telnetd: if FEATURE_IPV6 is on, telnet will NOT work on IPv4

which is kind of stupid

1 files changed, 65 insertions, 21 deletions

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 549488507..d524ac891 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -37,10 +37,8 @@
 #define BUFSIZE 4000
 
 #if ENABLE_FEATURE_IPV6
-#define SOCKET_TYPE     AF_INET6
 typedef struct sockaddr_in6 sockaddr_type;
 #else
-#define SOCKET_TYPE     AF_INET
 typedef struct sockaddr_in sockaddr_type;
 #endif
 
@@ -357,31 +355,77 @@ free_session(struct tsession *ts)
 }
 
 static int
-create_socket(int port, const char *opt_bindaddr)
+dotted2sockaddr(const char *dotted, struct sockaddr* sp, int socklen)
+{
+        union {
+                struct in_addr a4;
+#if ENABLE_FEATURE_IPV6
+                struct in6_addr a6;
+#endif
+        } a;
+
+#if ENABLE_FEATURE_IPV6
+        if (socklen >= sizeof(struct sockaddr_in6)
+         && inet_pton(AF_INET6, dotted, &a) > 0
+        ) {
+                ((struct sockaddr_in6*)sp)->sin6_family = AF_INET6;
+                ((struct sockaddr_in6*)sp)->sin6_addr = a.a6;
+        } else
+#endif
+        if (socklen >= sizeof(struct sockaddr_in)
+         && inet_pton(AF_INET, dotted, &a) > 0
+        ) {
+                ((struct sockaddr_in*)sp)->sin_family = AF_INET;
+                ((struct sockaddr_in*)sp)->sin_addr = a.a4;
+        } else
+                return 1;
+
+        return 0; /* success */
+}
+
+static int
+xsocket_stream_ip4or6(sa_family_t *fp)
+{
+        int fd = socket(AF_INET6, SOCK_STREAM, 0);
+        if (fp) *fp = AF_INET6;
+        if (fd < 0) {
+                fd = xsocket(AF_INET, SOCK_STREAM, 0);
+                if (fp) *fp = AF_INET;
+        }
+        return fd;
+}
+
+static int
+create_socket(const char *hostaddr, int port)
 {
         static const int on = 1;
         int fd;
-        sockaddr_type sa;
-#if !ENABLE_FEATURE_IPV6
-        struct in_addr bind_addr = { .s_addr = 0x0 };
+        union {
+                struct sockaddr sa;
+                struct sockaddr_in sin;
+#if ENABLE_FEATURE_IPV6
+                struct sockaddr_in6 sin6;
+#endif
+        } sa;
 
-        /* TODO: generic string -> sockaddr converter */
-        if (opt_bindaddr && inet_aton(opt_bindaddr, &bind_addr) == 0)
+        memset(&sa, 0, sizeof(sa));
+        if (hostaddr && dotted2sockaddr(hostaddr, &sa.sa, sizeof(sa)))
                 bb_show_usage();
-#endif
-        fd = xsocket(SOCKET_TYPE, SOCK_STREAM, 0);
+
+        if (!sa.sa.sa_family)
+                fd = xsocket_stream_ip4or6(&sa.sa.sa_family);
+        else /* user specified -b ADDR dictates family */
+                fd = xsocket(sa.sa.sa_family, SOCK_STREAM, 0);
         setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
-        memset((void *)&sa, 0, sizeof(sa));
+
 #if ENABLE_FEATURE_IPV6
-        sa.sin6_family = AF_INET6;
-        sa.sin6_port = htons(port);
-        /* sa.sin6_addr = bind_addr6; */
-#else
-        sa.sin_family = AF_INET;
-        sa.sin_port = htons(port);
-        sa.sin_addr = bind_addr;
+        if (sa.sa.sa_family == AF_INET6)
+                sa.sin6.sin6_port = htons(port);
 #endif
-        xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
+        if (sa.sa.sa_family == AF_INET)
+                sa.sin.sin_port = htons(port);
+
+        xbind(fd, &sa.sa, sizeof(sa));
         xlisten(fd, 1);
         return fd;
 }
@@ -390,7 +434,7 @@ create_socket(int port, const char *opt_bindaddr)
 
 /* Never actually called */
 void free_session(struct tsession *ts);
-int create_socket(int port, const char *opt_bindaddr);
+int create_socket(const char *hostaddr, int port);
 
 #endif
 
@@ -447,7 +491,7 @@ telnetd_main(int argc, char **argv)
         if (IS_INETD) {
                 sessions = make_new_session(0, 1);
         } else {
-                master_fd = create_socket(portnbr, opt_bindaddr);
+                master_fd = create_socket(opt_bindaddr, portnbr);
                 if (!(opt & OPT_FOREGROUND))
                         xdaemon(0, 0);
         }