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).

1 files changed, 151 insertions, 83 deletions

diff --git a/libbb/xconnect.c b/libbb/xconnect.c
index bc0691531..93c3cd5c6 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;
 }