tun-bsd.c

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/*
 * tun-bsd.c
 *
 * Copyright (c) 2001 Dug Song <dugsong@monkey.org>
 *
 * $Id: tun-bsd.c,v 1.3 2005/02/10 23:50:04 dugsong Exp $
 */

#include "config.h"

#include <sys/socket.h>
#include <sys/uio.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "dnet.h"

struct tun {
        int               fd;
        intf_t           *intf;
        struct intf_entry save;
};

#define MAX_DEVS        16      /* XXX - max number of tunnel devices */

tun_t *
tun_open(struct addr *src, struct addr *dst, int mtu)
{
        struct intf_entry ifent;
        tun_t *tun;
        char dev[128];
        int i;

        if (src->addr_type != ADDR_TYPE_IP || dst->addr_type != ADDR_TYPE_IP ||
            src->addr_bits != IP_ADDR_BITS || dst->addr_bits != IP_ADDR_BITS) {
                errno = EINVAL;
                return (NULL);
        }
        if ((tun = calloc(1, sizeof(*tun))) == NULL)
                return (NULL);

        if ((tun->intf = intf_open()) == NULL)
                return (tun_close(tun));

        memset(&ifent, 0, sizeof(ifent));
        ifent.intf_len = sizeof(ifent);
        
        for (i = 0; i < MAX_DEVS; i++) {
                snprintf(dev, sizeof(dev), "/dev/tun%d", i);
                strlcpy(ifent.intf_name, dev + 5, sizeof(ifent.intf_name));
                tun->save = ifent;
                
                if ((tun->fd = open(dev, O_RDWR, 0)) != -1 &&
                    intf_get(tun->intf, &tun->save) == 0) {
                        route_t *r;
                        struct route_entry entry;
                        
                        ifent.intf_flags = INTF_FLAG_UP|INTF_FLAG_POINTOPOINT;
                        ifent.intf_addr = *src;
                        ifent.intf_dst_addr = *dst;     
                        ifent.intf_mtu = mtu;
                        
                        if (intf_set(tun->intf, &ifent) < 0)
                                tun = tun_close(tun);

                        /* XXX - try to ensure our route got set */
                        if ((r = route_open()) != NULL) {
                                entry.route_dst = *dst;
                                entry.route_gw = *src;
                                route_add(r, &entry);
                                route_close(r);
                        }
                        break;
                }
        }
        if (i == MAX_DEVS)
                tun = tun_close(tun);
        return (tun);
}

const char *
tun_name(tun_t *tun)
{
        return (tun->save.intf_name);
}

int
tun_fileno(tun_t *tun)
{
        return (tun->fd);
}

ssize_t
tun_send(tun_t *tun, const void *buf, size_t size)
{
#ifdef __OpenBSD__
        struct iovec iov[2];
        uint32_t af = htonl(AF_INET);

        iov[0].iov_base = &af;
        iov[0].iov_len = sizeof(af);
        iov[1].iov_base = (void *)buf;
        iov[1].iov_len = size;
        
        return (writev(tun->fd, iov, 2));
#else
        return (write(tun->fd, buf, size));
#endif
}

ssize_t
tun_recv(tun_t *tun, void *buf, size_t size)
{
#ifdef __OpenBSD__
        struct iovec iov[2];
        uint32_t af;
        
        iov[0].iov_base = &af;
        iov[0].iov_len = sizeof(af);
        iov[1].iov_base = (void *)buf;
        iov[1].iov_len = size;
        
        return (readv(tun->fd, iov, 2) - sizeof(af));
#else
        return (read(tun->fd, buf, size));
#endif
}

tun_t *
tun_close(tun_t *tun)
{
        if (tun->fd > 0)
                close(tun->fd);
        if (tun->intf != NULL) {
                /* Restore interface configuration on close. */
                intf_set(tun->intf, &tun->save);
                intf_close(tun->intf);
        }
        free(tun);
        return (NULL);
}

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