socket_wrapper.c

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/*
 * Copyright (C) Jelmer Vernooij 2005,2008 <[e-mail]>
 * Copyright (C) Stefan Metzmacher 2006 <[e-mail]>
 *
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the author nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

/*
   Socket wrapper library. Passes all socket communication over
   unix domain sockets if the environment variable SOCKET_WRAPPER_DIR
   is set.
*/

#ifdef _SAMBA_BUILD_

#define SOCKET_WRAPPER_NOT_REPLACE
#include "lib/replace/replace.h"
#include "system/network.h"
#include "system/filesys.h"
#include "system/time.h"

#else /* _SAMBA_BUILD_ */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/filio.h>
#include <errno.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>

#endif

#ifndef _PUBLIC_
#define _PUBLIC_
#endif

#define SWRAP_DLIST_ADD(list,item) do { \
	if (!(list)) { \
		(item)->prev	= NULL; \
		(item)->next	= NULL; \
		(list)		= (item); \
	} else { \
		(item)->prev	= NULL; \
		(item)->next	= (list); \
		(list)->prev	= (item); \
		(list)		= (item); \
	} \
} while (0)

#define SWRAP_DLIST_REMOVE(list,item) do { \
	if ((list) == (item)) { \
		(list)		= (item)->next; \
		if (list) { \
			(list)->prev	= NULL; \
		} \
	} else { \
		if ((item)->prev) { \
			(item)->prev->next	= (item)->next; \
		} \
		if ((item)->next) { \
			(item)->next->prev	= (item)->prev; \
		} \
	} \
	(item)->prev	= NULL; \
	(item)->next	= NULL; \
} while (0)

/* LD_PRELOAD doesn't work yet, so REWRITE_CALLS is all we support
 * for now */
#define REWRITE_CALLS 

#ifdef REWRITE_CALLS
#define real_accept accept
#define real_connect connect
#define real_bind bind
#define real_listen listen
#define real_getpeername getpeername
#define real_getsockname getsockname
#define real_getsockopt getsockopt
#define real_setsockopt setsockopt
#define real_recvfrom recvfrom
#define real_sendto sendto
#define real_ioctl ioctl
#define real_recv recv
#define real_send send
#define real_socket socket
#define real_close close
#endif

#ifdef HAVE_GETTIMEOFDAY_TZ
#define swrapGetTimeOfDay(tval) gettimeofday(tval,NULL)
#else
#define swrapGetTimeOfDay(tval)	gettimeofday(tval)
#endif

/* we need to use a very terse format here as IRIX 6.4 silently
   truncates names to 16 chars, so if we use a longer name then we
   can't tell which port a packet came from with recvfrom() 
   
   with this format we have 8 chars left for the directory name
*/
#define SOCKET_FORMAT "%c%02X%04X"
#define SOCKET_TYPE_CHAR_TCP		'T'
#define SOCKET_TYPE_CHAR_UDP		'U'
#define SOCKET_TYPE_CHAR_TCP_V6		'X'
#define SOCKET_TYPE_CHAR_UDP_V6		'Y'

#define MAX_WRAPPED_INTERFACES 16

#define SW_IPV6_ADDRESS 1

static struct sockaddr *sockaddr_dup(const void *data, socklen_t len)
{
	struct sockaddr *ret = (struct sockaddr *)malloc(len);
	memcpy(ret, data, len);
	return ret;
}

static void set_port(int family, int prt, struct sockaddr *addr)
{
	switch (family) {
	case AF_INET:
		((struct sockaddr_in *)addr)->sin_port = htons(prt);
		break;
#ifdef HAVE_IPV6
	case AF_INET6:
		((struct sockaddr_in6 *)addr)->sin6_port = htons(prt);
		break;
#endif
	}
}

static size_t socket_length(int family)
{
	switch (family) {
	case AF_INET:
		return sizeof(struct sockaddr_in);
#ifdef HAVE_IPV6
	case AF_INET6:
		return sizeof(struct sockaddr_in6);
#endif
	}
	return 0;
}



