net: Split makesock(), part 1: Introduce lookup_address().

The lookup part is relatively independent and might be useful on its
own, so create lookup_address().

diff --git a/net.c b/net.c
index 70d3ec0f2d1ad297a8249acb3bd0f1a1a0815eb9..ccb9632de9a30f566450cea2e4a62e29bd0c530f 100644 (file)
--- a/net.c
+++ b/net.c
@@ -343,72 +343,91 @@ static void flowopt_cleanup(struct flowopts *fo)
        free(fo);
 }
 
-/**
- * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
+/*
+ * Resolve an IPv4/IPv6 address.
  *
  * \param l4type The layer-4 type (\p IPPROTO_xxx).
- * \param passive Whether this is a passive (1) or active (0) socket.
+ * \param passive Whether \p AI_PASSIVE should be included as hint.
  * \param host Remote or local hostname or IPv/6 address string.
- * \param port_number Decimal port number.
- * \param fo Socket options to be set before making the connection.
+ * \param port_number Used to set the port in each returned address structure.
+ * \param result addrinfo structures are returned here.
  *
- * This creates a ready-made IPv4/v6 socket structure after looking up the
- * necessary parameters. The interpretation of \a host depends on the value of
- * \a passive:
- *     - on a passive socket host is interpreted as an interface IPv4/6 address
- *       (can be left NULL);
- *     - on an active socket, \a host is the peer DNS name or IPv4/6 address
- *       to connect to;
- *     - \a port_number is in either case the numeric port number (not service
- *       string).
+ * The interpretation of \a host depends on the value of \a passive. On a
+ * passive socket host is interpreted as an interface IPv4/6 address (can be
+ * left NULL). On an active socket, \a host is the peer DNS name or IPv4/6
+ * address to connect to.
  *
- * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
- * sockets. The algorithm tries all possible address combinations until it
- * succeeds. If \a fo is supplied, options are set and cleanup is performed.
+ * \return Standard.
  *
- * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
- * matching connection could be set up (with details in the error log).
- *
- *  \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
+ * \sa getaddrinfo(3).
  */
-int makesock(unsigned l4type, bool passive,
-            const char *host, uint16_t port_number,
-            struct flowopts *fo)
+static int lookup_address(unsigned l4type, bool passive, const char *host,
+               int port_number, struct addrinfo **result)
 {
-       struct addrinfo *local = NULL, *src = NULL, *remote = NULL,
-               *dst = NULL, hints;
-       int             rc, on = 1, sockfd = -1,
-                       socktype = sock_type(l4type);
+       int ret;
        char port[6]; /* port number has at most 5 digits */
+       struct addrinfo *addr = NULL, hints;
 
-       sprintf(port, "%u", port_number);
+       *result = NULL;
+       sprintf(port, "%u", port_number & 0xffff);
        /* Set up address hint structure */
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
-       hints.ai_socktype = socktype;
-       /* 
+       hints.ai_socktype = sock_type(l4type);
+       /*
         * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
         * (and only then) pretend to be UDP.
         */
        if (l4type == IPPROTO_DCCP)
                hints.ai_socktype = SOCK_DGRAM;
-
        /* only use addresses available on the host */
        hints.ai_flags = AI_ADDRCONFIG;
-
        if (passive && host == NULL)
                hints.ai_flags |= AI_PASSIVE;
-
        /* Obtain local/remote address information */
-       if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
-               PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
-                               layer4_name(l4type),
-                               host? host : (passive? "[loopback]" : "[localhost]"),
-                               port, gai_strerror(rc));
-               rc = -E_ADDRESS_LOOKUP;
-               goto out;
+       ret = getaddrinfo(host, port, &hints, &addr);
+       if (ret != 0) {
+               PARA_ERROR_LOG("can not resolve %s address %s#%s: %s\n",
+                       layer4_name(l4type),
+                       host? host : (passive? "[loopback]" : "[localhost]"),
+                       port, gai_strerror(ret));
+               return -E_ADDRESS_LOOKUP;
        }
+       *result = addr;
+       return 1;
+}
 
+/**
+ * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
+ *
+ * \param l4type The layer-4 type (\p IPPROTO_xxx).
+ * \param passive Whether this is a passive or active socket.
+ * \param host Passed to \ref \a lookup_address().
+ * \param port_number Passed to \ref \a lookup_address().
+ * \param fo Socket options to be set before making the connection.
+ *
+ * This creates a ready-made IPv4/v6 socket structure after looking up the
+ * necessary parameters.
+ *
+ * bind(2) is called on passive sockets, and connect(2) on active sockets. The
+ * algorithm tries all possible address combinations until it succeeds. If \a
+ * fo is supplied, options are set and cleanup is performed.
+ *
+ * \return Standard.
+ *
+ *  \sa \ref lookup_address(), ipv6(7), getaddrinfo(3), bind(2), connect(2).
+ */
+int makesock(unsigned l4type, bool passive,
+            const char *host, uint16_t port_number,
+            struct flowopts *fo)
+{
+       struct addrinfo *local = NULL, *src = NULL, *remote = NULL, *dst = NULL;
+       int rc, on = 1, sockfd = -1;
+
+       rc = lookup_address(l4type, passive, host, port_number, passive?
+               &local : &remote);
+       if (rc < 0)
+               goto out;
        /* Iterate over all src/dst combination, exhausting dst first */
        for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
                if (src && dst && src->ai_family == AF_INET
@@ -416,7 +435,7 @@ int makesock(unsigned l4type, bool passive,
                        goto get_next_dst; /* v4 -> v6 is not possible */
 
                sockfd = socket(src ? src->ai_family : dst->ai_family,
-                       socktype, l4type);
+                       sock_type(l4type), l4type);
                if (sockfd < 0)
                        goto get_next_dst;
 
@@ -465,9 +484,9 @@ out:
        if (src == NULL && dst == NULL) {
                if (rc >= 0)
                        rc = -E_MAKESOCK;
-               PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
+               PARA_ERROR_LOG("can not create %s socket %s#%d.\n",
                        layer4_name(l4type), host? host : (passive?
-                       "[loopback]" : "[localhost]"), port);
+                       "[loopback]" : "[localhost]"), port_number);
                return rc;
        }
        return sockfd;