Fixed issue #2079: Add pseudo hosts xdebug://gateway and xdebug://nameserver

config.m4

@@ -97,7 +97,7 @@ if test "$PHP_XDEBUG" != "no"; then
   XDEBUG_LIB_SOURCES="src/lib/usefulstuff.c src/lib/compat.c src/lib/crc32.c src/lib/file.c src/lib/hash.c src/lib/headers.c src/lib/lib.c src/lib/llist.c src/lib/log.c src/lib/set.c src/lib/str.c src/lib/timing.c src/lib/var.c src/lib/var_export_html.c src/lib/var_export_line.c src/lib/var_export_text.c src/lib/var_export_xml.c src/lib/xml.c"
 
   XDEBUG_COVERAGE_SOURCES="src/coverage/branch_info.c src/coverage/code_coverage.c"
-  XDEBUG_DEBUGGER_SOURCES="src/debugger/com.c src/debugger/debugger.c src/debugger/handler_dbgp.c src/debugger/handlers.c"
+  XDEBUG_DEBUGGER_SOURCES="src/debugger/com.c src/debugger/debugger.c src/debugger/handler_dbgp.c src/debugger/handlers.c src/debugger/ip_info.c"
   XDEBUG_DEVELOP_SOURCES="src/develop/develop.c src/develop/monitor.c src/develop/php_functions.c src/develop/stack.c src/develop/superglobals.c"
   XDEBUG_GCSTATS_SOURCES="src/gcstats/gc_stats.c"
   XDEBUG_PROFILER_SOURCES="src/profiler/profiler.c"

package.xml

@@ -166,6 +166,8 @@ Thu, Apr 08, 2021 - Xdebug 3.0.4
      <file name="handlers.h" role="src" />
      <file name="handler_dbgp.c" role="src" />
      <file name="handler_dbgp.h" role="src" />
+     <file name="ip_info.c" role="src" />
+     <file name="ip_info.h" role="src" />
     </dir>
     <dir name="gcstats">
      <file name="gc_stats.c" role="src" />

src/base/base.c

@@ -1173,6 +1173,7 @@ int read_systemd_private_tmp_directory(char **private_tmp)
 
 	/* Clean up and return */
 	xdebug_arg_dtor(lines);
+	fclose(mountinfo_fd);
 	return retval;
 }
 #endif

src/debugger/com.c

@@ -50,6 +50,7 @@
 
 #include "debugger_private.h"
 #include "handler_dbgp.h"
+#include "ip_info.h"
 #include "lib/crc32.h"
 #include "lib/log.h"
 
@@ -134,6 +135,46 @@ void set_keepalive_options(int fd)
 }
 #endif  // !WIN32 && !WINNT
 
+static char* resolve_pseudo_hosts(const char *requested_hostname)
+{
+#if __linux__
+	/* Does it start with 'xdebug://' ? */
+	if (strncmp(requested_hostname, "xdebug://", strlen("xdebug://")) != 0) {
+		return NULL;
+	}
+
+	/* Check for 'gateway' pseudo host */
+	if (strcmp(requested_hostname, "xdebug://gateway") == 0) {
+		char *gateway = xdebug_get_gateway_ip();
+
+		if (!gateway) {
+			xdebug_log_ex(XLOG_CHAN_DEBUG, XLOG_WARN, "GATEWAY", "Could not find network gateway to use for 'gateway' pseudo-host.");
+			return NULL;
+		}
+
+		xdebug_log(XLOG_CHAN_DEBUG, XLOG_INFO, "Found 'gateway' pseudo-host, with IP address '%s'.", gateway);
+		return gateway;
+	}
+
+	/* Check for 'nameserver' pseudo host */
+	if (strcmp(requested_hostname, "xdebug://nameserver") == 0) {
+		char *gateway = xdebug_get_private_nameserver();
+
+		if (!gateway) {
+			xdebug_log_ex(XLOG_CHAN_DEBUG, XLOG_WARN, "NAMESERVER", "Could not find a private network nameserver for 'nameserver' pseudo-host.");
+			return NULL;
+		}
+
+		xdebug_log(XLOG_CHAN_DEBUG, XLOG_INFO, "Found 'nameserver' pseudo-host, with IP address '%s'.", gateway);
+		return gateway;
+	}
+
+	xdebug_log_ex(XLOG_CHAN_DEBUG, XLOG_WARN, "UNKNOWN-PSEUDO", "Unknown pseudo-host: '%s', only 'gateway' or 'nameserver' are supported.", requested_hostname + strlen("xdebug://"));
+#endif
+
+	return NULL;
+}
+
 static int xdebug_create_socket(const char *hostname, int dport, int timeout)
 {
 	struct addrinfo            hints;
@@ -332,7 +373,7 @@ static int xdebug_create_socket(const char *hostname, int dport, int timeout)
 		break;
 	}
 
-	/* Free the result returned by getaddrinfo */
+	/* Free the result returned by getaddrinfo, as well as the duplicated hostname */
 	freeaddrinfo(remote);
 
