Initial socks5 client & server implementation

PUBLISHED_FROM=05d3cca6223c963e7ae89dde3628fa8fad46e6bd

examples/socks_server/Makefile

+PROG = socks_server
+# NOTE(lsm): -DMG_ENABLE_IPV6 won't work for the mingw build
+MODULE_CFLAGS = -DMG_ENABLE_SOCKS=1 # -DMG_ENABLE_DEBUG=1
+#SSL_LIB=openssl
+include ../examples.mk

examples/socks_server/socks_server.c

+/*
+ * Copyright (c) 2017 Cesanta Software Limited
+ * All rights reserved
+ *
+ * Use curl to test, e.g.
+ * curl -i --socks5 127.0.0.1:1080 www.met.ie
+ */
+
+#include "mongoose.h"
+
+static const char *s_listening_addr = "1080";
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_connection *c;
+
+  mg_mgr_init(&mgr, NULL);
+
+  if ((c = mg_bind(&mgr, s_listening_addr, NULL)) == NULL) {
+    fprintf(stderr, "mg_bind(%s) failed\n", s_listening_addr);
+    exit(EXIT_FAILURE);
+  }
+  mg_set_protocol_socks(c);
+
+  printf("Starting socks5 proxy server on %s\n", s_listening_addr);
+  for (;;) {
+    mg_mgr_poll(&mgr, 1000);
+  }
+  mg_mgr_free(&mgr);
+
+  return 0;
+}

mongoose.h

@@ -3029,6 +3029,10 @@ struct {								\
 #define MG_ENABLE_MQTT 1
 #endif
 
+#ifndef MG_ENABLE_SOCKS
+#define MG_ENABLE_SOCKS 0
+#endif
+
 #ifndef MG_ENABLE_MQTT_BROKER
 #define MG_ENABLE_MQTT_BROKER 0
 #endif
@@ -6032,3 +6036,69 @@ struct mg_connection *mg_sntp_get_time(struct mg_mgr *mgr,
 #endif
 
 #endif /* CS_MONGOOSE_SRC_SNTP_H_ */
+#ifdef MG_MODULE_LINES
+#line 1 "mongoose/src/socks.h"
+#endif
+/*
+ * Copyright (c) 2017 Cesanta Software Limited
+ * All rights reserved
+ */
+
+#ifndef CS_MONGOOSE_SRC_SOCKS_H_
+#define CS_MONGOOSE_SRC_SOCKS_H_
+
+#if MG_ENABLE_SOCKS
+
+#define MG_SOCKS_VERSION 5
+
+/* SOCKS5 handshake methods */
+enum mg_socks_handshake_method {
+  MG_SOCKS_HANDSHAKE_NOAUTH = 0,     /* Handshake method - no authentication */
+  MG_SOCKS_HANDSHAKE_GSSAPI = 1,     /* Handshake method - GSSAPI auth */
+  MG_SOCKS_HANDSHAKE_USERPASS = 2,   /* Handshake method - user/password auth */
+  MG_SOCKS_HANDSHAKE_FAILURE = 0xff, /* Handshake method - failure */
+};
+
+/* SOCKS5 commands */
+enum mg_socks_command {
+  MG_SOCKS_CMD_CONNECT = 1,        /* Command: CONNECT */
+  MG_SOCKS_CMD_BIND = 2,           /* Command: BIND */
+  MG_SOCKS_CMD_UDP_ASSOCIATE = 3,  /* Command: UDP ASSOCIATE */
+};
+
+/* SOCKS5 address types */
+enum mg_socks_address_type {
+  MG_SOCKS_ADDR_IPV4 = 1,          /* Address type: IPv4 */
+  MG_SOCKS_ADDR_DOMAIN = 3,        /* Address type: Domain name */
+  MG_SOCKS_ADDR_IPV6 = 4,          /* Address type: IPv6 */
+};
+
+/* SOCKS5 response codes */
+enum mg_socks_response {
+  MG_SOCKS_SUCCESS = 0,            /* Response: success */
+  MG_SOCKS_FAILURE = 1,            /* Response: failure */
+  MG_SOCKS_NOT_ALLOWED = 2,        /* Response: connection not allowed */
+  MG_SOCKS_NET_UNREACHABLE = 3,    /* Response: network unreachable */
+  MG_SOCKS_HOST_UNREACHABLE = 4,   /* Response: network unreachable */
+  MG_SOCKS_CONN_REFUSED = 5,       /* Response: network unreachable */
+  MG_SOCKS_TTL_EXPIRED = 6,        /* Response: network unreachable */
+  MG_SOCKS_CMD_NOT_SUPPORTED = 7,  /* Response: network unreachable */
+  MG_SOCKS_ADDR_NOT_SUPPORTED = 8, /* Response: network unreachable */
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Turn the connection into the SOCKS server */
+void mg_set_protocol_socks(struct mg_connection *c);
+
+/* Create socks tunnel for the client connection */
+struct mg_iface *mg_socks_mk_iface(struct mg_mgr *, const char *proxy_addr);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif
+#endif