Merged in sandervrijders/ouroboros/be (pull request #72)

ipcpd: Allow disabling of DNS

3 files changed, 235 insertions, 54 deletions

diff --git a/src/ipcpd/shim-udp/CMakeLists.txt b/src/ipcpd/shim-udp/CMakeLists.txt
index c71fa00b..e10a8ca6 100644
--- a/src/ipcpd/shim-udp/CMakeLists.txt
+++ b/src/ipcpd/shim-udp/CMakeLists.txt
@@ -1,5 +1,7 @@
-get_filename_component(CURRENT_SOURCE_PARENT_DIR ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
-get_filename_component(CURRENT_BINARY_PARENT_DIR ${CMAKE_CURRENT_BINARY_DIR} DIRECTORY)
+get_filename_component(CURRENT_SOURCE_PARENT_DIR
+  ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
+get_filename_component(CURRENT_BINARY_PARENT_DIR
+  ${CMAKE_CURRENT_BINARY_DIR} DIRECTORY)
 
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
@@ -18,33 +20,59 @@ IF(NOT CMAKE_HAVE_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)
+    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)
 
-# Find the nsupdate executable
-find_program(NSUPDATE_EXECUTABLE
-  NAMES nsupdate
-  DOC "The nsupdate tool that enables DDNS")
+# Enable DNS by default
+if (NOT DISABLE_DNS MATCHES True)
+  # Find the nsupdate executable
+  find_program(NSUPDATE_EXECUTABLE
+    NAMES nsupdate
+    DOC "The nsupdate tool that enables DDNS")
 
-if (${NSUPDATE_EXECUTABLE} STREQUAL "NSUPDATE_EXECUTABLE-NOTFOUND")
-  message(FATAL_ERROR "Could not find nsupdate, which is needed for DDNS")
-else()
-  message("-- Found nsupdate: ${NSUPDATE_EXECUTABLE}")
+  if (${NSUPDATE_EXECUTABLE} STREQUAL "NSUPDATE_EXECUTABLE-NOTFOUND")
+    message(FATAL_ERROR "Could not find nsupdate, which is needed for DDNS")
+  else()
+    message("-- Found nsupdate: ${NSUPDATE_EXECUTABLE}")
+  endif()
+
+  # Find the nslookup executable
+  find_program(NSLOOKUP_EXECUTABLE
+    NAMES nslookup
+    DOC "The nslookup tool that resolves DNS names")
+
+  if (${NSLOOKUP_EXECUTABLE} STREQUAL "NSLOOKUP_EXECUTABLE-NOTFOUND")
+    message(FATAL_ERROR
+      "Could not find nslookup, which is needed for DNS resolution")
+  else()
+    message("-- Found nslookup: ${NSLOOKUP_EXECUTABLE}")
+  endif()
 endif()
 
+configure_file(
+  "${CMAKE_CURRENT_SOURCE_DIR}/shim_udp_config.h.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/shim_udp_config.h")
+
 SET(IPCP_SHIM_UDP_TARGET ipcpd-shim-udp CACHE STRING "IPCP_SHIM_UDP_TARGET")
 
 set(SHIM_UDP_SOURCES
   # Add source files here
   ${CMAKE_CURRENT_SOURCE_DIR}/main.c)
 
-add_executable (ipcpd-shim-udp ${SHIM_UDP_SOURCES} ${IPCP_SOURCES})
+add_executable (ipcpd-shim-udp ${SHIM_UDP_SOURCES} ${IPCP_SOURCES}
+  "${CMAKE_CURRENT_BINARY_DIR}/shim_udp_config.h")
 target_link_libraries (ipcpd-shim-udp LINK_PUBLIC ouroboros)
 
+# Enable DNS by default
+if (NOT DISABLE_DNS MATCHES True)
+  MACRO_ADD_COMPILE_FLAGS(ipcpd-shim-udp -DCONFIG_OUROBOROS_ENABLE_DNS)
+endif()
+
 include(MacroAddCompileFlags)
 if (CMAKE_BUILD_TYPE MATCHES Debug)
   MACRO_ADD_COMPILE_FLAGS(ipcpd-shim-udp -DCONFIG_OUROBOROS_DEBUG)
diff --git a/src/ipcpd/shim-udp/main.c b/src/ipcpd/shim-udp/main.c
index e213f019..bb5c233f 100644
--- a/src/ipcpd/shim-udp/main.c
+++ b/src/ipcpd/shim-udp/main.c
@@ -23,6 +23,7 @@
 #include <ouroboros/config.h>
 #include "ipcp.h"
 #include "flow.h"
+#include "shim_udp_config.h"
 #include <ouroboros/shm_du_map.h>
 #include <ouroboros/shm_ap_rbuff.h>
 #include <ouroboros/list.h>
@@ -31,6 +32,7 @@
 #include <ouroboros/dif_config.h>
 #include <ouroboros/sockets.h>
 #include <ouroboros/bitmap.h>
+#include <ouroboros/dev.h>
 