 	/* If we got a socket, set the option "No delay" to true (1) */
@@ -376,6 +417,17 @@ static void xdebug_init_normal_debugger(xdebug_str *connection_attempts)
 	const char *header = NULL;
 
 	if (!XINI_DBG(discover_client_host)) {
+		char *pseudo_hostname = resolve_pseudo_hosts(XINI_DBG(client_host));
+
+		if (pseudo_hostname) {
+			xdebug_str_add_fmt(connection_attempts, "%s:%ld (through xdebug.client_host/xdebug.client_port, from %s)", pseudo_hostname, XINI_DBG(client_port), XINI_DBG(client_host));
+			xdebug_log(XLOG_CHAN_DEBUG, XLOG_INFO, "Connecting to resolved address/port: %s:%ld.", pseudo_hostname, (long int) XINI_DBG(client_port));
+
+			XG_DBG(context).socket = xdebug_create_socket(pseudo_hostname, XINI_DBG(client_port), XINI_DBG(connect_timeout_ms));
+			xdfree(pseudo_hostname);
+			return;
+		}
+
 		xdebug_str_add_fmt(connection_attempts, "%s:%ld (through xdebug.client_host/xdebug.client_port)", XINI_DBG(client_host), XINI_DBG(client_port));
 		xdebug_log(XLOG_CHAN_DEBUG, XLOG_INFO, "Connecting to configured address/port: %s:%ld.", XINI_DBG(client_host), (long int) XINI_DBG(client_port));
 

