Improve generic ipv4+ipv6 support in libbb.

Convert telnet to it. Now this works:
telnetd -b [::1]:1234 - bind to IPv6 non-standard port
telnet [::1]:1234 - connect to IPv6 non-standard port
telnet ::1 1234 - same
This does not require ANY ipv6-specific code in applets
(no struct sockaddr_in6. In fact, no sockaddr_in, too).

4 files changed, 172 insertions, 116 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 6f66c85..16f092f 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -293,18 +293,17 @@ extern void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen);
 extern int xconnect_tcp_v4(struct sockaddr_in *s_addr);
 extern struct hostent *xgethostbyname(const char *name);
 extern struct hostent *xgethostbyname2(const char *name, int af);
-extern int xsocket_stream_ip4or6(sa_family_t *fp);
-typedef union {
-	struct sockaddr sa;
-	struct sockaddr_in sin;
-#if ENABLE_FEATURE_IPV6
-	struct sockaddr_in6 sin6;
-#endif
-} sockaddr_inet;
-extern int dotted2sockaddr(const char *dotted, struct sockaddr* sp, int socklen);
-extern int create_and_bind_socket_ip4or6(const char *hostaddr, int port);
+
 extern int setsockopt_reuseaddr(int fd);
 extern int setsockopt_broadcast(int fd);
+/* Create server TCP socket bound to bindaddr:port. bindaddr can be NULL,
+ * numeric IP ("N.N.N.N") or numeric IPv6 address,
+ * and can have ":PORT" suffix. If no suffix trere, second argument is used */
+extern int create_and_bind_stream_or_die(const char *bindaddr, int port);
+/* Create client TCP socket connected to peer:port. Peer cannot be NULL.
+ * Peer can be numeric IP ("N.N.N.N"), numeric IPv6 address or hostname,
+ * and can have ":PORT" suffix. If no suffix trere, second argument is used */
+extern int create_and_connect_stream_or_die(const char *peer, int def_port);
 
 
 extern char *xstrdup(const char *s);
@@ -506,7 +505,7 @@ USE_DESKTOP(long long) int uncompress(int fd_in, int fd_out);
 int inflate(int in, int out);
 
 
-unsigned short bb_lookup_port(const char *port, const char *protocol, unsigned short default_port);
+unsigned bb_lookup_port(const char *port, const char *protocol, unsigned default_port);
 void bb_lookup_host(struct sockaddr_in *s_in, const char *host);
 
 int bb_make_directory(char *path, long mode, int flags);
diff --git a/libbb/xconnect.c b/libbb/xconnect.c
index bc06915..93c3cd5 100644
--- a/libbb/xconnect.c
+++ b/libbb/xconnect.c
@@ -6,39 +6,62 @@
  *
  */
 
+#include <netinet/in.h>
 #include "libbb.h"
 
+static const int one = 1;
+int setsockopt_reuseaddr(int fd)
+{
+	return setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+}
+int setsockopt_broadcast(int fd)
+{
+	return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one));
+}
+
+void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
+{
+	if (connect(s, s_addr, addrlen) < 0) {
+		if (ENABLE_FEATURE_CLEAN_UP)
+			close(s);
+		if (s_addr->sa_family == AF_INET)
+			bb_perror_msg_and_die("%s (%s)",
+				"cannot connect to remote host",
+				inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
+		bb_perror_msg_and_die("cannot connect to remote host");
+	}
+}
+
 /* Return network byte ordered port number for a service.
  * If "port" is a number use it as the port.
  * If "port" is a name it is looked up in /etc/services, if it isnt found return
- * default_port
- */
-unsigned short bb_lookup_port(const char *port, const char *protocol, unsigned short default_port)
+ * default_port */
+unsigned bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
 {
-	unsigned short port_nr = htons(default_port);
+	unsigned port_nr = htons(default_port);
 	if (port) {
-		char *endptr;
 		int old_errno;
-		long port_long;
 
 		/* Since this is a lib function, we're not allowed to reset errno to 0.
 		 * Doing so could break an app that is deferring checking of errno. */
 		old_errno = errno;
-		errno = 0;
-		port_long = strtol(port, &endptr, 10);
-		if (errno != 0 || *endptr!='\0' || endptr==port || port_long < 0 || port_long > 65535) {
+		port_nr = bb_strtou(port, NULL, 10);
+		if (errno || port_nr > 65535) {
 			struct servent *tserv = getservbyname(port, protocol);
-			if (tserv) {
+			if (tserv)
 				port_nr = tserv->s_port;
-			}
 		} else {
-			port_nr = htons(port_long);
+			port_nr = htons(port_nr);
 		}
 		errno = old_errno;
 	}
 	return port_nr;
 }
 
