net: lws_wol() and lws_parse_mac()

Introduce a LWS_WITH_WOL and an api to wake a mac address, optionally with
an address bind to the local interface to go out on.

Add a helper to parse ascii mac addresses well, and add tests.

Also thanks to OgreTransporter
#3016

CMakeLists.txt

@@ -326,6 +326,7 @@ option(LWS_HTTP_HEADERS_ALL "Override header reduction optimization and include
 option(LWS_WITH_SUL_DEBUGGING "Enable zombie lws_sul checking on object deletion" OFF)
 option(LWS_WITH_PLUGINS_API "Build generic lws_plugins apis (see LWS_WITH_PLUGINS to also build protocol plugins)" OFF)
 option(LWS_WITH_CONMON "Collect introspectable connection latency stats on individual client connections" ON)
+option(LWS_WITH_WOL "Wake On Lan support" ON)
 option(LWS_WITHOUT_EVENTFD "Force using pipe instead of eventfd" OFF)
 if (UNIX OR WIN32)
 	option(LWS_WITH_CACHE_NSCOOKIEJAR "Build file-backed lws-cache-ttl that uses netscape cookie jar format (linux-only)" ON)

include/libwebsockets/lws-misc.h

@@ -1250,3 +1250,15 @@ lws_minilex_parse(const uint8_t *lex, int16_t *ps, const uint8_t c,
 
 LWS_VISIBLE LWS_EXTERN unsigned int
 lws_sigbits(uintptr_t u);
+
+/**
+ * lws_wol() - broadcast a magic WOL packet to MAC, optionally binding to if IP
+ *
+ * \p ctx: The lws context
+ * \p ip_or_NULL: The IP address to bind to at the client side, to send the
+ *                magic packet on.  If NULL, the system chooses, probably the
+ *                interface with the default route.
+ * \p mac_6_bytes: Points to a 6-byte MAC address to direct the magic packet to
+ */
+LWS_VISIBLE LWS_EXTERN int
+lws_wol(struct lws_context *ctx, const char *ip_or_NULL, uint8_t *mac_6_bytes);

include/libwebsockets/lws-network-helper.h

@@ -1,7 +1,7 @@
 /*
  * libwebsockets - small server side websockets and web server implementation
  *
- * Copyright (C) 2010 - 2020 Andy Green <[email protected]>
+ * Copyright (C) 2010 - 2023 Andy Green <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
@@ -246,4 +246,16 @@ lws_write_numeric_address(const uint8_t *ads, int size, char *buf, size_t len);
 LWS_VISIBLE LWS_EXTERN int
 lws_sa46_write_numeric_address(lws_sockaddr46 *sa46, char *buf, size_t len);
 
+/**
+ * lws_parse_mac() - convert XX:XX:XX:XX:XX:XX to 6-byte MAC address
+ *
+ * \param ads: mac address as XX:XX:XX:XX:XX:XX string
+ * \param result_6_bytes: result buffer to take 6 bytes
+ *
+ * Converts a string representation of a 6-byte hex mac address to a 6-byte
+ * array.
+ */
+LWS_VISIBLE LWS_EXTERN int
+lws_parse_mac(const char *ads, uint8_t *result_6_bytes);
+
 ///@}

lib/core-net/CMakeLists.txt

@@ -56,6 +56,11 @@ if (LWS_WITH_LWS_DSH)
 		core-net/lws-dsh.c)
 endif()
 
+if (LWS_WITH_WOL)
+	list(APPEND SOURCES
+		core-net/wol.c)
+endif()
+
 if (LWS_WITH_CLIENT)
 	list(APPEND SOURCES
 		core-net/client/client.c

lib/core-net/network.c

@@ -1104,3 +1104,62 @@ lws_system_get_state_manager(struct lws_context *context)
 	return &context->mgr_system;
 }
 #endif
+
+int
+lws_parse_mac(const char *ads, uint8_t *result_6_bytes)
+{
+	uint8_t *p = result_6_bytes;
+	struct lws_tokenize ts;
+	char t[3];
+	size_t n;
+	long u;
+
+	lws_tokenize_init(&ts, ads, LWS_TOKENIZE_F_NO_INTEGERS |
+				    LWS_TOKENIZE_F_MINUS_NONTERM);
+	ts.len = strlen(ads);
+
+	do {
+		ts.e = (int8_t)lws_tokenize(&ts);
+		switch (ts.e) {
+		case LWS_TOKZE_TOKEN:
+			if (ts.token_len != 2)
+				return -1;
+			if (p - result_6_bytes == 6)
+				return -2;
+			t[0] = ts.token[0];
+			t[1] = ts.token[1];
+			t[2] = '\0';
+			for (n = 0; n < 2; n++)
+				if (t[n] < '0' || t[n] > 'f' ||
+				    (t[n] > '9' && t[n] < 'A') ||
+				    (t[n] > 'F' && t[n] < 'a'))
+					return -1;
+			u = strtol(t, NULL, 16);
+			if (u > 0xff)
+				return -5;
+			*p++ = (uint8_t)u;
+			break;
+
+		case LWS_TOKZE_DELIMITER:
+			if (*ts.token != ':')
+				return -10;
+			if (p - result_6_bytes > 5)
+				return -11;
+			break;
+
+		case LWS_TOKZE_ENDED:
+			if (p - result_6_bytes != 6)
+				return -12;
+			return 0;
+
+		default:
+			lwsl_err("%s: malformed mac\n", __func__);
+
+			return -13;
+		}
+	} while (ts.e > 0);
+
+	lwsl_err("%s: ended on e %d\n", __func__, ts.e);
+
+	return -14;
+}

