shim-udp: resolve dst_name using DNS

This commits adds the gethostbyname call to resolve the dst_name for a
flow allocation using DNS. The DNS server should be specified using
the method mandated by the system (e.g. added to /etc/resolv.conf).

3 files changed, 37 insertions, 20 deletions

diff --git a/src/ipcpd/shim-udp/CMakeLists.txt b/src/ipcpd/shim-udp/CMakeLists.txt
index 27907880..f730fa3a 100644
--- a/src/ipcpd/shim-udp/CMakeLists.txt
+++ b/src/ipcpd/shim-udp/CMakeLists.txt
@@ -10,6 +10,21 @@ include_directories(${CURRENT_BINARY_PARENT_DIR})
 include_directories(${CMAKE_SOURCE_DIR}/include)
 include_directories(${CMAKE_BINARY_DIR}/include)
 
+# Find library needed for gethostbyname.
+include(CheckFunctionExists)
+CHECK_FUNCTION_EXISTS("gethostbyname" CMAKE_HAVE_GETHOSTBYNAME)
+IF(NOT CMAKE_HAVE_GETHOSTBYNAME)
+    CHECK_LIBRARY_EXISTS("nsl" "gethostbyname" "" CMAKE_LIB_NSL_HAS_GETHOSTBYNAME)
+    IF (CMAKE_LIB_NSL_HAS_GETHOSTBYNAME)
+        SET (X11_X_EXTRA_LIBS ${X11_X_EXTRA_LIBS} -lnsl)
+    ELSE (CMAKE_LIB_NSL_HAS_GETHOSTBYNAME)
+        CHECK_LIBRARY_EXISTS("bsd" "gethostbyname" "" CMAKE_LIB_BSD_HAS_GETHOSTBYNAME)
+        IF (CMAKE_LIB_BSD_HAS_GETHOSTBYNAME)
+             SET (X11_X_EXTRA_LIBS ${X11_X_EXTRA_LIBS} -lbsd)
+        ENDIF (CMAKE_LIB_BSD_HAS_GETHOSTBYNAME)
+    ENDIF (CMAKE_LIB_NSL_HAS_GETHOSTBYNAME)
+ENDIF(NOT CMAKE_HAVE_GETHOSTBYNAME)
+
 SET(IPCP_SHIM_UDP_TARGET ipcpd-shim-udp CACHE STRING "IPCP_SHIM_UDP_TARGET")
 
 set(SHIM_UDP_SOURCES
diff --git a/src/ipcpd/shim-udp/main.c b/src/ipcpd/shim-udp/main.c
index 785f2344..029df111 100644
--- a/src/ipcpd/shim-udp/main.c
+++ b/src/ipcpd/shim-udp/main.c
@@ -21,7 +21,6 @@
  */
 
 #include <ouroboros/config.h>
-
 #include "ipcp.h"
 #include "flow.h"
 #include <ouroboros/shm_du_map.h>
@@ -310,7 +309,7 @@ int ipcp_udp_bootstrap(struct dif_config * conf)
                           dnsstr,
                           INET_ADDRSTRLEN);
         else
-                strcpy(dnsstr, "not set");
+                strcpy(dnsstr, "not set.\n");
 
         shim_data(_ipcp)->ip_addr  = conf->ip_addr;
         shim_data(_ipcp)->dns_addr = conf->dns_addr;
@@ -381,7 +380,7 @@ int ipcp_udp_name_unreg(char * name)
 }
 
 int ipcp_udp_flow_alloc(uint32_t          port_id,
-                        char *            dst_ap_name,
+                        char *            dst_name,
                         char *            src_ap_name,
                         char *            src_ae_name,
                         struct qos_spec * qos)
@@ -390,16 +389,18 @@ int ipcp_udp_flow_alloc(uint32_t          port_id,
         struct sockaddr_in l_saddr;
         struct sockaddr_in r_saddr;
 
+        struct hostent * h;
+
         irm_msg_t   msg = IRM_MSG__INIT;
         irm_msg_t * ret_msg = NULL;
 
