proxyprotocol.c

/*
# proxyprotocol: Support for HAProxy's proxyprotocol
#
# Copyright (C) 2025  Yves Rutschle
# 
# This program is free software; you can redistribute it
# and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later
# version.
# 
# This program is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
# PURPOSE.  See the GNU General Public License for more
# details.
# 
# The full text for the General Public License is here:
# http://www.gnu.org/licenses/gpl.html

*/

#include "config.h"

#ifdef HAVE_PROXYPROTOCOL

#include <proxy_protocol.h>
#include "common.h"
#include "log.h"


/* Converts socket family to libproxyprotocol family */
static int family_to_pp(int af_family)
{
    switch (af_family) {
    case AF_INET:
        return ADDR_FAMILY_INET;

    case AF_INET6:
        return ADDR_FAMILY_INET6;

    case AF_UNIX:
        return ADDR_FAMILY_UNIX;

    default:
        print_message(msg_int_error, "Unknown internal socket family %d\n", af_family);
        return -1;
    }
}

typedef char libpp_addr[108]; /* This is hardcoded in libproxyprotocol/proxy_protocol.h */

/* Fills *addr, *host and *serv with the connection information corresponding
 * to fd. *host is the IP address as string and *serv is the service (port)
 * */
static int get_peer_info(int fd, struct addrinfo* addr, libpp_addr* host, uint16_t* serv)
{
    char serv_str[NI_MAXSERV];
    int res;

    res = getpeername(fd, addr->ai_addr, &addr->ai_addrlen);
    CHECK_RES_RETURN(res, "getpeername", -1);

    res = getnameinfo(addr->ai_addr, addr->ai_addrlen,
                      (char*)host, sizeof(*host),
                      serv_str, sizeof(serv_str),
                      NI_NUMERICHOST | NI_NUMERICSERV );
    CHECK_RES_RETURN(res, "getnameinfo", -1);

    *serv = atoi(serv_str);

    return 0;
}


/* Fills *addr, *host and *serv with the LOCAL connection information corresponding
 * to fd. *host is the IP address as string and *serv is the service (port)
 * */
static int get_local_sock_info(int fd, struct addrinfo* addr, libpp_addr* host, uint16_t* serv)
{
    char serv_str[NI_MAXSERV];
    int res;

    // addr->ai_addr should point to a suitable sockaddr
    // addr->ai_addrlen should be initialized to its size
    res = getsockname(fd, addr->ai_addr, &addr->ai_addrlen);
    CHECK_RES_RETURN(res, "getsockname", -1);

    res = getnameinfo(addr->ai_addr, addr->ai_addrlen,
                      (char*)host, sizeof(*host),
                      serv_str, sizeof(serv_str),
                      NI_NUMERICHOST | NI_NUMERICSERV);
    if (res != 0) {
        print_message(msg_system_error, "getnameinfo for local sock: %s\n", gai_strerror(res));
        return -1;
    }

    *serv = atoi(serv_str);

    return 0;
}


int pp_write_header(int pp_version, struct connection* cnx)
{
    pp_info_t pp_info_in_v1 = {
        .transport_protocol = TRANSPORT_PROTOCOL_STREAM,
    };
    uint16_t pp1_hdr_len;
    int32_t error;

    struct sockaddr_storage ss;
    struct addrinfo addr;
    int res;

    addr.ai_addr = (struct sockaddr*)&ss;
    addr.ai_addrlen = sizeof(ss);

    res = get_peer_info(cnx->q[0].fd,
             &addr,
             &pp_info_in_v1.src_addr,
             &pp_info_in_v1.src_port);
    if (res == -1) return -1;
    pp_info_in_v1.address_family = family_to_pp(addr.ai_addr->sa_family);

    res = get_local_sock_info(cnx->q[0].fd,
             &addr,
             &pp_info_in_v1.dst_addr,
             &pp_info_in_v1.dst_port
            );
    if (res == -1) return -1;

    uint8_t *pp1_hdr = pp_create_hdr(pp_version, &pp_info_in_v1, &pp1_hdr_len, &error);

    if (!pp1_hdr) {
        print_message(msg_system_error, "pp_create_hrd:%d:%s\n", error, pp_strerror(error));
        return -1;
    }
    defer_write_before(&cnx->q[1], pp1_hdr, pp1_hdr_len);

    pp_info_clear(&pp_info_in_v1);
    free(pp1_hdr);

    return 0;
}

#endif /* HAVE_PROXYPROTOCOL */