Add support for SOCKS 5 proxies.

This only covers outgoing TCP connections, and supports only
username/password authentication or no authentication.

src/net_setup.c

@@ -422,7 +422,7 @@ static bool setup_myself(void) {
 				if(proxyuser && *proxyuser)
 					proxyuser = xstrdup(proxyuser);
 				if(proxypass && *proxypass)
-					proxyuser = xstrdup(proxypass);
+					proxypass = xstrdup(proxypass);
 				break;
 		}
 

src/protocol_auth.c

@@ -67,8 +67,54 @@ static bool send_proxyrequest(connection_t *c) {
 			c->tcplen = 8;
 			return send_meta(c, s4req, sizeof s4req);
 		}
+		case PROXY_SOCKS5: {
+			int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
+			c->tcplen = 2;
+			if(proxypass)
+				len += 3 + strlen(proxyuser) + strlen(proxypass);
+			char s5req[len];
+			int i = 0;
+			s5req[i++] = 5;
+			s5req[i++] = 1;
+			if(proxypass) {
+				s5req[i++] = 2;
+				s5req[i++] = 1;
+				s5req[i++] = strlen(proxyuser);
+				strcpy(s5req + i, proxyuser);
+				i += strlen(proxyuser);
+				s5req[i++] = strlen(proxypass);
+				strcpy(s5req + i, proxypass);
+				i += strlen(proxypass);
+				c->tcplen += 2;
+			} else {
+				s5req[i++] = 0;
+			}
+			s5req[i++] = 5;
+			s5req[i++] = 1;
+			s5req[i++] = 0;
+			if(c->address.sa.sa_family == AF_INET) {
+				s5req[i++] = 1;
+				memcpy(s5req + i, &c->address.in.sin_addr, 4);
+				i += 4;
+				memcpy(s5req + i, &c->address.in.sin_port, 2);
+				i += 2;
+				c->tcplen += 10;
+			} else if(c->address.sa.sa_family == AF_INET6) {
+				s5req[i++] = 3;
+				memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
+				i += 16;
+				memcpy(s5req + i, &c->address.in6.sin6_port, 2);
+				i += 2;
+				c->tcplen += 22;
+			} else {
+				logger(LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
+				return false;
+			}
+			if(i > len)
+				abort();
+			return send_meta(c, s5req, sizeof s5req);
+		}
 		case PROXY_SOCKS4A:
-		case PROXY_SOCKS5:
 			logger(LOG_ERR, "Proxy type not implemented yet");
 			return false;
 		default: