tap cleanup, more *BSD support.

This commit is contained in:
Kelvin Sherlock 2018-12-31 20:49:39 -05:00
parent aaeda41baf
commit fae38450e9

View File

@ -1,6 +1,39 @@
/* tun/tap support */
/* for Linux, *BSD */
/*
* tap is a virtual ethernet devices.
* open the device, configure, and read/write ethernet frames.
*
* Linux setup: (from Network Programmability and Automation, Appendix A)
*
* Notes:
* - this assumes eth0 is your main interface device
* - may need to install the iproute/iproute2 package (ip command)
* - do this stuff as root.
*
* 1. create a tap interface
* $ ip tuntap add tap65816 mode tap user YOUR_USER_NAME
* $ ip link set tap65816 up
*
* 2. create a network bridge
* $ ip link add name br0 type bridge
* $ ip link set br0 up
*
* 3. bridge the physical network and virtual network.
* $ ip link set eth0 master br0
* $ ip link set tap65816 master br0
*
* 4. remove ip address from physical device (This will kill networking)
* ip address flush dev eth0
*
* 5. and add the ip address to the bridge
* dhclient br0 # if using dhcp
* ip address add 192.168.1.1/24 dev eth0 # if using static ip address.
*/
#define _GNU_SOURCE
#include <errno.h>
@ -25,15 +58,15 @@
#include "rawnetsupp.h"
#if defined(__linux__)
const char *default_interface_name = "/dev/net/tun";
#define TAP_DEVICE "/dev/net/tun"
#endif
#if defined(__FreeBSD__)
const char *default_interface_name = "/dev/tap";
#define TAP_DEVICE "/dev/tap"
#endif
static int interface_fd = -1;
static char *interface_dev = NULL;
int rawnet_arch_init(void) {
interface_fd = -1;
@ -48,35 +81,25 @@ void rawnet_arch_post_reset(void) {
}
/* interface name may be a full path (/dev/tap0) or relative (tap0) */
#if defined(__linux__)
/* interface name. default is tap65816. */
int rawnet_arch_activate(const char *interface_name) {
struct ifreq ifr;
int ok;
char *tmp = NULL;
int one = 1;
int fd;
if (!interface_name || !*interface_name) {
interface_name = default_interface_name;
}
if (interface_name[0] != '/') {
ok = asprintf(&tmp, "/dev/%s", interface_name);
if (ok < 0) {
perror("rawnet_arch_activate: asprintf");
return 0;
}
interface_name = tmp;
interface_name = "tap65816";
}
fd = open(interface_name, O_RDWR);
fd = open(TAP_DEVICE, O_RDWR);
if (fd < 0) {
fprintf(stderr, "rawnet_arch_activate: open(%s): %s\n", interface_name, strerror(errno));
free(tmp);
fprintf(stderr, "rawnet_arch_activate: open(%s): %s\n", TAP_DEVICE, strerror(errno));
return 0;
}
free(tmp);
ok = ioctl(fd, FIONBIO, &one);
if (ok < 0) {
@ -85,8 +108,8 @@ int rawnet_arch_activate(const char *interface_name) {
return 0;
}
#if defined(__linux__)
memset(&ifr, 0, sizeof(ifr));
strcpy(&if.ifr_name, interface_name);
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
ok = ioctl(fd, TUNSETIFF, (void *) &ifr);
if (ok < 0) {
@ -94,15 +117,60 @@ int rawnet_arch_activate(const char *interface_name) {
close(fd);
return 0;
}
#endif
interface_dev = strdup(interface_name);
interface_fd = fd;
return 1;
}
#endif
#if defined(__FreeBSD__)
/* man tap(4) */
/* interface name. default is tap65816. */
int rawnet_arch_activate(const char *interface_name) {
struct ifreq ifr;
int ok;
int one = 1;
int fd;
char *path[64];
if (!interface_name || !*interface_name) {
interface_name = "tap65816";
}
ok = snprintf(path, sizeof(path), "/dev/%s", interface_name);
if (ok >= sizeof(path)) return 0;
fd = open(path, O_RDWR);
if (fd < 0) {
fprintf(stderr, "rawnet_arch_activate: open(%s): %s\n", path, strerror(errno));
return 0;
}
ok = ioctl(fd, FIONBIO, &one);
if (ok < 0) {
perror("ioctl(FIONBIO");
close(fd);
return 0;
}
interface_dev = strdup(interface_name);
interface_fd = fd;
return 1;
}
#endif
void rawnet_arch_deactivate(void) {
if (interface_fd >= 0)
close(interface_fd);
free(interface_dev);
interface_dev = NULL;
interface_fd = -1;
}
@ -177,6 +245,9 @@ int rawnet_arch_enumadapter_open(void) {
devices = (char **)malloc(sizeof(char *) * capacity);
if (!devices) return 0;
#if defined(__linux__)
dp = opendir("/sys/class/net/");
if (!dp) goto fail;
@ -196,7 +267,7 @@ int rawnet_arch_enumadapter_open(void) {
if (cp) {
/* expect 0x1002 */
int flags = strtol(cp, (char **)NULL, 16);
if (flags == IFF_TAP | IFF_NO_PI) {
if ((flags & TUN_TYPE_MASK) == IFF_TAP) {
devices[count++] = strdup(d->d_name);
if (count == capacity) {
@ -212,6 +283,32 @@ int rawnet_arch_enumadapter_open(void) {
}
closedir(dp);
#endif
#if defined(__FreeBSD__)
/* dev/tapxxxx */
dp = opendir("/dev/");
if (!dp) goto fail;
for(;;) {
struct dirent *d = readdir(dp);
if (!d) break;
if (d->d_name[0] == '.') continue;
if (strncmp(d->d_name, "tap", 3) == 0 && isdigit(d->d_name[3])) {
devices[count++] = strdup(d->d_name);
if (count == capacity) {
char **tmp;
capacity *= 2;
tmp = (char **)realloc(devices, sizeof(char *) * capacity);
if (tmp) devices = tmp;
else break; /* no mem? */
}
}
}
closedir(dp);
#endif
/* sort them ... */
qsort(devices, count, sizeof(char *), cmp);
@ -253,16 +350,17 @@ int rawnet_arch_enumadapter(char **ppname, char **ppdescription) {
char *rawnet_arch_get_standard_interface(void) {
return lib_stralloc(default_interface_name);
return lib_stralloc("tap65816");
}
int rawnet_arch_get_mtu(void) {
if (interface_fd < 0) return -1;
#if defined(__linux__)
/* n.b. linux tap driver doesn't actually support SIOCGIFMTU */
struct ifreq ifr;
if (ioctl(interface_fd, TUNGETIFF, (void *) &ifr) < 0) return -1; /* ? */
memset(&ifr, 0, sizeof(ifr));
if (ioctl(interface_fd, SIOCGIFMTU, (void *) &ifr) < 0) return -1; /* ? */
return ifr.ifr_mtu;
#endif
@ -282,6 +380,7 @@ int rawnet_arch_get_mac(uint8_t mac[6]) {
#if defined(__linux__)
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
if (ioctl(interface_fd, SIOCGIFHWADDR, (void *)&ifr) < 0) return -1;
memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
return 0;