/* $OpenBSD: canohost.c,v 1.78 2026/02/14 00:18:34 jsg Exp $ */

/*

 * Author: Tatu Ylonen <ylo@cs.hut.fi>

 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland

 *                    All rights reserved

 * Functions for returning the canonical host name of the remote site.

 *

 * As far as I am concerned, the code I have written for this software

 * can be used freely for any purpose.  Any derived versions of this

 * software must be clearly marked as such, and if the derived work is

 * incompatible with the protocol description in the RFC file, it must be

 * called by a name other than "ssh" or "Secure Shell".

 */

#include "includes.h"

#include <sys/types.h>

#include <sys/socket.h>

#include <sys/un.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <errno.h>

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <stdarg.h>

#include <unistd.h>

#include "xmalloc.h"

#include "log.h"

#include "canohost.h"

#include "misc.h"

void

ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)

{

  struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr;

  struct sockaddr_in *a4 = (struct sockaddr_in *)addr;

  struct in_addr inaddr;

  uint16_t port;

  if (addr->ss_family != AF_INET6 ||

      !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr))

    return;

  debug3("Normalising mapped IPv4 in IPv6 address");

  memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr));

  port = a6->sin6_port;

  memset(a4, 0, sizeof(*a4));

  a4->sin_family = AF_INET;

  *len = sizeof(*a4);

  memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr));

  a4->sin_port = port;

}

/*

 * Returns the local/remote IP-address/hostname of socket as a string.

 * The returned string must be freed.

 */

static char *

get_socket_address(int sock, int remote, int flags)

{

  struct sockaddr_storage addr;

  socklen_t addrlen;

  char ntop[NI_MAXHOST];

  int r;

  if (sock < 0)

    return NULL;

  /* Get IP address of client. */

  addrlen = sizeof(addr);

  memset(&addr, 0, sizeof(addr));

  if (remote) {

    if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) != 0)

      return NULL;

  } else {

    if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) != 0)

      return NULL;

  }

  /* Work around Linux IPv6 weirdness */

  if (addr.ss_family == AF_INET6) {

    addrlen = sizeof(struct sockaddr_in6);

    ipv64_normalise_mapped(&addr, &addrlen);

  }

  switch (addr.ss_family) {

  case AF_INET:

  case AF_INET6:

    /* Get the address in ascii. */

    if ((r = getnameinfo((struct sockaddr *)&addr, addrlen, ntop,

        sizeof(ntop), NULL, 0, flags)) != 0) {

      error_f("getnameinfo %d failed: %s",

          flags, ssh_gai_strerror(r));

      return NULL;

    }

    return xstrdup(ntop);

  case AF_UNIX:

    /* Get the Unix domain socket path. */

    return xstrdup(((struct sockaddr_un *)&addr)->sun_path);

  default:

    /* We can't look up remote Unix domain sockets. */

    return NULL;

  }

}

char *

get_peer_ipaddr(int sock)

{

  char *p;

  if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL)

    return p;

  return xstrdup("UNKNOWN");

}

char *

get_local_ipaddr(int sock)

{

  char *p;

  if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL)

    return p;

  return xstrdup("UNKNOWN");

}

char *

get_local_name(int fd)

{

  char *host, myname[NI_MAXHOST];

  /* Assume we were passed a socket */

  if ((host = get_socket_address(fd, 0, NI_NAMEREQD)) != NULL)

    return host;

  /* Handle the case where we were passed a pipe */

  if (gethostname(myname, sizeof(myname)) == -1) {

    verbose_f("gethostname: %s", strerror(errno));

    host = xstrdup("UNKNOWN");

  } else {

    host = xstrdup(myname);

  }

  return host;

}

/* Returns the local/remote port for the socket. */

static int

get_sock_port(int sock, int local)

{

  struct sockaddr_storage from;

  socklen_t fromlen;

  char strport[NI_MAXSERV];

  int r;

  if (sock < 0)

    return -1;

  /* Get IP address of client. */

  fromlen = sizeof(from);

  memset(&from, 0, sizeof(from));

  if (local) {

    if (getsockname(sock, (struct sockaddr *)&from, &fromlen) == -1) {

      error("getsockname failed: %.100s", strerror(errno));

      return 0;

    }

  } else {

    if (getpeername(sock, (struct sockaddr *)&from, &fromlen) == -1) {

      debug("getpeername failed: %.100s", strerror(errno));

      return -1;

    }

  }

  /* Work around Linux IPv6 weirdness */

  if (from.ss_family == AF_INET6)

    fromlen = sizeof(struct sockaddr_in6);

  /* Non-inet sockets don't have a port number. */

  if (from.ss_family != AF_INET && from.ss_family != AF_INET6)

    return 0;

  /* Return port number. */

  if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,

      strport, sizeof(strport), NI_NUMERICSERV)) != 0)

    fatal_f("getnameinfo NI_NUMERICSERV failed: %s",

        ssh_gai_strerror(r));

  return atoi(strport);

}

int

get_peer_port(int sock)

{

  return get_sock_port(sock, 0);

}

int

get_local_port(int sock)

{

  return get_sock_port(sock, 1);

}