struct socket_info
{
	int fd;

	int family;
	int type;
	int protocol;
	int bound;
	int bcast;
	int is_server;

	char *path;
	char *tmp_path;

	struct sockaddr *myname;
	socklen_t myname_len;

	struct sockaddr *peername;
	socklen_t peername_len;

	struct {
		unsigned long pck_snd;
		unsigned long pck_rcv;
	} io;

	struct socket_info *prev, *next;
};

static struct socket_info *sockets;

const char *socket_wrapper_dir(void)
{
	const char *s = getenv("SOCKET_WRAPPER_DIR");
	if (s == NULL) {
		return NULL;
	}
	if (strncmp(s, "./", 2) == 0) {
		s += 2;
	}
	return s;
}

unsigned int socket_wrapper_default_iface(void)
{
	const char *s = getenv("SOCKET_WRAPPER_DEFAULT_IFACE");
	if (s) {
		unsigned int iface;
		if (sscanf(s, "%u", &iface) == 1) {
			if (iface >= 1 && iface <= MAX_WRAPPED_INTERFACES) {
				return iface;
			}
		}
	}

	return 1;/* 127.0.0.1 */
}

static int convert_un_in(const struct sockaddr_un *un, struct sockaddr *in, socklen_t *len)
{
	unsigned int iface;
	unsigned int prt;
	const char *p;
	char type;

	p = strrchr(un->sun_path, '/');
	if (p) p++; else p = un->sun_path;

	if (sscanf(p, SOCKET_FORMAT, &type, &iface, &prt) != 3) {
		errno = EINVAL;
		return -1;
	}

	if (iface == 0 || iface > MAX_WRAPPED_INTERFACES) {
		errno = EINVAL;
		return -1;
	}

	if (prt > 0xFFFF) {
		errno = EINVAL;
		return -1;
	}

	switch(type) {
	case SOCKET_TYPE_CHAR_TCP:
	case SOCKET_TYPE_CHAR_UDP: {
		struct sockaddr_in *in2 = (struct sockaddr_in *)in;
		
		if ((*len) < sizeof(*in2)) {
		    errno = EINVAL;
		    return -1;
		}

		memset(in2, 0, sizeof(*in2));
		in2->sin_family = AF_INET;
		in2->sin_addr.s_addr = htonl((127<<24) | iface);
		in2->sin_port = htons(prt);

		*len = sizeof(*in2);
		break;
	}
#ifdef HAVE_IPV6
	case SOCKET_TYPE_CHAR_TCP_V6:
	case SOCKET_TYPE_CHAR_UDP_V6: {
		struct sockaddr_in6 *in2 = (struct sockaddr_in6 *)in;
		
		if ((*len) < sizeof(*in2)) {
			errno = EINVAL;
			return -1;
		}

		memset(in2, 0, sizeof(*in2));
		in2->sin6_family = AF_INET6;
		in2->sin6_addr.s6_addr[0] = SW_IPV6_ADDRESS;
		in2->sin6_port = htons(prt);

		*len = sizeof(*in2);
		break;
	}
#endif
	default:
		errno = EINVAL;
		return -1;
	}

	return 0;
}

static int convert_in_un_remote(struct socket_info *si, const struct sockaddr *inaddr, struct sockaddr_un *un,
				int *bcast)
{
	char type = '\0';
	unsigned int prt;
	unsigned int iface;
	int is_bcast = 0;

	if (bcast) *bcast = 0;

	switch (si->family) {
	case AF_INET: {
		const struct sockaddr_in *in = 
		    (const struct sockaddr_in *)inaddr;
		unsigned int addr = ntohl(in->sin_addr.s_addr);
		char u_type = '\0';
		char b_type = '\0';
		char a_type = '\0';

		switch (si->type) {
		case SOCK_STREAM:
			u_type = SOCKET_TYPE_CHAR_TCP;
			break;
		case SOCK_DGRAM:
			u_type = SOCKET_TYPE_CHAR_UDP;
			a_type = SOCKET_TYPE_CHAR_UDP;
			b_type = SOCKET_TYPE_CHAR_UDP;
			break;
		}

		prt = ntohs(in->sin_port);
		if (a_type && addr == 0xFFFFFFFF) {
			/* 255.255.255.255 only udp */
			is_bcast = 2;
			type = a_type;
			iface = socket_wrapper_default_iface();
		} else if (b_type && addr == 0x7FFFFFFF) {
			/* 127.255.255.255 only udp */
			is_bcast = 1;
			type = b_type;
			iface = socket_wrapper_default_iface();
		} else if ((addr & 0xFFFFFF00) == 0x7F000000) {
			/* 127.0.0.X */
			is_bcast = 0;
			type = u_type;
			iface = (addr & 0x000000FF);
		} else {
			errno = ENETUNREACH;
			return -1;
		}
		if (bcast) *bcast = is_bcast;
		break;
	}
#ifdef HAVE_IPV6
	case AF_INET6: {
		const struct sockaddr_in6 *in = 
		    (const struct sockaddr_in6 *)inaddr;

		switch (si->type) {
		case SOCK_STREAM:
			type = SOCKET_TYPE_CHAR_TCP_V6;
			break;
		case SOCK_DGRAM:
			type = SOCKET_TYPE_CHAR_UDP_V6;
			break;
		}

		/* XXX no multicast/broadcast */

		prt = ntohs(in->sin6_port);
		iface = SW_IPV6_ADDRESS;
		
		break;
	}
#endif
	default:
		errno = ENETUNREACH;
		return -1;
	}

	if (prt == 0) {
		errno = EINVAL;
		return -1;
	}

	if (is_bcast) {
		snprintf(un->sun_path, sizeof(un->sun_path), "%s/EINVAL", 
			 socket_wrapper_dir());
		/* the caller need to do more processing */
		return 0;
	}

	snprintf(un->sun_path, sizeof(un->sun_path), "%s/"SOCKET_FORMAT, 
		 socket_wrapper_dir(), type, iface, prt);

	return 0;
}

static int convert_in_un_alloc(struct socket_info *si, const struct sockaddr *inaddr, struct sockaddr_un *un,
			       int *bcast)
{
	char type = '\0';
	unsigned int prt;
	unsigned int iface;
	struct stat st;
	int is_bcast = 0;

	if (bcast) *bcast = 0;

	switch (si->family) {
	case AF_INET: {
		const struct sockaddr_in *in = 
		    (const struct sockaddr_in *)inaddr;
		unsigned int addr = ntohl(in->sin_addr.s_addr);
		char u_type = '\0';
		char d_type = '\0';
		char b_type = '\0';
		char a_type = '\0';

		prt = ntohs(in->sin_port);

		switch (si->type) {
		case SOCK_STREAM:
			u_type = SOCKET_TYPE_CHAR_TCP;
			d_type = SOCKET_TYPE_CHAR_TCP;
			break;
		case SOCK_DGRAM:
			u_type = SOCKET_TYPE_CHAR_UDP;
			d_type = SOCKET_TYPE_CHAR_UDP;
			a_type = SOCKET_TYPE_CHAR_UDP;
			b_type = SOCKET_TYPE_CHAR_UDP;
			break;
		}

		if (addr == 0) {
			/* 0.0.0.0 */
		 	is_bcast = 0;
			type = d_type;
			iface = socket_wrapper_default_iface();
		} else if (a_type && addr == 0xFFFFFFFF) {
			/* 255.255.255.255 only udp */
			is_bcast = 2;
			type = a_type;
			iface = socket_wrapper_default_iface();
		} else if (b_type && addr == 0x7FFFFFFF) {
			/* 127.255.255.255 only udp */
			is_bcast = 1;
			type = b_type;
			iface = socket_wrapper_default_iface();
		} else if ((addr & 0xFFFFFF00) == 0x7F000000) {
			/* 127.0.0.X */
			is_bcast = 0;
			type = u_type;
			iface = (addr & 0x000000FF);
		} else {
			errno = EADDRNOTAVAIL;
			return -1;
		}
		break;
	}
#ifdef HAVE_IPV6
	case AF_INET6: {
		const struct sockaddr_in6 *in = 
		    (const struct sockaddr_in6 *)inaddr;

