uxnet.c

远程登陆工具软件源码 用于远程登陆unix

/*
 * Unix networking abstraction.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <sys/un.h>

#define DEFINE_PLUG_METHOD_MACROS
#include "putty.h"
#include "network.h"
#include "tree234.h"

#ifndef X11_UNIX_PATH
# define X11_UNIX_PATH "/tmp/.X11-unix/X"
#endif

#define ipv4_is_loopback(addr) (inet_netof(addr) == IN_LOOPBACKNET)

struct Socket_tag {
    struct socket_function_table *fn;
    /* the above variable absolutely *must* be the first in this structure */
    const char *error;
    int s;
    Plug plug;
    void *private_ptr;
    bufchain output_data;
    int connected;
    int writable;
    int frozen; /* this causes readability notifications to be ignored */
    int frozen_readable; /* this means we missed at least one readability
			  * notification while we were frozen */
    int localhost_only;		       /* for listening sockets */
    char oobdata[1];
    int sending_oob;
    int oobpending;		       /* is there OOB data available to read? */
    int oobinline;
    int pending_error;		       /* in case send() returns error */
    int listener;
};

/*
 * We used to typedef struct Socket_tag *Socket.
 *
 * Since we have made the networking abstraction slightly more
 * abstract, Socket no longer means a tcp socket (it could mean
 * an ssl socket).  So now we must use Actual_Socket when we know
 * we are talking about a tcp socket.
 */
typedef struct Socket_tag *Actual_Socket;

struct SockAddr_tag {
    const char *error;
    /*
     * Which address family this address belongs to. AF_INET for
     * IPv4; AF_INET6 for IPv6; AF_UNSPEC indicates that name
     * resolution has not been done and a simple host name is held
     * in this SockAddr structure.
     */
    int family;
#ifdef IPV6
    struct addrinfo *ai;	       /* Address IPv6 style. */
#else
    unsigned long address;	       /* Address IPv4 style. */
#endif
    char hostname[512];		       /* Store an unresolved host name. */
};

static tree234 *sktree;

static void uxsel_tell(Actual_Socket s);

static int cmpfortree(void *av, void *bv)
{
    Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv;
    int as = a->s, bs = b->s;
    if (as < bs)
	return -1;
    if (as > bs)
	return +1;
    return 0;
}

static int cmpforsearch(void *av, void *bv)
{
    Actual_Socket b = (Actual_Socket) bv;
    int as = *(int *)av, bs = b->s;
    if (as < bs)
	return -1;
    if (as > bs)
	return +1;
    return 0;
}

void sk_init(void)
{
    sktree = newtree234(cmpfortree);
}

void sk_cleanup(void)
{
    Actual_Socket s;
    int i;

    if (sktree) {
	for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
	    close(s->s);
	}
    }
}

const char *error_string(int error)
{
    return strerror(error);
}

SockAddr sk_namelookup(const char *host, char **canonicalname)
{
    SockAddr ret = snew(struct SockAddr_tag);
#ifdef IPV6
    struct addrinfo hints;
    int err;
#else
    unsigned long a;
    struct hostent *h = NULL;
#endif
    char realhost[8192];

    /* Clear the structure and default to IPv4. */
    memset(ret, 0, sizeof(struct SockAddr_tag));
    ret->family = 0;		       /* We set this one when we have resolved the host. */
    *realhost = '\0';
    ret->error = NULL;