 #define OUROBOROS_PREFIX "ipcpd/shim-udp"
 
@@ -74,19 +76,6 @@ struct ipcp * _ipcp;
  * the info
  */
 
-#define UNKNOWN_AP "__UNKNOWN_AP__"
-#define UNKNOWN_AE "__UNKNOWN_AE__"
-
-#define AP_MAX_FLOWS 256
-
-#ifndef DU_BUFF_HEADSPACE
-  #define DU_BUFF_HEADSPACE 128
-#endif
-
-#ifndef DU_BUFF_TAILSPACE
-  #define DU_BUFF_TAILSPACE 0
-#endif
-
 /* the shim needs access to these internals */
 struct shim_ap_data {
         instance_name_t *     api;
@@ -332,8 +321,11 @@ static void * ipcp_udp_listener()
                 }
 
                 /* echo back the packet */
-                while(send(fd, buf, strlen(buf), 0) < 0)
-                        ;
+                if (send(fd, buf, strlen(buf), 0) < 0) {
+                        LOG_ERR("Failed to echo back the packet.");
+                        close(fd);
+                        continue;
+                }
 
                 /* reply to IRM */
 
@@ -408,17 +400,27 @@ int ipcp_udp_bootstrap(struct dif_config * conf)
                 return -1;
         }
 
-        inet_ntop(AF_INET,
-                  &conf->ip_addr,
-                  ipstr,
-                  INET_ADDRSTRLEN);
+        if (inet_ntop(AF_INET,
+                      &conf->ip_addr,
+                      ipstr,
+                      INET_ADDRSTRLEN) == NULL) {
+                LOG_ERR("Failed to convert IP address");
+                return -1;
+        }
 
-        if (conf->dns_addr != 0)
-                inet_ntop(AF_INET,
-                          &conf->dns_addr,
-                          dnsstr,
-                          INET_ADDRSTRLEN);
-        else
+        if (conf->dns_addr != 0) {
+                if (inet_ntop(AF_INET,
+                              &conf->dns_addr,
+                              dnsstr,
+                              INET_ADDRSTRLEN) == NULL) {
+                        LOG_ERR("Failed to convert DNS address");
+                        return -1;
+                }
+#ifndef CONFIG_OUROBOROS_ENABLE_DNS
+                LOG_WARN("DNS address ignored since shim-udp was "
+                         "compiled without DNS support.");
+#endif
+        } else
                 strcpy(dnsstr, "not set");
 
         shim_data(_ipcp)->ip_addr  = conf->ip_addr;
@@ -480,7 +482,9 @@ int ipcp_udp_bootstrap(struct dif_config * conf)
         return 0;
 }
 
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
 /* FIXME: Dependency on nsupdate to be removed in the end */
+/* NOTE: Disgusted with this crap */
 static int ddns_send(char * cmd)
 {
         pid_t pid = 0;
@@ -509,7 +513,7 @@ static int ddns_send(char * cmd)
         close(pipe_fd[0]);
 
         if (write(pipe_fd[1], cmd, strlen(cmd)) == -1) {
-                LOG_ERR("Failed to register with DNS server.");
+                LOG_ERR("Failed to communicate with nsupdate.");
                 close(pipe_fd[1]);
                 return -1;
         }
@@ -525,14 +529,94 @@ static int ddns_send(char * cmd)
         return 0;
 }
 