lib/core-net/wol.c

@@ -0,0 +1,88 @@
+/*
+ * libwebsockets - small server side websockets and web server implementation
+ *
+ * Copyright (C) 2010 - 2023 Andy Green <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "private-lib-core.h"
+
+#if defined(_WIN32) && !defined(IFHWADDRLEN)
+#define IFHWADDRLEN 6
+#endif
+
+int
+lws_wol(struct lws_context *ctx, const char *ip_or_NULL, uint8_t *mac_6_bytes)
+{
+        int n, m, ofs = 0, fd, optval = 1, ret = 1;
+        uint8_t pkt[17 * IFHWADDRLEN];
+        struct sockaddr_in addr;
+
+        fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+        if (fd < 0) {
+                lwsl_cx_err(ctx, "failed to open UDP, errno %d\n", errno);
+                goto bail;
+        }
+
+        if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST,
+                        (char *)&optval, sizeof(optval)) < 0) {
+                lwsl_cx_err(ctx, "failed to set broadcast, errno %d\n", errno);
+                goto bail;
+        }
+
+        /*
+         * Lay out the magic packet
+         */
+
+        for (n = 0; n < IFHWADDRLEN; n++)
+                pkt[ofs++] = 0xff;
+        for (m = 0; m < 16; m++)
+                for (n = 0; n < IFHWADDRLEN; n++)
+                        pkt[ofs++] = mac_6_bytes[n];
+
+        memset(&addr, 0, sizeof(addr));
+        addr.sin_family = AF_INET;
+        addr.sin_port   = htons(9);
+
+        if (!inet_aton(ip_or_NULL ? ip_or_NULL : "255.255.255.255",
+                        &addr.sin_addr)) {
+                lwsl_cx_err(ctx, "failed to convert broadcast ads, errno %d\n",
+                                 errno);
+                goto bail;
+        }
+
+        lwsl_cx_notice(ctx, "Sending WOL to %02X:%02X:%02X:%02X:%02X:%02X %s\n",
+                mac_6_bytes[0], mac_6_bytes[1], mac_6_bytes[2], mac_6_bytes[3],
+                mac_6_bytes[4], mac_6_bytes[5], ip_or_NULL ? ip_or_NULL : "");
+
+        if (sendto(fd, pkt, sizeof(pkt), 0, (struct sockaddr *)&addr,
+                        sizeof(addr)) < 0) {
+                lwsl_cx_err(ctx, "failed to sendto broadcast ads, errno %d\n",
+                                 errno);
+                goto bail;
+        }
+
+        ret = 0;
+
+bail:
+        close(fd);
+
+        return ret;
+}

minimal-examples-lowlevel/api-tests/api-test-async-dns/main.c

@@ -425,6 +425,7 @@ main(int argc, const char **argv)
 {
 	int n = 1, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE;
 	struct lws_context_creation_info info;
+	uint8_t mac[6];
 	const char *p;
 
 	/* fixup dynamic target addresses we're testing against */
@@ -517,6 +518,40 @@ main(int argc, const char **argv)
 		ok++;
 	}
 
+	/* mac address parser tests */
+
+	if (lws_parse_mac("11:ff:ce:CE:22:33", mac)) {
+		lwsl_err("%s: mac fail 1\n", __func__);
+		lwsl_hexdump_notice(mac, 6);
+		fail++;
+	} else
+		if (mac[0] != 0x11 || mac[1] != 0xff || mac[2] != 0xce ||
+		    mac[3] != 0xce || mac[4] != 0x22 || mac[5] != 0x33) {
+			lwsl_err("%s: mac fail 2\n", __func__);
+			lwsl_hexdump_notice(mac, 6);
+			fail++;
+		}
+	if (!lws_parse_mac("11:ff:ce:CE:22:3", mac)) {
+		lwsl_err("%s: mac fail 3\n", __func__);
+		lwsl_hexdump_notice(mac, 6);
+		fail++;
+	}
+	if (!lws_parse_mac("11:ff:ce:CE:22", mac)) {
+		lwsl_err("%s: mac fail 4\n", __func__);
+		lwsl_hexdump_notice(mac, 6);
+		fail++;
+	}
+	if (!lws_parse_mac("11:ff:ce:CE:22:", mac)) {
+		lwsl_err("%s: mac fail 5\n", __func__);
+		lwsl_hexdump_notice(mac, 6);
+		fail++;
+	}
+	if (!lws_parse_mac("11:ff:ce:CE22", mac)) {
+		lwsl_err("%s: mac fail 6\n", __func__);
+		lwsl_hexdump_notice(mac, 6);
+		fail++;
+	}
+
 #if !defined(LWS_WITH_IPV6)
 	_exp -= 2;
 #endif