#ifdef IPV6
    hints.ai_flags = AI_CANONNAME;
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = 0;
    hints.ai_protocol = 0;
    hints.ai_addrlen = 0;
    hints.ai_addr = NULL;
    hints.ai_canonname = NULL;
    hints.ai_next = NULL;
    err = getaddrinfo(host, NULL, NULL, &ret->ai);
    if (err != 0) {
	ret->error = gai_strerror(err);
	return ret;
    }
    ret->family = ret->ai->ai_family;
    *realhost = '\0';
    if (ret->ai->ai_canonname != NULL)
	strncat(realhost, ret->ai->ai_canonname, sizeof(realhost) - 1);
    else
	strncat(realhost, host, sizeof(realhost) - 1);
#else
    if ((a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
	/*
	 * Otherwise use the IPv4-only gethostbyname... (NOTE:
	 * we don't use gethostbyname as a fallback!)
	 */
	if (ret->family == 0) {
		/*debug(("Resolving \"%s\" with gethostbyname() (IPv4 only)...\n", host)); */
		if ( (h = gethostbyname(host)) )
			ret->family = AF_INET;
	}
	if (ret->family == 0) {
		ret->error = (h_errno == HOST_NOT_FOUND ||
		    h_errno == NO_DATA ||
		    h_errno == NO_ADDRESS ? "Host does not exist" :
		    h_errno == TRY_AGAIN ?
		    "Temporary name service failure" :
		    "gethostbyname: unknown error");
		return ret;
	}
	memcpy(&a, h->h_addr, sizeof(a));
	/* This way we are always sure the h->h_name is valid :) */
	strncpy(realhost, h->h_name, sizeof(realhost));
    } else {
	/*
	 * This must be a numeric IPv4 address because it caused a
	 * success return from inet_addr.
	 */
	ret->family = AF_INET;
	strncpy(realhost, host, sizeof(realhost));
    }
    ret->address = ntohl(a);
#endif
    realhost[lenof(realhost)-1] = '\0';
    *canonicalname = snewn(1+strlen(realhost), char);
    strcpy(*canonicalname, realhost);
    return ret;
}

SockAddr sk_nonamelookup(const char *host)
{
    SockAddr ret = snew(struct SockAddr_tag);
    ret->error = NULL;
    ret->family = AF_UNSPEC;
    strncpy(ret->hostname, host, lenof(ret->hostname));
    ret->hostname[lenof(ret->hostname)-1] = '\0';
    return ret;
}

void sk_getaddr(SockAddr addr, char *buf, int buflen)
{

    if (addr->family == AF_UNSPEC) {
	strncpy(buf, addr->hostname, buflen);
	buf[buflen-1] = '\0';
    } else {
#ifdef IPV6
	if (getnameinfo(addr->ai->ai_addr, addr->ai->ai_addrlen, buf, buflen,
			NULL, 0, NI_NUMERICHOST) != 0) {
	    buf[0] = '\0';
	    strncat(buf, "<unknown>", buflen - 1);
	}
#else
	struct in_addr a;
	assert(addr->family == AF_INET);
	a.s_addr = htonl(addr->address);
	strncpy(buf, inet_ntoa(a), buflen);
	buf[buflen-1] = '\0';
#endif
    }
}

int sk_hostname_is_local(char *name)
{
    return !strcmp(name, "localhost");
}

int sk_address_is_local(SockAddr addr)
{

    if (addr->family == AF_UNSPEC)
	return 0;                      /* we don't know; assume not */
    else {
#ifdef IPV6
	if (addr->family == AF_INET)
	    return ipv4_is_loopback(
		((struct sockaddr_in *)addr->ai->ai_addr)->sin_addr);
	else if (addr->family == AF_INET6)
	    return IN6_IS_ADDR_LOOPBACK(
		&((struct sockaddr_in6 *)addr->ai->ai_addr)->sin6_addr);
	else
	    return 0;
#else
	struct in_addr a;
	assert(addr->family == AF_INET);
	a.s_addr = htonl(addr->address);
	return ipv4_is_loopback(a);
#endif
    }
}

int sk_addrtype(SockAddr addr)
{
    return (addr->family == AF_INET ? ADDRTYPE_IPV4 :
#ifdef IPV6
	    addr->family == AF_INET6 ? ADDRTYPE_IPV6 :
#endif
	    ADDRTYPE_NAME);
}

void sk_addrcopy(SockAddr addr, char *buf)
{

#ifdef IPV6
    if (addr->family == AF_INET)
	memcpy(buf, &((struct sockaddr_in *)addr->ai->ai_addr)->sin_addr,
	       sizeof(struct in_addr));
    else if (addr->family == AF_INET6)
	memcpy(buf, &((struct sockaddr_in6 *)addr->ai->ai_addr)->sin6_addr,
	       sizeof(struct in6_addr));
    else
	assert(FALSE);
#else
    struct in_addr a;

    assert(addr->family == AF_INET);
    a.s_addr = htonl(addr->address);
    memcpy(buf, (char*) &a.s_addr, 4);
#endif
}

void sk_addr_free(SockAddr addr)
{

#ifdef IPV6
    if (addr->ai != NULL)
	freeaddrinfo(addr->ai);
#endif
    sfree(addr);
}

static Plug sk_tcp_plug(Socket sock, Plug p)
{
    Actual_Socket s = (Actual_Socket) sock;
    Plug ret = s->plug;
    if (p)
	s->plug = p;
    return ret;
}

static void sk_tcp_flush(Socket s)
{
    /*
     * We send data to the socket as soon as we can anyway,
     * so we don't need to do anything here.  :-)
     */
}

static void sk_tcp_close(Socket s);
static int sk_tcp_write(Socket s, const char *data, int len);
static int sk_tcp_write_oob(Socket s, const char *data, int len);
static void sk_tcp_set_private_ptr(Socket s, void *ptr);
static void *sk_tcp_get_private_ptr(Socket s);
static void sk_tcp_set_frozen(Socket s, int is_frozen);
static const char *sk_tcp_socket_error(Socket s);

static struct socket_function_table tcp_fn_table = {
    sk_tcp_plug,
    sk_tcp_close,
    sk_tcp_write,
    sk_tcp_write_oob,
    sk_tcp_flush,
    sk_tcp_set_private_ptr,
    sk_tcp_get_private_ptr,
    sk_tcp_set_frozen,
    sk_tcp_socket_error
};

Socket sk_register(OSSocket sockfd, Plug plug)
{
    Actual_Socket ret;

    /*
     * Create Socket structure.
     */
    ret = snew(struct Socket_tag);
    ret->fn = &tcp_fn_table;
    ret->error = NULL;
    ret->plug = plug;
    bufchain_init(&ret->output_data);
    ret->writable = 1;		       /* to start with */
    ret->sending_oob = 0;
    ret->frozen = 1;
    ret->frozen_readable = 0;
    ret->localhost_only = 0;	       /* unused, but best init anyway */
    ret->pending_error = 0;
    ret->oobpending = FALSE;
    ret->listener = 0;

    ret->s = sockfd;

    if (ret->s < 0) {
	ret->error = error_string(errno);
	return (Socket) ret;
    }

    ret->oobinline = 0;

    uxsel_tell(ret);
    add234(sktree, ret);

    return (Socket) ret;
}

Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
	      int nodelay, int keepalive, Plug plug)
{
    int s;
#ifdef IPV6
    struct sockaddr_in6 a6;
#endif
    struct sockaddr_in a;
    struct sockaddr_un au;
    const struct sockaddr *sa;
    int err;
    Actual_Socket ret;
    short localport;
    int fl, salen;

    /*
     * Create Socket structure.
     */
    ret = snew(struct Socket_tag);
    ret->fn = &tcp_fn_table;
    ret->error = NULL;
    ret->plug = plug;
    bufchain_init(&ret->output_data);
    ret->connected = 0;		       /* to start with */
    ret->writable = 0;		       /* to start with */
    ret->sending_oob = 0;
    ret->frozen = 0;
    ret->frozen_readable = 0;
    ret->localhost_only = 0;	       /* unused, but best init anyway */
    ret->pending_error = 0;
    ret->oobpending = FALSE;
    ret->listener = 0;

    /*
     * Open socket.
     */
    assert(addr->family != AF_UNSPEC);
    s = socket(addr->family, SOCK_STREAM, 0);
    ret->s = s;

    if (s < 0) {
	ret->error = error_string(errno);
	return (Socket) ret;
    }

    ret->oobinline = oobinline;
    if (oobinline) {
	int b = TRUE;
	setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b));
    }

    if (nodelay) {
	int b = TRUE;
	setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));
    }

    if (keepalive) {
	int b = TRUE;
	setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (void *) &b, sizeof(b));
    }

