
 	signal(SIGTERM, sig_handler);
 	sigaction(SIGHUP, &(struct sigaction){ .sa_handler = sighup_handler }, NULL);
 
+	sigprocmask(SIG_BLOCK, &sigset_hup, &sigset_dfl);
+
 	while (running) {
 		time_t now = time(NULL);
 
-		if (check_ip(checkip_service, checkip_port, iface, af,
+		if (now >= last_error + error_fallback &&
+		    check_ip(checkip_service, checkip_port, iface, af, ua,
 			     ip, sizeof(ipbuf1)
 			     IF_SSL(, check_ssl ? ctx : NULL)
 			     ) >= 0) {
@@ -811,7 +917,7 @@ cfgtoggle:
 			if ((strcmp(ip, prev_ip) || now > next_refresh)) {
 				switch (update_ip(dyndns_service, dyndns_port,
 						  domains,
-						  username, password, iface, af
+						  authbuf, iface, af, ua
 						  IF_SSL(, use_ssl ? ctx : NULL)
 						 )) {
 				case UP_BADAUTH:
@@ -841,19 +947,31 @@ cfgtoggle:
 					fprintf(log, "%s now point to %s\n",
 						domains, ip);
 					break;
+				case UP_911:
 				case UP_DNSERR:
 					fprintf(log, "WARNING: "
 						"Temporary service error\n");
-					break;
+					last_error = now;
+					goto retry;
 				case UP_ABUSE:
 					fprintf(log, "FATAL: "
 						"We are flagged as abuse\n");
 					ret = EXIT_FAILURE;
 					goto out;
+				case UP_BADAGENT:
+					fprintf(log, "FATAL: "
+						"We are flagged as bad agent\n");
+					ret = EXIT_FAILURE;
+					goto out;
 				case UP_UNKNOWN:
 					fprintf(log, "WARNING: "
 						"Unknown status reply\n");
 					break;
+				case UP_REDIRECT:
+					fprintf(log, "FATAL: "
+						"Server send a redirection, configuration error?\n");
+					ret = EXIT_FAILURE;
+					goto out;
 				case UP_INTERNAL:
 					fprintf(log, "FATAL: "
 						"Internal error, likely run "
@@ -861,9 +979,11 @@ cfgtoggle:
 					ret = EXIT_FAILURE;
 					goto out;
 				case UP_NETWORK:
+					if (!running)
+						goto out;
 					fprintf(log, "WARNING: "
 						"Networking error\n");
-					break;
+					goto retry;
 				}
 
 				next_refresh = now + minimum_refresh +
@@ -872,18 +992,28 @@ cfgtoggle:
 				fprintf(log, "Next forced update at %s",
 					ctime(&next_refresh));
 				fflush(log);
-			}
 
-			tmp = ip;
-			ip = prev_ip;
-			prev_ip = tmp;
-		} else {
+				tmp = ip;
+				ip = prev_ip;
+				prev_ip = tmp;
+			}
+		} else if (running) {
 			fprintf(log, "IP check failed.\n");
 			fflush(log);
 		}
 
-		sleep(check_interval +
-		      rand() * check_interval_rand / RAND_MAX);
+retry:
+		sigprocmask(SIG_BLOCK, &sigset_all, NULL);
+		if (!running)
+			break;
+
+		pselect(0, NULL, NULL, NULL, &(struct timespec){
+			.tv_sec = (last_error + error_fallback < now ?
+				   check_interval + rand() * check_interval_rand / RAND_MAX :
+				   last_error + error_fallback - now + rand() * error_fallback_rand / RAND_MAX)
+			}, &sigset_dfl);
+
+		sigprocmask(SIG_BLOCK, &sigset_hup, NULL);
 	}
 
 out: