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/*
* Authored by Alex Hultman, 2018-2020.
* Intellectual property of third-party.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This module implements The PROXY Protocol v2 */
#ifndef UWS_PROXY_PARSER_H
#define UWS_PROXY_PARSER_H
#ifdef UWS_WITH_PROXY
namespace uWS {
struct proxy_hdr_v2 {
uint8_t sig[12]; /* hex 0D 0A 0D 0A 00 0D 0A 51 55 49 54 0A */
uint8_t ver_cmd; /* protocol version and command */
uint8_t fam; /* protocol family and address */
uint16_t len; /* number of following bytes part of the header */
};
union proxy_addr {
struct { /* for TCP/UDP over IPv4, len = 12 */
uint32_t src_addr;
uint32_t dst_addr;
uint16_t src_port;
uint16_t dst_port;
} ipv4_addr;
struct { /* for TCP/UDP over IPv6, len = 36 */
uint8_t src_addr[16];
uint8_t dst_addr[16];
uint16_t src_port;
uint16_t dst_port;
} ipv6_addr;
};
/* Byte swap for little-endian systems */
/* Todo: This functions should be shared with the one in WebSocketProtocol.h! */
template <typename T>
T _cond_byte_swap(T value) {
uint32_t endian_test = 1;
if (*((char *)&endian_test)) {
union {
T i;
uint8_t b[sizeof(T)];
} src = { value }, dst;
for (unsigned int i = 0; i < sizeof(value); i++) {
dst.b[i] = src.b[sizeof(value) - 1 - i];
}
return dst.i;
}
return value;
}
struct ProxyParser {
private:
union proxy_addr addr;
/* Default family of 0 signals no proxy address */
uint8_t family = 0;
public:
/* Returns 4 or 16 bytes source address */
std::string_view getSourceAddress() {
// UNSPEC family and protocol
if (family == 0) {
return {};
}
if ((family & 0xf0) >> 4 == 1) {
/* Family 1 is INET4 */
return {(char *) &addr.ipv4_addr.src_addr, 4};
} else {
/* Family 2 is INET6 */
return {(char *) &addr.ipv6_addr.src_addr, 16};
}
}
/* Returns [done, consumed] where done = false on failure */
std::pair<bool, unsigned int> parse(std::string_view data) {
/* We require at least four bytes to determine protocol */
if (data.length() < 4) {
return {false, 0};
}
/* HTTP can never start with "\r\n\r\n", but PROXY always does */
if (memcmp(data.data(), "\r\n\r\n", 4)) {
/* This is HTTP, so be done */
return {true, 0};
}
/* We assume we are parsing PROXY V2 here */
/* We require 16 bytes here */
if (data.length() < 16) {
return {false, 0};
}
/* Header is 16 bytes */
struct proxy_hdr_v2 header;
memcpy(&header, data.data(), 16);
if (memcmp(header.sig, "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A", 12)) {
/* This is not PROXY protocol at all */
return {false, 0};
}
/* We only support version 2 */
if ((header.ver_cmd & 0xf0) >> 4 != 2) {
return {false, 0};
}
//printf("Version: %d\n", (header.ver_cmd & 0xf0) >> 4);
//printf("Command: %d\n", (header.ver_cmd & 0x0f));
/* We get length in network byte order (todo: share this function with the rest) */
uint16_t hostLength = _cond_byte_swap<uint16_t>(header.len);
/* We must have all the data available */
if (data.length() < 16u + hostLength) {
return {false, 0};
}
/* Payload cannot be more than sizeof proxy_addr */
if (sizeof(proxy_addr) < hostLength) {
return {false, 0};
}
//printf("Family: %d\n", (header.fam & 0xf0) >> 4);
//printf("Transport: %d\n", (header.fam & 0x0f));
/* We have 0 family by default, and UNSPEC is 0 as well */
family = header.fam;
/* Copy payload */
memcpy(&addr, data.data() + 16, hostLength);
/* We consumed everything */
return {true, 16 + hostLength};
}
};
}
#endif
#endif // UWS_PROXY_PARSER_H