    /*
     * Bind to local address.
     */
    if (privport)
	localport = 1023;	       /* count from 1023 downwards */
    else
	localport = 0;		       /* just use port 0 (ie kernel picks) */

    /* BSD IP stacks need sockaddr_in zeroed before filling in */
    memset(&a,'\0',sizeof(struct sockaddr_in));
#ifdef IPV6
    memset(&a6,'\0',sizeof(struct sockaddr_in6));
#endif

    /* We don't try to bind to a local address for UNIX domain sockets.  (Why
     * do we bother doing the bind when localport == 0 anyway?) */
    if(addr->family != AF_UNIX) {
	/* Loop round trying to bind */
	while (1) {
	    int retcode;

#ifdef IPV6
	    if (addr->family == AF_INET6) {
		/* XXX use getaddrinfo to get a local address? */
		a6.sin6_family = AF_INET6;
		a6.sin6_addr = in6addr_any;
		a6.sin6_port = htons(localport);
		retcode = bind(s, (struct sockaddr *) &a6, sizeof(a6));
	    } else
#endif
	    {
		assert(addr->family == AF_INET);
		a.sin_family = AF_INET;
		a.sin_addr.s_addr = htonl(INADDR_ANY);
		a.sin_port = htons(localport);
		retcode = bind(s, (struct sockaddr *) &a, sizeof(a));
	    }
	    if (retcode >= 0) {
		err = 0;
		break;		       /* done */
	    } else {
		err = errno;
		if (err != EADDRINUSE) /* failed, for a bad reason */
		  break;
	    }
	    
	    if (localport == 0)
	      break;		       /* we're only looping once */
	    localport--;
	    if (localport == 0)
	      break;		       /* we might have got to the end */
	}
	
	if (err) {
	    ret->error = error_string(err);
	    return (Socket) ret;
	}
    }

    /*
     * Connect to remote address.
     */
    switch(addr->family) {
#ifdef IPV6
      case AF_INET:
	/* XXX would be better to have got getaddrinfo() to fill in the port. */
	((struct sockaddr_in *)addr->ai->ai_addr)->sin_port =
	    htons(port);
	sa = (const struct sockaddr *)addr->ai->ai_addr;
	salen = addr->ai->ai_addrlen;
	break;
      case AF_INET6:
	((struct sockaddr_in *)addr->ai->ai_addr)->sin_port =
	    htons(port);
	sa = (const struct sockaddr *)addr->ai->ai_addr;
	salen = addr->ai->ai_addrlen;
	break;
#else
      case AF_INET:
	a.sin_family = AF_INET;
	a.sin_addr.s_addr = htonl(addr->address);
	a.sin_port = htons((short) port);
	sa = (const struct sockaddr *)&a;
	salen = sizeof a;
	break;
#endif
      case AF_UNIX:
	assert(port == 0);	/* to catch confused people */
	assert(strlen(addr->hostname) < sizeof au.sun_path);
	memset(&au, 0, sizeof au);
	au.sun_family = AF_UNIX;
	strcpy(au.sun_path, addr->hostname);
	sa = (const struct sockaddr *)&au;
	salen = sizeof au;
	break;

      default:
	assert(0 && "unknown address family");
    }

    fl = fcntl(s, F_GETFL);
    if (fl != -1)
	fcntl(s, F_SETFL, fl | O_NONBLOCK);

    if ((connect(s, sa, salen)) < 0) {
	if ( errno != EINPROGRESS ) {
	    ret->error = error_string(errno);
	    return (Socket) ret;
	}
    } else {
	/*
	 * If we _don't_ get EWOULDBLOCK, the connect has completed
	 * and we should set the socket as connected and writable.
	 */
	ret->connected = 1;
	ret->writable = 1;
    }

    uxsel_tell(ret);
    add234(sktree, ret);

    sk_addr_free(addr);