minimal-examples-lowlevel/raw/minimal-raw-wol/CMakeLists.txt

@@ -0,0 +1,23 @@
+project(lws-minimal-raw-wol C)
+cmake_minimum_required(VERSION 3.6)
+find_package(libwebsockets CONFIG REQUIRED)
+list(APPEND CMAKE_MODULE_PATH ${LWS_CMAKE_DIR})
+include(CheckCSourceCompiles)
+include(LwsCheckRequirements)
+
+set(SAMP lws-minimal-raw-wol)
+set(SRCS minimal-raw-wol.c)
+
+set(requirements 1)
+require_lws_config(LWS_WITH_WOL 1 requirements)
+
+if (requirements)
+	add_executable(${SAMP} ${SRCS})
+
+	if (websockets_shared)
+		target_link_libraries(${SAMP} websockets_shared ${LIBWEBSOCKETS_DEP_LIBS})
+		add_dependencies(${SAMP} websockets_shared)
+	else()
+		target_link_libraries(${SAMP} websockets ${LIBWEBSOCKETS_DEP_LIBS})
+	endif()
+endif()

minimal-examples-lowlevel/raw/minimal-raw-wol/README.md

@@ -0,0 +1,34 @@
+# lws minimal raw wol
+
+This example shows how to send a Wake On Lan magic packet to a given mac.
+
+## build
+
+```
+ $ cmake . && make
+```
+
+## usage
+
+```
+$ bin/lws-minimal-raw-wol b4:2e:99:a9:22:90
+[2023/11/09 12:25:24:2255] N: lws_create_context: LWS: 4.3.99-v4.3.0-295-g60d671c7, NET CLI SRV H1 H2 WS SS-JSON-POL ConMon ASYNC_DNS IPv6-absent
+[2023/11/09 12:25:24:2256] N: __lws_lc_tag:  ++ [wsi|0|pipe] (1)
+[2023/11/09 12:25:24:2256] N: __lws_lc_tag:  ++ [vh|0|netlink] (1)
+[2023/11/09 12:25:24:2256] N: __lws_lc_tag:  ++ [vh|1|system||-1] (2)
+[2023/11/09 12:25:24:2257] N: __lws_lc_tag:  ++ [wsisrv|0|system|asyncdns] (1)
+[2023/11/09 12:25:24:2257] N: __lws_lc_tag:  ++ [wsisrv|1|system|asyncdns] (2)
+[2023/11/09 12:25:24:2257] N: __lws_lc_tag:  ++ [vh|2|default||0] (3)
+[2023/11/09 12:25:24:2257] N: [vh|2|default||0]: lws_socket_bind: source ads 0.0.0.0
+[2023/11/09 12:25:24:2257] N: __lws_lc_tag:  ++ [wsi|1|listen|default||33749] (2)
+[2023/11/09 12:25:24:2257] N: lws_wol: Sending WOL to B4:2E:99:A9:22:90
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [wsi|0|pipe] (1) 190μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [wsi|1|listen|default||33749] (0) 80μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [wsisrv|1|system|asyncdns] (1) 118μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [wsisrv|0|system|asyncdns] (0) 155μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [vh|0|netlink] (2) 198μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [vh|1|system||-1] (1) 182μs
+[2023/11/09 12:25:24:2258] N: __lws_lc_untag:  -- [vh|2|default||0] (0) 125μs
+
+$
+```

minimal-examples-lowlevel/raw/minimal-raw-wol/minimal-raw-wol.c

@@ -0,0 +1,52 @@
+/*
+ * lws-minimal-raw-wol
+ *
+ * Written in 2010-2023 by Andy Green <[email protected]>
+ *
+ * This file is made available under the Creative Commons CC0 1.0
+ * Universal Public Domain Dedication.
+ *
+ * This demonstrates using lws_wol()
+ */
+
+#include <libwebsockets.h>
+#include <net/if.h>
+
+int main(int argc, const char **argv)
+{
+	struct lws_context_creation_info info;
+	struct lws_context *ctx;
+	const char *p, *ip = NULL;
+	uint8_t mac[IFHWADDRLEN];
+	int ret = 1;
+
+	memset(&info, 0, sizeof info);
+	lws_cmdline_option_handle_builtin(argc, argv, &info);
+
+	if ((p = lws_cmdline_option(argc, argv, "-ip")))
+		ip = p;
+
+	if (argc < 2) {
+		lwsl_user("lws-minimal-raw-wol XX:XX:XX:XX:XX:XX [-ip interface IP]\n");
+		goto bail1;
+	}
+
+	if (lws_parse_mac(argv[1], mac)) {
+		lwsl_user("Failed to parse mac '%s'\n", argv[1]);
+		goto bail1;
+	}
+
+	ctx = lws_create_context(&info);
+	if (!ctx) {
+		lwsl_err("lws init failed\n");
+		goto bail1;
+	}
+
+	if (!lws_wol(ctx, ip, mac))
+		ret = 0;
+
+	lws_context_destroy(ctx);
+
+bail1:
+	return ret;
+}