Proxy.C

 
//
// Copyright (c) 2025, Isode Limited, London, England.
// All rights reserved.
// 
// Acquisition and use of this software and related materials for any
// purpose requires a written licence agreement from Isode
// Limited, or a written licence from an organisation licenced by Isode
// Limited to grant such a licence.
//
 
#include <event/lib/Proxy.h>
#include <cctype>
 
namespace Stream {
    // These are utilities for implementing the PROXY protocol,
    // https://github.com/haproxy/haproxy/blob/master/doc/proxy-protocol.txt
 
    bool read_ipv4(string_iter& start, const string_iter end, std::uint32_t& addr)
    {
        auto p(start);
        while (p != end && (std::isdigit(*p) || '.' == *p)) {
            ++p;
        }
        if (!(p == end || ' ' == *p)) {
            return false;
        }
        std::string tmp(start, p);
        int r = inet_pton(AF_INET, tmp.c_str(), &addr);
        if (1 == r) {
            start = (p == end) ? p : p+1;
            return true;
        }
        return false;
    }
 
    bool read_ipv6(string_iter& start, const string_iter end, in6_addr & addr)
    {
        auto p(start);
        while (p != end && (std::isdigit(*p) || ':' == *p || ('a' <= *p && 'f' >= *p) ||
                            ('A' <= *p && 'F' >= *p))) {
            ++p;
        }
        if (!(p == end || ' ' == *p)) {
            return false;
        }
        std::string tmp(start, p);
        int r = inet_pton(AF_INET6, tmp.c_str(), &addr);
        if (1 == r) {
            start = (p == end) ? p : p+1;
            return true;
        }
        return false;
    }
 
    bool read_port(string_iter& start, string_iter end, std::uint16_t& port)
    {
        auto p(start);
        bool in_digits = false;
        while (p != end && isdigit(*p)) {
            in_digits = true;
            ++p;
        }
        if (!in_digits) {
            return false;
        }
        if (!(p == end || ' ' == *p)) {
            return false;
        }
        const std::string port_str(start, p);
        if (port_str.length() > 5) {
            return false;
        }
        auto port_int = std::atoi(port_str.c_str());
        if (port_int > 65535) {
            return false;
        }
        port = port_int;
        start = (p == end) ? p : p+1;
        return true;
    }
 
    bool read_proxy_ipv4(const std::string& addr, ipv4_addr& proxy_header)
    {
        auto end(addr.end());
        auto p(addr.begin());
        if (!read_ipv4(p, end, proxy_header.src_addr)) {
            return false;
        }
        if (!read_ipv4(p, end, proxy_header.dst_addr)) {
            return false;
        }
        if (!read_port(p, end, proxy_header.src_port)) {
            return false;
        }
        if (!read_port(p, end, proxy_header.dst_port)) {
            return false;
        }
        return true;
    }
 
    bool read_proxy_ipv6(const std::string& addr, ipv6_addr& proxy_header)
    {
        auto end(addr.end());
        auto p(addr.begin());
        if (!read_ipv6(p, end, proxy_header.src_addr)) {
            return false;
        }
        if (!read_ipv6(p, end, proxy_header.dst_addr)) {
            return false;
        }
        if (!read_port(p, end, proxy_header.src_port)) {
            return false;
        }
        if (!read_port(p, end, proxy_header.dst_port)) {
            return false;
        }
        return true;
    }
}