+
+/* "Old" networking API - only IPv4 */
+
+
 void bb_lookup_host(struct sockaddr_in *s_in, const char *host)
 {
 	struct hostent *he;
@@ -49,18 +72,6 @@ void bb_lookup_host(struct sockaddr_in *s_in, const char *host)
 	memcpy(&(s_in->sin_addr), he->h_addr_list[0], he->h_length);
 }
 
-void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
-{
-	if (connect(s, s_addr, addrlen) < 0) {
-		if (ENABLE_FEATURE_CLEAN_UP) close(s);
-		if (s_addr->sa_family == AF_INET)
-			bb_perror_msg_and_die("%s (%s)",
-				"cannot connect to remote host",
-				inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
-		bb_perror_msg_and_die("cannot connect to remote host");
-	}
-}
-
 int xconnect_tcp_v4(struct sockaddr_in *s_addr)
 {
 	int s = xsocket(AF_INET, SOCK_STREAM, 0);
@@ -68,87 +79,144 @@ int xconnect_tcp_v4(struct sockaddr_in *s_addr)
 	return s;
 }
 
-static const int one = 1;
-int setsockopt_reuseaddr(int fd)
-{
-	return setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
-}
-int setsockopt_broadcast(int fd)
-{
-	return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one));
-}
 
-int dotted2sockaddr(const char *dotted, struct sockaddr* sp, int socklen)
-{
-	union {
-		struct in_addr a4;
-#if ENABLE_FEATURE_IPV6
-		struct in6_addr a6;
-#endif
-	} a;
+/* "New" networking API */
 
-	/* TODO maybe: port spec? like n.n.n.n:nn */
 
+/* So far we do not expose struct and helpers to libbb */
+typedef struct len_and_sockaddr {
+	int len;
+	union {
+		struct sockaddr sa;
+		struct sockaddr_in sin;
 #if ENABLE_FEATURE_IPV6
-	if (socklen >= sizeof(struct sockaddr_in6)
-	 && inet_pton(AF_INET6, dotted, &a.a6) > 0
-	) {
-		((struct sockaddr_in6*)sp)->sin6_family = AF_INET6;
-		((struct sockaddr_in6*)sp)->sin6_addr = a.a6;
-		/* ((struct sockaddr_in6*)sp)->sin6_port = */
-		return 0; /* success */
-	}
+		struct sockaddr_in6 sin6;
 #endif
-	if (socklen >= sizeof(struct sockaddr_in)
-	 && inet_pton(AF_INET, dotted, &a.a4) > 0
-	) {
-		((struct sockaddr_in*)sp)->sin_family = AF_INET;
-		((struct sockaddr_in*)sp)->sin_addr = a.a4;
-		/* ((struct sockaddr_in*)sp)->sin_port = */
-		return 0; /* success */
+	};
+} len_and_sockaddr;
+//extern int xsocket_stream_ip4or6(sa_family_t *fp);
+//extern len_and_sockaddr* host2sockaddr(const char *host, int def_port);
+//extern len_and_sockaddr* dotted2sockaddr(const char *dotted, int def_port);
+
+/* peer: "1.2.3.4[:port]", "www.google.com[:port]"
+ * def_port: if neither of above specifies port #
+ */
+static len_and_sockaddr* str2sockaddr(const char *host, int def_port, int ai_flags)
+{
+	int rc;
+	len_and_sockaddr *r; // = NULL;
+	struct addrinfo *result = NULL;
+	const char *org_host = host; /* only for error msg */
+	const char *cp;
+	char service[sizeof(int)*3 + 1];
+	struct addrinfo hint;
+
+	/* Ugly parsing of host:addr */
+	if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
+		host++;
+		cp = strchr(host, ']');
+		if (!cp || cp[1] != ':') /* Malformed: must have [xx]:nn */
+			bb_error_msg_and_die("bad address '%s'", org_host);
+			//return r; /* return NULL */
+	} else {
+		cp = strrchr(host, ':');
+		if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
+			/* There is more than one ':' (e.g. "::1") */
+			cp = NULL; /* it's not a port spec */
+		}
 	}
-	return 1;
+	if (cp) {
+		host = safe_strncpy(alloca(cp - host + 1), host, cp - host);
+		if (ENABLE_FEATURE_IPV6 && *cp != ':')
+			cp++; /* skip ']' */
+		cp++; /* skip ':' */
+	} else {
+		utoa_to_buf(def_port, service, sizeof(service));
+		cp = service;
+	}
+
+	memset(&hint, 0 , sizeof(hint));
+	/* hint.ai_family = AF_UNSPEC; - zero anyway */
+#if !ENABLE_FEATURE_IPV6
+	hint.ai_family = AF_INET; /* do not try to find IPv6 */
+#endif
+	/* Needed. Or else we will get each address thrice (or more)
+	 * for each possible socket type (tcp,udp,raw...): */
+	hint.ai_socktype = SOCK_STREAM;
+	hint.ai_flags = ai_flags | AI_NUMERICSERV;
+	rc = getaddrinfo(host, cp, &hint, &result);
+	if (rc || !result)
+		bb_error_msg_and_die("bad address '%s'", org_host);
+	r = xmalloc(offsetof(len_and_sockaddr, sa) + result->ai_addrlen);
+	r->len = result->ai_addrlen;
+	memcpy(&r->sa, result->ai_addr, result->ai_addrlen);
+	freeaddrinfo(result);
+	return r;
+}
+
+static len_and_sockaddr* host2sockaddr(const char *host, int def_port)
+{
+	return str2sockaddr(host, def_port, 0);
+}
+
+static len_and_sockaddr* dotted2sockaddr(const char *host, int def_port)
+{
+	return str2sockaddr(host, def_port, NI_NUMERICHOST);
 }
 
-int xsocket_stream_ip4or6(sa_family_t *fp)
+static int xsocket_stream_ip4or6(len_and_sockaddr *lsa)
 {
 	int fd;
 #if ENABLE_FEATURE_IPV6
 	fd = socket(AF_INET6, SOCK_STREAM, 0);
-	if (fp) *fp = AF_INET6;
-	if (fd < 0)
+	lsa->sa.sa_family = AF_INET6;
+	lsa->len = sizeof(struct sockaddr_in6);
+	if (fd >= 0)
+		return fd;
 #endif
-	{
-		fd = xsocket(AF_INET, SOCK_STREAM, 0);
-		if (fp) *fp = AF_INET;
-	}
+	fd = xsocket(AF_INET, SOCK_STREAM, 0);
+	lsa->sa.sa_family = AF_INET;
+	lsa->len = sizeof(struct sockaddr_in);
 	return fd;
 }
 
-int create_and_bind_socket_ip4or6(const char *hostaddr, int port)
+int create_and_bind_stream_or_die(const char *bindaddr, int port)
 {
 	int fd;
-	sockaddr_inet sa;
+	len_and_sockaddr *lsa;
 
-	memset(&sa, 0, sizeof(sa));
-	if (hostaddr) {
-		if (dotted2sockaddr(hostaddr, &sa.sa, sizeof(sa)))
-			bb_error_msg_and_die("bad address '%s'", hostaddr);
+	if (bindaddr) {
+		lsa = dotted2sockaddr(bindaddr, port);
+		/* currently NULL check is in str2sockaddr */
+		//if (!lsa)
+		//	bb_error_msg_and_die("bad address '%s'", bindaddr);
 		/* user specified bind addr dictates family */
-		fd = xsocket(sa.sa.sa_family, SOCK_STREAM, 0);
-	} else 
-		fd = xsocket_stream_ip4or6(&sa.sa.sa_family);
+		fd = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0);
+	} else {
+		lsa = xzalloc(offsetof(len_and_sockaddr, sa) +
+			USE_FEATURE_IPV6(sizeof(struct sockaddr_in6))
+			SKIP_FEATURE_IPV6(sizeof(struct sockaddr_in))
+		);
+		fd = xsocket_stream_ip4or6(lsa);
+	}
 	setsockopt_reuseaddr(fd);
+	xbind(fd, &lsa->sa, lsa->len);
+	free(lsa);
+	return fd;
+}
 
