ifconfig-ipv6(-push): allow using hostnames

Similarly to ifconfig(-push), its IPv6 counterpart is now able to
accept hostnames as well instead of IP addresses in numeric form.

Basically this means that the user is now allowed to specify
something like this:

ifconfig-ipv6-push my.hostname.cx/64

This is exactly the same behaviour that we already have with
ifconfig(-push).

The generic code introduced in this patch will be later used to
implement the /bits parsing support for IPv4 addresses.

Trac: #808
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Selva Nair <selva.nair@gmail.com>
Message-Id: <20171203041426.25316-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15969.html
Signed-off-by: David Sommerseth <davids@openvpn.net>

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 0421185f98352a7026cb1d356bcd2b9d2b948340..5c669e9119b5ff2e6ac7db7b318f45b5edcc9815 100644 (file)
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -1023,67 +1023,6 @@ get_ip_addr(const char *ip_string, int msglevel, bool *error)
     return ret;
 }
 
-/* helper: parse a text string containing an IPv6 address + netbits
- * in "standard format" (2001:dba::/32)
- * "/nn" is optional, default to /64 if missing
- *
- * return true if parsing succeeded, modify *network and *netbits
- */
-bool
-get_ipv6_addr( const char *prefix_str, struct in6_addr *network,
-               unsigned int *netbits, int msglevel)
-{
-    char *sep, *endp;
-    int bits;
-    struct in6_addr t_network;
-
-    sep = strchr( prefix_str, '/' );
-    if (sep == NULL)
-    {
-        bits = 64;
-    }
-    else
-    {
-        bits = strtol( sep+1, &endp, 10 );
-        if (*endp != '\0' || bits < 0 || bits > 128)
-        {
-            msg(msglevel, "IPv6 prefix '%s': invalid '/bits' spec", prefix_str);
-            return false;
-        }
-    }
-
-    /* temporary replace '/' in caller-provided string with '\0', otherwise
-     * inet_pton() will refuse prefix string
-     * (alternative would be to strncpy() the prefix to temporary buffer)
-     */
-
-    if (sep != NULL)
-    {
-        *sep = '\0';
-    }
-
-    if (inet_pton( AF_INET6, prefix_str, &t_network ) != 1)
-    {
-        msg(msglevel, "IPv6 prefix '%s': invalid IPv6 address", prefix_str);
-        return false;
-    }
-
-    if (sep != NULL)
-    {
-        *sep = '/';
-    }
-
-    if (netbits != NULL)
-    {
-        *netbits = bits;
-    }
-    if (network != NULL)
-    {
-        *network = t_network;
-    }
-    return true;                /* parsing OK, values set */
-}
-
 /**
  * Returns newly allocated string containing address part without "/nn".
  *

diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index 33b1e45ad66c85908c8700e6f0617535d74716bd..8f49a96fb265b544527f60048a35372715ae4d61 100644 (file)
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -819,8 +819,4 @@ void options_string_import(struct options *options,
                            unsigned int *option_types_found,
                            struct env_set *es);
 
-bool get_ipv6_addr( const char *prefix_str, struct in6_addr *network,
-                    unsigned int *netbits, int msglevel );
-
-
 #endif /* ifndef OPTIONS_H */

diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index 0eda25ccc2d3757f5a0d15819b8dd7c8f9fb53a5..3f2b97e492b4856c6c6717f747d2aee082722d82 100644 (file)
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -75,12 +75,116 @@ sf2gaf(const unsigned int getaddr_flags,
 /*
  * Functions related to the translation of DNS names to IP addresses.
  */
+static int
+get_addr_generic(sa_family_t af, unsigned int flags, const char *hostname,
+                 void *network, unsigned int *netbits,
+                 int resolve_retry_seconds, volatile int *signal_received,
+                 int msglevel)
+{
+    char *endp, *sep, *var_host = NULL;
+    struct addrinfo *ai = NULL;
+    unsigned long bits;
+    uint8_t max_bits;
+    int ret = -1;
+
+    if (!hostname)
+    {
+        msg(M_NONFATAL, "Can't resolve null hostname!");
+        goto out;
+    }
+
+    /* assign family specific default values */
+    switch (af)
+    {
+        case AF_INET:
+            bits = 0;
+            max_bits = sizeof(in_addr_t) * 8;
+            break;
+        case AF_INET6:
+            bits = 64;
+            max_bits = sizeof(struct in6_addr) * 8;
+            break;
+        default:
+            msg(M_WARN,
+                "Unsupported AF family passed to getaddrinfo for %s (%d)",
+                hostname, af);
+            goto out;
+    }
+
+    /* we need to modify the hostname received as input, but we don't want to
+     * touch it directly as it might be a constant string.
+     *
+     * Therefore, we clone the string here and free it at the end of the
+     * function */
+    var_host = strdup(hostname);
+    if (!var_host)
+    {
+        msg(M_NONFATAL | M_ERRNO,
+            "Can't allocate hostname buffer for getaddrinfo");
+        goto out;
+    }
+
+    /* check if this hostname has a /bits suffix */
+    sep = strchr(var_host , '/');
+    if (sep)
+    {
+        bits = strtoul(sep + 1, &endp, 10);
+        if ((*endp != '\0') || (bits > max_bits))
+        {
+            msg(msglevel, "IP prefix '%s': invalid '/bits' spec (%s)", hostname,
+                sep + 1);
+            goto out;
+        }
+        *sep = '\0';
+    }
+
+    ret = openvpn_getaddrinfo(flags & ~GETADDR_HOST_ORDER, var_host, NULL,
+                              resolve_retry_seconds, signal_received, af, &ai);
+    if ((ret == 0) && network)
+    {
+        struct in6_addr *ip6;
+        in_addr_t *ip4;
+
+        switch (af)
+        {
+            case AF_INET:
+                ip4 = network;
+                *ip4 = ((struct sockaddr_in *)ai->ai_addr)->sin_addr.s_addr;
+
+                if (flags & GETADDR_HOST_ORDER)
+                {
+                    *ip4 = ntohl(*ip4);
+                }
+                break;
+            case AF_INET6:
+                ip6 = network;
+                *ip6 = ((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
+                break;
+            default:
+                /* can't get here because 'af' was previously checked */
+                msg(M_WARN,
+                    "Unsupported AF family for %s (%d)", var_host, af);
+                goto out;
+        }
+    }
+
+    if (netbits)
+    {
+        *netbits = bits;
+    }
+
+    /* restore '/' separator, if any */
+    if (sep)
+    {
+        *sep = '/';
+    }
+out:
+    freeaddrinfo(ai);
+    free(var_host);
+
+    return ret;
+}
 
-/*
- * Translate IP addr or hostname to in_addr_t.
- * If resolve error, try again for
- * resolve_retry_seconds seconds.
- */
 in_addr_t
 getaddr(unsigned int flags,
         const char *hostname,
@@ -88,20 +192,19 @@ getaddr(unsigned int flags,
         bool *succeeded,
         volatile int *signal_received)
 {
-    struct addrinfo *ai;
+    in_addr_t addr;
     int status;
-    status = openvpn_getaddrinfo(flags & ~GETADDR_HOST_ORDER, hostname, NULL,
-                                 resolve_retry_seconds, signal_received, AF_INET, &ai);
+
+    status = get_addr_generic(AF_INET, flags, hostname, &addr, NULL,
+                              resolve_retry_seconds, signal_received,
+                              M_WARN);
     if (status==0)
     {
-        struct in_addr ia;
         if (succeeded)
         {
             *succeeded = true;
         }
-        ia = ((struct sockaddr_in *)ai->ai_addr)->sin_addr;
-        freeaddrinfo(ai);
-        return (flags & GETADDR_HOST_ORDER) ? ntohl(ia.s_addr) : ia.s_addr;
+        return addr;
     }
     else
     {
@@ -113,6 +216,19 @@ getaddr(unsigned int flags,
     }
 }
 
+bool
+get_ipv6_addr(const char *hostname, struct in6_addr *network,
+              unsigned int *netbits, int msglevel)
+{
+    if (get_addr_generic(AF_INET6, GETADDR_RESOLVE, hostname, network, netbits,
+                         0, NULL, msglevel) < 0)
+    {
+        return false;
+    }
+
+    return true;                /* parsing OK, values set */
+}
+
 static inline bool
 streqnull(const char *a, const char *b)
 {

diff --git a/src/openvpn/socket.h b/src/openvpn/socket.h
index b445821ce82a265d565bff579c7a1f327fea1485..0f22d47968e89dc2c0b1c91d05eb2c40f5ee62e3 100644 (file)
--- a/src/openvpn/socket.h
+++ b/src/openvpn/socket.h
@@ -532,12 +532,24 @@ bool unix_socket_get_peer_uid_gid(const socket_descriptor_t sd, int *uid, int *g
 
 #define GETADDR_CACHE_MASK              (GETADDR_DATAGRAM|GETADDR_PASSIVE)
 
+/**
+ * Translate an IPv4 addr or hostname from string form to in_addr_t
+ *
+ * In case of resolve error, it will try again for
+ * resolve_retry_seconds seconds.
+ */
 in_addr_t getaddr(unsigned int flags,
                   const char *hostname,
                   int resolve_retry_seconds,
                   bool *succeeded,
                   volatile int *signal_received);
 
+/**
+ * Translate an IPv6 addr or hostname from string form to in6_addr
+ */
+bool get_ipv6_addr(const char *hostname, struct in6_addr *network,
+                   unsigned int *netbits, int msglevel);
+
 int openvpn_getaddrinfo(unsigned int flags,
                         const char *hostname,
                         const char *servname,