		switch (si->type) {
		case SOCK_STREAM:
			type = SOCKET_TYPE_CHAR_TCP_V6;
			break;
		case SOCK_DGRAM:
			type = SOCKET_TYPE_CHAR_UDP_V6;
			break;
		}

		/* XXX no multicast/broadcast */

		prt = ntohs(in->sin6_port);
		iface = SW_IPV6_ADDRESS;
		
		break;
	}
#endif
	default:
		errno = ENETUNREACH;
		return -1;
	}


	if (bcast) *bcast = is_bcast;

	if (prt == 0) {
		/* handle auto-allocation of ephemeral ports */
		for (prt = 5001; prt < 10000; prt++) {
			snprintf(un->sun_path, sizeof(un->sun_path), "%s/"SOCKET_FORMAT, 
				 socket_wrapper_dir(), type, iface, prt);
			if (stat(un->sun_path, &st) == 0) continue;

			set_port(si->family, prt, si->myname);
			break;
		}
		if (prt == 10000) {
			errno = ENFILE;
			return -1;
		}
	}

	snprintf(un->sun_path, sizeof(un->sun_path), "%s/"SOCKET_FORMAT, 
		 socket_wrapper_dir(), type, iface, prt);
	return 0;
}

static struct socket_info *find_socket_info(int fd)
{
	struct socket_info *i;
	for (i = sockets; i; i = i->next) {
		if (i->fd == fd) 
			return i;
	}

	return NULL;
}

static int sockaddr_convert_to_un(struct socket_info *si, const struct sockaddr *in_addr, socklen_t in_len, 
				  struct sockaddr_un *out_addr, int alloc_sock, int *bcast)
{
	if (!out_addr)
		return 0;

	out_addr->sun_family = AF_UNIX;

	switch (in_addr->sa_family) {
	case AF_INET:
#ifdef HAVE_IPV6
	case AF_INET6:
#endif
		switch (si->type) {
		case SOCK_STREAM:
		case SOCK_DGRAM:
			break;
		default:
			errno = ESOCKTNOSUPPORT;
			return -1;
		}
		if (alloc_sock) {
			return convert_in_un_alloc(si, in_addr, out_addr, bcast);
		} else {
			return convert_in_un_remote(si, in_addr, out_addr, bcast);
		}
	default:
		break;
	}
	
	errno = EAFNOSUPPORT;
	return -1;
}

static int sockaddr_convert_from_un(const struct socket_info *si, 
				    const struct sockaddr_un *in_addr, 
				    socklen_t un_addrlen,
				    int family,
				    struct sockaddr *out_addr,
				    socklen_t *out_addrlen)
{
	if (out_addr == NULL || out_addrlen == NULL) 
		return 0;

	if (un_addrlen == 0) {
		*out_addrlen = 0;
		return 0;
	}

	switch (family) {
	case AF_INET:
#ifdef HAVE_IPV6
	case AF_INET6:
#endif
		switch (si->type) {
		case SOCK_STREAM:
		case SOCK_DGRAM:
			break;
		default:
			errno = ESOCKTNOSUPPORT;
			return -1;
		}
		return convert_un_in(in_addr, out_addr, out_addrlen);
	default:
		break;
	}

	errno = EAFNOSUPPORT;
	return -1;
}

enum swrap_packet_type {
	SWRAP_CONNECT_SEND,
	SWRAP_CONNECT_UNREACH,
	SWRAP_CONNECT_RECV,
	SWRAP_CONNECT_ACK,
	SWRAP_ACCEPT_SEND,
	SWRAP_ACCEPT_RECV,