+
+static uint32_t ddns_resolve(char * name, uint32_t dns_addr)
+{
+        pid_t pid = 0;
+        int wstatus;
+        int pipe_fd[2];
+        char dnsstr[INET_ADDRSTRLEN];
+        char buf[SHIM_UDP_BUF_SIZE];
+        ssize_t count = 0;
+        char * substr;
+        char * substr2;
+        char * addr_str = "Address:";
+        uint32_t ip_addr = 0;
+
+        if (inet_ntop(AF_INET, &dns_addr, dnsstr, INET_ADDRSTRLEN) == NULL) {
+                return 0;
+        }
+
+
+        if (pipe(pipe_fd)) {
+                LOG_ERR("Failed to create pipe.");
+                return 0;
+        }
+
+        pid = fork();
+        if (pid == -1) {
+                LOG_ERR("Failed to fork.");
+                return 0;
+        }
+
+        if (pid == 0) {
+                char * argv[] = {NSLOOKUP_EXEC, name, dnsstr, 0};
+                char * envp[] = {0};
+
+                close(pipe_fd[0]);
+                dup2(pipe_fd[1], 1);
+                execve(argv[0], &argv[0], envp);
+        }
+
+        close(pipe_fd[1]);
+
+        count = read(pipe_fd[0], buf, SHIM_UDP_BUF_SIZE);
+        if (count <= 0) {
+                LOG_ERR("Failed to communicate with nslookup.");
+                close(pipe_fd[0]);
+                return 0;
+        }
+
+        close(pipe_fd[0]);
+
+        waitpid(pid, &wstatus, 0);
+        if (WIFEXITED(wstatus) == true &&
+            WEXITSTATUS(wstatus) == 0)
+                LOG_DBGF("Succesfully communicated with nslookup.");
+        else
+                LOG_ERR("Failed to resolve DNS address.");
+
+        buf[count] = '\0';
+        substr = strtok(buf, "\n");
+        while (substr != NULL) {
+                substr2 = substr;
+                substr = strtok(NULL, "\n");
+        }
+
+        if (strstr(substr2, addr_str) == NULL) {
+                LOG_ERR("Failed to resolve DNS address.");
+                return 0;
+        }
+
+        if (inet_pton(AF_INET, substr2 + strlen(addr_str) + 1, &ip_addr) != 1) {
+                LOG_ERR("Failed to resolve DNS address.");
+                return 0;
+        }
+
+        return ip_addr;
+}
+#endif
+
 int ipcp_udp_name_reg(char * name)
 {
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
         char ipstr[INET_ADDRSTRLEN];
         char dnsstr[INET_ADDRSTRLEN];
         /* max DNS name length + max IP length + command length */
         char cmd[100];
         uint32_t dns_addr;
         uint32_t ip_addr;
+#endif
 
         if (_ipcp->state != IPCP_ENROLLED) {
                 LOG_DBGF("Won't register with non-enrolled IPCP.");
@@ -549,14 +633,23 @@ int ipcp_udp_name_reg(char * name)
                 return -1;
         }
 
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
         /* register application with DNS server */
 
         dns_addr = shim_data(_ipcp)->dns_addr;
         if (dns_addr != 0) {
                 ip_addr = shim_data(_ipcp)->ip_addr;
 
-                inet_ntop(AF_INET, &ip_addr, ipstr, INET_ADDRSTRLEN);
-                inet_ntop(AF_INET, &dns_addr, dnsstr, INET_ADDRSTRLEN);
+                if (inet_ntop(AF_INET, &ip_addr,
+                              ipstr, INET_ADDRSTRLEN) == NULL) {
+                        return -1;
+                }
+
+                if (inet_ntop(AF_INET, &dns_addr,
+                              dnsstr, INET_ADDRSTRLEN) == NULL) {
+                        return -1;
+                }
+
                 sprintf(cmd, "server %s\nupdate add %s %d A %s\nsend\nquit\n",
                         dnsstr, name, DNS_TTL, ipstr);
 
@@ -565,6 +658,7 @@ int ipcp_udp_name_reg(char * name)
                         return -1;
                 }
         }
+#endif
 
         LOG_DBG("Registered %s.", name);
 
@@ -573,26 +667,33 @@ int ipcp_udp_name_reg(char * name)
 
 int ipcp_udp_name_unreg(char * name)
 {
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
         char dnsstr[INET_ADDRSTRLEN];
         /* max DNS name length + max IP length + max command length */
         char cmd[100];
         uint32_t dns_addr;
+#endif
 
         if (strlen(name) > 24) {
                 LOG_ERR("DNS names cannot be longer than 24 chars.");
                 return -1;
         }
 
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
         /* unregister application with DNS server */
 
         dns_addr = shim_data(_ipcp)->dns_addr;
         if (dns_addr != 0) {
-                inet_ntop(AF_INET, &dns_addr, dnsstr, INET_ADDRSTRLEN);
+                if (inet_ntop(AF_INET, &dns_addr, dnsstr, INET_ADDRSTRLEN)
+                    == NULL) {
+                        return -1;
+                }
                 sprintf(cmd, "server %s\nupdate delete %s A\nsend\nquit\n",
                         dnsstr, name);
 
                 ddns_send(cmd);
         }
+#endif
 
         ipcp_data_del_reg_entry(_ipcp->data, name);
 