-	/* if (port >= 0) { */
-#if ENABLE_FEATURE_IPV6
-		if (sa.sa.sa_family == AF_INET6 /* && !sa.sin6.sin6_port */)
-			sa.sin6.sin6_port = htons(port);
-#endif
-		if (sa.sa.sa_family == AF_INET /* && !sa.sin.sin_port */)
-			sa.sin.sin_port = htons(port);
-	/* } */
+int create_and_connect_stream_or_die(const char *peer, int port)
+{
+	int fd;
+	len_and_sockaddr *lsa;
 
-	xbind(fd, &sa.sa, sizeof(sa));
+	lsa = host2sockaddr(peer, port);
+	/* currently NULL check is in str2sockaddr */
+	//if (!lsa)
+	//	bb_error_msg_and_die("bad address '%s'", peer);
+	fd = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0);
+	setsockopt_reuseaddr(fd);
+	xconnect(fd, &lsa->sa, lsa->len);
+	free(lsa);
 	return fd;
 }
diff --git a/networking/telnet.c b/networking/telnet.c
index e65b691..5ca64e1 100644
--- a/networking/telnet.c
+++ b/networking/telnet.c
@@ -22,15 +22,7 @@
  */
 
 #include <termios.h>
-#include <unistd.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <stdarg.h>
-#include <string.h>
-#include <signal.h>
 #include <arpa/telnet.h>
-#include <sys/types.h>
-#include <sys/socket.h>
 #include <netinet/in.h>
 #include "busybox.h"
 
@@ -593,8 +585,9 @@ static void cookmode(void)
 
 int telnet_main(int argc, char** argv)
 {
+	char *host;
+	int port;
 	int len;
-	struct sockaddr_in s_in;
 #ifdef USE_POLL
 	struct pollfd ufds[2];
 #else
@@ -610,11 +603,10 @@ int telnet_main(int argc, char** argv)
 	ttype = getenv("TERM");
 #endif
 
-	memset(&G, 0, sizeof G);
+	/* memset(&G, 0, sizeof G); - already is */
 
 	if (tcgetattr(0, &G.termios_def) >= 0) {
 		G.do_termios = 1;
-
 		G.termios_raw = G.termios_def;
 		cfmakeraw(&G.termios_raw);
 	}
@@ -627,19 +619,18 @@ int telnet_main(int argc, char** argv)
 		autologin = getenv("USER");
 
 	if (optind < argc) {
-		bb_lookup_host(&s_in, argv[optind++]);
-		s_in.sin_port = bb_lookup_port((optind < argc) ? argv[optind++] :
+		host = argv[optind++];
+		port = bb_lookup_port((optind < argc) ? argv[optind++] :
 				"telnet", "tcp", 23);
 		if (optind < argc)
 			bb_show_usage();
 	} else
 		bb_show_usage();
 #else
-	bb_lookup_host(&s_in, argv[1]);
-	s_in.sin_port = bb_lookup_port((argc == 3) ? argv[2] : "telnet", "tcp", 23);
+	host = argv[1];
+	port = bb_lookup_port((argc > 2) ? argv[2] : "telnet", "tcp", 23);
 #endif
-
-	G.netfd = xconnect_tcp_v4(&s_in);
+	G.netfd = create_and_connect_stream_or_die(host, port);
 
 	setsockopt(G.netfd, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof one);
 
@@ -655,8 +646,7 @@ int telnet_main(int argc, char** argv)
 	maxfd = G.netfd + 1;
 #endif
 
-	while (1)
-	{
+	while (1) {
 #ifndef USE_POLL
 		fd_set rfds = readfds;
 
@@ -700,8 +690,7 @@ int telnet_main(int argc, char** argv)
 			{
 				len = read(G.netfd, G.buf, DATABUFSIZE);
 
-				if (len <= 0)
-				{
+				if (len <= 0) {
 					WriteCS(1, "Connection closed by foreign host.\r\n");
 					doexit(1);
 				}
diff --git a/networking/telnetd.c b/networking/telnetd.c
index 604f65c..a0ee2c3 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -414,7 +414,7 @@ telnetd_main(int argc, char **argv)
 	if (IS_INETD) {
 		sessions = make_new_session(0, 1);
 	} else {
-		master_fd = create_and_bind_socket_ip4or6(opt_bindaddr, portnbr);
+		master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr);
 		xlisten(master_fd, 1);
 		if (!(opt & OPT_FOREGROUND))
 			xdaemon(0, 0);