src/debugger/ip_info.c

@@ -0,0 +1,283 @@
+/*
+   +----------------------------------------------------------------------+
+   | Xdebug                                                               |
+   +----------------------------------------------------------------------+
+   | Copyright (c) 2002-2022 Derick Rethans                               |
+   +----------------------------------------------------------------------+
+   | This source file is subject to version 1.01 of the Xdebug license,   |
+   | that is bundled with this package in the file LICENSE, and is        |
+   | available at through the world-wide-web at                           |
+   | https://xdebug.org/license.php                                       |
+   | If you did not receive a copy of the Xdebug license and are unable   |
+   | to obtain it through the world-wide-web, please send a note to       |
+   | derick@xdebug.org so we can mail you a copy immediately.             |
+   +----------------------------------------------------------------------+
+ */
+#ifdef __linux__
+
+#include "php_xdebug.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <linux/rtnetlink.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+
+#define BUFFER_SIZE		4096
+
+static char *convert_to_quad(int domain, void *buf)
+{
+	char *ip = xdcalloc(1, INET6_ADDRSTRLEN + 1);
+
+	inet_ntop(domain, buf, ip, INET6_ADDRSTRLEN);
+
+	return ip;
+}
+
+static int get_ip(int fd, struct sockaddr_nl *sa, int domain)
+{
+	char              buf[BUFFER_SIZE];
+	struct nlmsghdr  *nl;
+	struct ifaddrmsg *ifa;
+	struct iovec      iov = { 0 };
+	struct msghdr     msg = { 0 };
+	int               r;
+
+	memset(buf, 0, BUFFER_SIZE);
+
+	/* Assemble the message according to the netlink protocol */
+	nl = (struct nlmsghdr*)buf;
+	nl->nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+	nl->nlmsg_type = RTM_GETADDR;
+	nl->nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
+
+	ifa = (struct ifaddrmsg*)NLMSG_DATA(nl);
+	ifa->ifa_family = domain; // We only get IPv4 address here
+
+	/* Prepare struct msghdr for sending */
+	iov.iov_base = nl;
+	iov.iov_len = nl->nlmsg_len;
+	msg.msg_name = sa;
+	msg.msg_namelen = sizeof(*sa);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_flags = 0;
+
+	/* Send netlink message to kernel */
+	r = sendmsg(fd, &msg, 0);
+	return (r < 0) ? -1 : 0;
+}
+
+static int get_msg(int fd, struct sockaddr_nl *sa, void *buf, size_t len)
+{
+	struct iovec iov;
+	struct msghdr msg;
+
+	iov.iov_base = buf;
+	iov.iov_len = len;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_name = sa;
+	msg.msg_namelen = sizeof(*sa);
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	return recvmsg(fd, &msg, 0);
+}
+
+static char *parse_ifa_msg(struct ifaddrmsg *ifa, void *buf, size_t len, const char *wanted_iface)
+{
+	char           ifname[IF_NAMESIZE];
+	struct rtattr *rta = NULL;
+	int            fa  = ifa->ifa_family;
+
+	if_indextoname(ifa->ifa_index, ifname);
+
+	if (strcmp(ifname, wanted_iface) != 0) {
+		return NULL;
+	}
+
+	for (rta = (struct rtattr*)buf; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
+		if (rta->rta_type == IFA_ADDRESS) {
+			return convert_to_quad(fa, RTA_DATA(rta));
+		}
+	}
+
+	return NULL;
+}
+
+static uint32_t parse_nl_msg(void *buf, size_t len, const char *iface, char **if_address)
+{
+	struct nlmsghdr *nl = NULL;
+	uint32_t nlmsg_type = NLMSG_ERROR;
+
+	for (
+		nl = (struct nlmsghdr*)buf;
+		NLMSG_OK(nl, (uint32_t)len) && nl->nlmsg_type != NLMSG_DONE;
+		nl = NLMSG_NEXT(nl, len)
+	) {
+		nlmsg_type = nl->nlmsg_type;
+
+		if (nl->nlmsg_type == NLMSG_ERROR) {
+			return -1;
+		}
+
+		if (nl->nlmsg_type == RTM_NEWADDR) {
+			struct ifaddrmsg *ifa;
+			ifa = (struct ifaddrmsg*)NLMSG_DATA(nl);
+
+			if (*if_address == NULL) {
+				*if_address = parse_ifa_msg(ifa, IFA_RTA(ifa), IFA_PAYLOAD(nl), iface);
+				if (*if_address) {
+					return NLMSG_DONE;
+				}
+			}
+			continue;
+		}
+	}
+	return nlmsg_type;
+}
+
+char *xdebug_get_ip_for_interface(const char *iface)
+{
+	char      buf[BUFFER_SIZE];
+	int       fd = 0, len = 0;
+	char     *if_address = NULL;
+	uint32_t  nl_msg_type = NLMSG_DONE;
+	struct    sockaddr_nl sa;
+
+	/* Create a socket with the AF_NETLINK domain */
+	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (fd < 0) {
+		return NULL;
+	}
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	len = get_ip(fd, &sa, AF_INET); // For IPv6: use AF_INET6 instead
+	if (len < 0) {
+		return NULL;
+	}
+
+	do {
+		len = get_msg(fd, &sa, buf, BUFFER_SIZE);
+		if (len < 0) {
+			return NULL;
+		}
+
+		nl_msg_type = parse_nl_msg(buf, len, iface, &if_address);
+	} while (nl_msg_type != NLMSG_DONE && nl_msg_type != NLMSG_ERROR);
+
+	return if_address;
+}
+
+/***/
+
+static int get_gateway_and_iface(in_addr_t *addr, char *interface)
+{
+    long  destination, gateway;
+    char  iface[IF_NAMESIZE];
+    char  buf[BUFFER_SIZE];
+    FILE *file;
+
+    memset(iface, 0, sizeof(iface));
+    memset(buf, 0, sizeof(buf));
+
+    file = fopen("/proc/net/route", "r");
+    if (!file) {
+        return 0;
+	}
+
+    while (fgets(buf, sizeof(buf), file)) {
+        if (sscanf(buf, "%s %lx %lx", iface, &destination, &gateway) == 3) {
+            if (destination == 0) { /* default */
+                *addr = gateway;
+                strcpy(interface, iface);
+                fclose(file);
+                return 1;
+            }
+        }
+    }
+
+    /* default route not found */
+    if (file) {
+        fclose(file);
+	}
+    return 0;
+}
+
+char *xdebug_get_gateway_ip(void)
+{
+    in_addr_t addr = 0;
+    char      iface[IF_NAMESIZE];
+
+    memset(iface, 0, sizeof(iface));
+
+    if (get_gateway_and_iface(&addr, iface)) {
+		return xdstrdup(inet_ntoa(*(struct in_addr *) &addr));
+	}
+
+    return NULL;
+}
+
+/***/
+
+char *xdebug_get_private_nameserver(void)
+{
+	res_state res = malloc(sizeof(struct __res_state));
+	in_addr_t ns_addr = 0;
+	char nameserver_buf[20];
+	char *nameserver = NULL;
+
+	res_ninit(res);
+	if (res->nscount > 0 && res->nsaddr_list[0].sin_family == AF_INET) {
+		ns_addr = res->nsaddr_list[0].sin_addr.s_addr;
+		/* Only allow private networks */
+		if (
+			((ns_addr & 0x000000ff) == 0x0000000a) || // 10.x.x.x/24
+			((ns_addr & 0x0000f0ff) == 0x000010ac) || // 172.16.x.x/20
+			((ns_addr & 0x0000ffff) == 0x0000a8c0) || // 192.168.x.x/16
+			((ns_addr & 0x000000ff) == 0x0000007f)    // 127.x.x.x/8
+		)
+		{
+			snprintf(
+				nameserver_buf, 16, "%d.%d.%d.%d",
+				(ns_addr & 0xff),
+				(ns_addr & 0xff00) >> 8,
+				(ns_addr & 0xff0000) >> 16,
+				(ns_addr & 0xff000000) >> 24
+			);
+			nameserver = xdstrdup(nameserver_buf);
+		}
+	}
+	res_nclose(res);
+	free(res);
+
+	return nameserver;
+}
+
+
+# if 0
+int main(int argc, char *argv[])
+{
+	char *gateway_address = xdebug_get_gateway_ip();
+	char *ip_address      = xdebug_get_ip_for_interface(argv[1]);
+
+	printf("Gateway: %s\n", gateway_address);
+	printf("IP: %s\n", ip_address);
+
+	free(ip_address);
+	free(gateway_address);
+}
+# endif // int main
+
+#endif // __linux__