/* $OpenBSD: canohost.c,v 1.77 2023/03/31 04:42:29 dtucker 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 "packet.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;
        u_int16_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);
}