-        if (dst_ap_name == NULL || src_ap_name == NULL || src_ae_name == NULL)
+        if (dst_name == NULL || src_ap_name == NULL || src_ae_name == NULL)
                 return -1;
 
         LOG_DBG("Received flow allocation request from %s to %s.",
-                src_ap_name, dst_ap_name);
+                src_ap_name, dst_name);
 
-        if (strlen(dst_ap_name) > 255
+        if (strlen(dst_name) > 255
             || strlen(src_ap_name) > 255
             || strlen(src_ae_name) > 255) {
                 LOG_ERR("Name too long for this shim.");
@@ -436,20 +437,21 @@ int ipcp_udp_flow_alloc(uint32_t          port_id,
                 return -1;
         }
 
-        /* FIXME: use calls to specify DDNS server */
-
-#define IP_ADDR 0x7f000001; /* localhost */
+        h = gethostbyname(dst_name);
+        if (h == NULL) {
+                close(flow->fd);
+                free(flow);
+                return -1;
+        }
 
-        LOG_MISSING;
 
         memset((char *) &r_saddr, 0, sizeof r_saddr);
         r_saddr.sin_family      = AF_INET;
-        /* FIXME: pull in correct IP address */
-        r_saddr.sin_addr.s_addr = IP_ADDR; /* FIXME */
+        r_saddr.sin_addr.s_addr = (uint32_t) *(h->h_addr_list[0]);
         r_saddr.sin_port        = LISTEN_PORT;
 
         /* at least try to get the packet on the wire */
-        while (sendto(flow->fd, dst_ap_name, strlen(dst_ap_name), 0,
+        while (sendto(flow->fd, dst_name, strlen(dst_name), 0,
                       (struct sockaddr *) &r_saddr, sizeof r_saddr) < 0)
 
         flow->flow.port_id = port_id;
diff --git a/src/ipcpd/shim-udp/tests/shim_udp_test.c b/src/ipcpd/shim-udp/tests/shim_udp_test.c
index 4e0c2dd6..d2b9c642 100644
--- a/src/ipcpd/shim-udp/tests/shim_udp_test.c
+++ b/src/ipcpd/shim-udp/tests/shim_udp_test.c
@@ -42,10 +42,10 @@ int shim_udp_test(int argc, char ** argv)
         int i = 0;
 
         char bogus[15];
-        memset (&bogus, 0, 15);
+        memset(&bogus, 0, 15);
 
         struct dif_config conf;
-        memset (&conf, 0, sizeof conf);
+        memset(&conf, 0, sizeof conf);
         conf.dif_name = strdup("test-dif");
         conf.type = IPCP_SHIM_UDP;
         conf.ip_addr = 0;
@@ -63,11 +63,11 @@ int shim_udp_test(int argc, char ** argv)
                 exit(1);
         }
 
-        if (ipcp_udp_bootstrap (&conf)) {
+        if (ipcp_udp_bootstrap(&conf)) {
                 LOG_ERR("Could not bootstrap.");
         }
 
-        if(ipcp_udp_name_reg("bogus name")) {
+        if (ipcp_udp_name_reg("bogus name")) {
                 LOG_ERR("Failed to register application.");
                 shm_du_map_close(dum);
                 exit(1);
@@ -80,8 +80,8 @@ int shim_udp_test(int argc, char ** argv)
         }
 
         for (i = 0; i  < 1000; ++i) {
-                sprintf (bogus, "bogus name %4d", i);
-                if(ipcp_udp_name_reg(bogus)) {
+                sprintf(bogus, "bogus name %4d", i);
+                if (ipcp_udp_name_reg(bogus)) {
                          LOG_ERR("Failed to register application %s.", bogus);
                          shm_du_map_close(dum);
                          exit(1);
@@ -89,7 +89,7 @@ int shim_udp_test(int argc, char ** argv)
         }
 
         for (i = 0; i  < 1000; ++i) {
-                sprintf (bogus, "bogus name %4d", i);
+                sprintf(bogus, "bogus name %4d", i);
                 if(ipcp_udp_name_unreg(bogus)) {
                          LOG_ERR("Failed to unregister application %s.", bogus);
                          shm_du_map_close(dum);