Add proper BSD interface detection code. Fixes a long-standing

discussion on the users list (see
http://www.open-mpi.org/community/lists/users/2009/12/11526.php). 

Many thanks to Kevin Buckley who did most of the coding work, and to
Aleksej Saushev for his extreme patience in waiting for me to review
and commit this stuff.

This commit was SVN r22640.

opal/util/if.c

@@ -38,6 +38,9 @@
 #endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
+#if defined(__DragonFly__)
+#define IN_LINKLOCAL(i)        (((u_int32_t)(i) & 0xffff0000) == 0xa9fe0000)
+#endif
 #endif
 #ifdef HAVE_ARPA_INET_H
 #include <arpa/inet.h>
@@ -164,6 +167,126 @@ static int opal_ifinit(void)
                                 false, false, (int)false, &sd);
     do_not_resolve = OPAL_INT_TO_BOOL(sd);
 
+#if defined(__NetBSD__) || defined(__FreeBSD__) || \
+    defined(__OpenBSD__) || defined(__DragonFly__)
+    /* configure using getifaddrs(3) */
+    {
+        OBJ_CONSTRUCT(&opal_if_list, opal_list_t);
+
+        struct ifaddrs **ifadd_list;
+        struct ifaddrs *cur_ifaddrs;
+        struct sockaddr_in* sin_addr;
+
+        /* 
+         * the manpage claims that getifaddrs() allocates the memory,
+         * and freeifaddrs() is later used to release the allocated memory.
+         * however, without this malloc the call to getifaddrs() segfaults
+         */
+        ifadd_list = (struct ifaddrs **) malloc(sizeof(struct ifaddrs*));
+
+        /* create the linked list of ifaddrs structs */
+        if(getifaddrs(ifadd_list) < 0) {
+            opal_output(0, "opal_ifinit: getifaddrs() failed with error=%d\n",
+                    errno);
+            return OPAL_ERROR;
+        }
+
+        for(cur_ifaddrs = *ifadd_list; NULL != cur_ifaddrs; 
+                cur_ifaddrs = cur_ifaddrs->ifa_next) {
+
+            opal_if_t intf;
+            opal_if_t *intf_ptr;
+            struct in_addr a4;
+
+            /* skip non- af_inet interface addresses */
+            if(AF_INET != cur_ifaddrs->ifa_addr->sa_family) {
+		continue;
+	    }
+
+            /* skip interface if it is down (IFF_UP not set) */
+            if(0 == (cur_ifaddrs->ifa_flags & IFF_UP)) {
+                continue;
+            }
+
+            /* skip interface if it is a loopback device (IFF_LOOPBACK set) */
+            /* or if it is a point-to-point interface */
+            /* TODO: do we really skip p2p? */
+            if(0 != (cur_ifaddrs->ifa_flags & IFF_LOOPBACK)
+                    || 0!= (cur_ifaddrs->ifa_flags & IFF_POINTOPOINT)) {
+                continue;
+            }
+
+            sin_addr = (struct sockaddr_in *) cur_ifaddrs->ifa_addr;
+
+	    /* Do we really need to skip link-local addresses? */
+#if 0
+            /* skip link local address: */
+            if(IN_LINKLOCAL (htonl(((struct sockaddr_in*)cur_ifaddrs->ifa_addr)->sin_addr.s_addr))) {
+#if 0
+                opal_output(0, "opal_ifinit: skipping link-local ip address on interface %s.\n",
+                        cur_ifaddrs->ifa_name);
+#endif
+                continue;
+            }
+#endif
+
+            memset(&intf, 0, sizeof(intf));
+            OBJ_CONSTRUCT(&intf, opal_list_item_t);
+#if 0 
+            char *addr_name = (char *) malloc(48*sizeof(char));
+            inet_ntop(AF_INET, &sin_addr->sin_addr, addr_name, 48*sizeof(char));
+            opal_output(0, "inet capable interface %s discovered, address %s.\n", 
+                    cur_ifaddrs->ifa_name, addr_name);
+            free(addr_name);
+#endif
+
+            /* fill values into the opal_if_t */
+            memcpy(&a4, &(sin_addr->sin_addr), sizeof(struct in_addr));
+            
+            strncpy(intf.if_name, cur_ifaddrs->ifa_name, IF_NAMESIZE);
+            intf.if_index = opal_list_get_size(&opal_if_list) + 1;
+            ((struct sockaddr_in*) &intf.if_addr)->sin_addr = a4;
+            ((struct sockaddr_in*) &intf.if_addr)->sin_family = AF_INET;
+            ((struct sockaddr_in*) &intf.if_addr)->sin_len =  cur_ifaddrs->ifa_addr->sa_len;
+
+            /* since every scope != 0 is ignored, we just set the scope to 0 */
+            /* There's no scope_id in the non-ipv6 stuff 
+	    ((struct sockaddr_in6*) &intf.if_addr)->sin6_scope_id = 0; 
+	    */
+
+            /*
+             * hardcoded netmask, adrian says that's ok
+             */
+	    /* Non-NetBSD uses intf.if_mask = prefix(((struct sockaddr_in*) &ifr->ifr_addr)->sin_addr.s_addr); */
+            /* intf.if_mask = 64; */
+	    intf.if_mask = prefix( sin_addr->sin_addr.s_addr);
+            intf.if_flags = cur_ifaddrs->ifa_flags;
+
+            /*
+             * FIXME: figure out how to gain access to the kernel index
+             * (or create our own), getifaddrs() does not contain such
+             * data
+             */
+
+            intf.if_kernel_index = (uint16_t) if_nametoindex(cur_ifaddrs->ifa_name);
+
+            intf_ptr = (opal_if_t*) calloc(1, sizeof(opal_if_t));
+            if(NULL == intf_ptr) {
+                opal_output(0, "opal_ifinit: unable to allocate %lu bytes\n",
+                            sizeof(opal_if_t));
+                OBJ_DESTRUCT(&intf);
+                return OPAL_ERR_OUT_OF_RESOURCE;
+            }
+            memcpy(intf_ptr, &intf, sizeof(intf));
+
+	    /* opal_list_append(&opal_if_list, &intf_ptr->super); */
+            opal_list_append(&opal_if_list, (opal_list_item_t*) intf_ptr);
+
+            OBJ_DESTRUCT(&intf);
+        }   /*  of for loop over ifaddrs list */
+
+    }
+#else
     /* create the internet socket to test off */
 /*
    Change AF_INET to AF_UNSPEC (or AF_INET6) and everything will fail.
@@ -356,6 +479,10 @@ static int opal_ifinit(void)
     }
     free(ifconf.ifc_req);
     close(sd);
+
+#endif /* anything other than {Net,Open,Free}BSD and DragonFly */
+
+
 #if OPAL_WANT_IPV6
 #ifdef __linux__ /* Linux does not have SIOCGL*, so parse
                      /proc/net/if_inet6 instead */