@@ -612,11 +713,13 @@ int ipcp_udp_flow_alloc(int               port_id,
         struct sockaddr_in r_saddr;
         struct sockaddr_in rf_saddr;
         int                fd;
-        int n;
-
-        char * recv_buf = NULL;
-
-        struct hostent * h;
+        int                n;
+        char *             recv_buf = NULL;
+        struct hostent *   h;
+        uint32_t           ip_addr = 0;
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
+        uint32_t           dns_addr = 0;
+#endif
 
         if (dst_name == NULL || src_ap_name == NULL || src_ae_name == NULL)
                 return -1;
@@ -644,22 +747,41 @@ int ipcp_udp_flow_alloc(int               port_id,
                 return -1;
         }
 
-        h = gethostbyname(dst_name);
-        if (h == NULL) {
-                LOG_DBGF("Could not resolve %s.", dst_name);
-                close(fd);
-                return -1;
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
+        dns_addr = shim_data(_ipcp)->dns_addr;
+        if (dns_addr != 0) {
+                ip_addr = ddns_resolve(dst_name, dns_addr);
+                if (ip_addr == 0) {
+                        LOG_DBGF("Could not resolve %s.", dst_name);
+                        close(fd);
+                        return -1;
+                }
+        } else {
+#endif
+                h = gethostbyname(dst_name);
+                if (h == NULL) {
+                        LOG_DBGF("Could not resolve %s.", dst_name);
+                        close(fd);
+                        return -1;
+                }
+
+                ip_addr = *((uint32_t *) (h->h_addr_list[0]));
+#ifdef CONFIG_OUROBOROS_ENABLE_DNS
         }
+#endif
 
         memset((char *) &r_saddr, 0, sizeof r_saddr);
         r_saddr.sin_family      = AF_INET;
-        r_saddr.sin_addr.s_addr = *((uint32_t *) (h->h_addr_list[0]));
+        r_saddr.sin_addr.s_addr = ip_addr;
         r_saddr.sin_port        = LISTEN_PORT;
 
 
         /* at least try to get the packet on the wire */
-        while (sendto(fd, dst_name, strlen(dst_name), 0,
+        if (sendto(fd, dst_name, strlen(dst_name), 0,
                       (struct sockaddr *) &r_saddr, sizeof r_saddr) < 0) {
+                LOG_ERR("Failed to send packet");
+                close(fd);
+                return -1;
         }
 
         /* wait for the other shim IPCP to respond */
@@ -677,11 +799,12 @@ int ipcp_udp_flow_alloc(int               port_id,
                     (struct sockaddr *) &rf_saddr,
                     sizeof rf_saddr)
             < 0) {
+                close(fd);
                 free(recv_buf);
                 return -1;
         }
 
-        if (!strcmp(recv_buf, dst_name))
+        if (strcmp(recv_buf, dst_name))
                 LOG_WARN("Incorrect echo from server");
 
         free(recv_buf);
@@ -692,6 +815,7 @@ int ipcp_udp_flow_alloc(int               port_id,
         if (_ap_instance->flows[fd].rb == NULL) {
                 LOG_ERR("Could not open N + 1 ringbuffer.");
                 close(fd);
+                return -1;
         }
 
         /* tell IRMd that flow allocation "worked" */
diff --git a/src/ipcpd/shim-udp/shim_udp_config.h.in b/src/ipcpd/shim-udp/shim_udp_config.h.in
new file mode 100644
index 00000000..71d269d8
--- /dev/null
+++ b/src/ipcpd/shim-udp/shim_udp_config.h.in
@@ -0,0 +1,29 @@
+/*
+ * Ouroboros - Copyright (C) 2016
+ *
+ * Configuration information specific for the shim UDP
+ *
+ *    Sander Vrijders <sander.vrijders@intec.ugent.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef OUROBOROS_SHIM_UDP_CONFIG
+#define OUROBOROS_SHIM_UDP_CONFIG
+
+#define NSUPDATE_EXEC "@NSUPDATE_EXECUTABLE@"
+#define NSLOOKUP_EXEC "@NSLOOKUP_EXECUTABLE@"
+
+#endif