Porting PicoTCP WIP

kernel/picotcp/modules/pico_dev_tap.c

@@ -0,0 +1,230 @@
+/*********************************************************************
+   PicoTCP. Copyright (c) 2012-2017 Altran Intelligent Systems. Some rights reserved.
+   See COPYING, LICENSE.GPLv2 and LICENSE.GPLv3 for usage.
+
+   Authors: Daniele Lacamera
+ *********************************************************************/
+
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <signal.h>
+#include "pico_device.h"
+#include "pico_dev_tap.h"
+#include "pico_stack.h"
+
+#ifndef __FreeBSD__
+#include <linux/if_tun.h>
+#endif
+
+#include <sys/poll.h>
+
+struct pico_device_tap {
+    struct pico_device dev;
+    int fd;
+};
+
+#define TUN_MTU 2048
+
+/* We only support one global link state - we only have two USR signals, we */
+/* can't spread these out over an arbitrary amount of devices. When you unplug */
+/* one tap, you unplug all of them. */
+
+static int tapdev_link_state = 0;
+
+static void sig_handler(int signo)
+{
+    if (signo == SIGUSR1) {
+        tapdev_link_state = 0;
+    }
+
+    if (signo == SIGUSR2) {
+        tapdev_link_state = 1;
+    }
+}
+
+static int tap_link_state(__attribute__((unused)) struct pico_device *self)
+{
+    return tapdev_link_state;
+}
+
+
+static int pico_tap_send(struct pico_device *dev, void *buf, int len)
+{
+    struct pico_device_tap *tap = (struct pico_device_tap *) dev;
+    return (int)write(tap->fd, buf, (uint32_t)len);
+}
+
+static int pico_tap_poll(struct pico_device *dev, int loop_score)
+{
+    struct pico_device_tap *tap = (struct pico_device_tap *) dev;
+    struct pollfd pfd;
+    unsigned char buf[TUN_MTU];
+    int len;
+    pfd.fd = tap->fd;
+    pfd.events = POLLIN;
+    do  {
+        if (poll(&pfd, 1, 0) <= 0) {
+            return loop_score;
+        }
+
+        len = (int)read(tap->fd, buf, TUN_MTU);
+        if (len > 0) {
+            loop_score--;
+            pico_stack_recv(dev, buf, (uint32_t)len);
+        }
+    } while(loop_score > 0);
+    return 0;
+}
+
+/* Public interface: create/destroy. */
+
+void pico_tap_destroy(struct pico_device *dev)
+{
+    struct pico_device_tap *tap = (struct pico_device_tap *) dev;
+    if(tap->fd > 0) {
+        close(tap->fd);
+    }
+}
+
+#ifndef __FreeBSD__
+static int tap_open(char *name)
+{
+    struct ifreq ifr;
+    int tap_fd;
+    if((tap_fd = open("/dev/net/tun", O_RDWR)) < 0) {
+        return -1;
+    }
+
+    memset(&ifr, 0, sizeof(ifr));
+    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+    strncpy(ifr.ifr_name, name, IFNAMSIZ);
+    if(ioctl(tap_fd, TUNSETIFF, &ifr) < 0) {
+        return -1;
+    }
+
+    return tap_fd;
+}
+#else
+static int tap_open(char *name)
+{
+    int tap_fd;
+    (void)name;
+    tap_fd = open("/dev/tap0", O_RDWR);
+    return tap_fd;
+}
+#endif
+
+
+#ifndef __FreeBSD__
+static int tap_get_mac(char *name, uint8_t *mac)
+{
+    int sck;
+    struct ifreq eth;
+    int retval = -1;
+
+    sck = socket(AF_INET, SOCK_DGRAM, 0);
+    if(sck < 0) {
+        return retval;
+    }
+
+    memset(&eth, 0, sizeof(struct ifreq));
+    strcpy(eth.ifr_name, name);
+    /* call the IOCTL */
+    if (ioctl(sck, SIOCGIFHWADDR, &eth) < 0) {
+        perror("ioctl(SIOCGIFHWADDR)");
+        return -1;
+    }
+
+    memcpy (mac, &eth.ifr_hwaddr.sa_data, 6);
+    close(sck);
+    return 0;
+
+}
+#else
+#include <net/if_dl.h>
+#include <ifaddrs.h>
+#include <net/if_types.h>
+static int tap_get_mac(char *name, uint8_t *mac)
+{
+    struct sockaddr_dl *sdl;
+    struct ifaddrs *ifap, *root;
+    if (getifaddrs(&ifap) != 0)
+        return -1;
+
+    root = ifap;
+    while(ifap) {
+        if (strcmp(name, ifap->ifa_name) == 0) {
+            sdl = (struct sockaddr_dl *) ifap->ifa_addr;
+        }
+
+        if (sdl->sdl_type == IFT_ETHER) {
+            memcpy(mac, LLADDR(sdl), 6);
+            freeifaddrs(root);
+            return 0;
+        }
+
+        ifap = ifap->ifa_next;
+    }
+    freeifaddrs(root);
+    return 0;
+}
+#endif
+
+struct pico_device *pico_tap_create(char *name)
+{
+    struct pico_device_tap *tap = PICO_ZALLOC(sizeof(struct pico_device_tap));
+    uint8_t mac[6] = {};
+    struct sigaction sa;
+
+    if (!tap) {
+        return NULL;
+    }
+
+    sa.sa_flags = 0;
+    sigemptyset(&sa.sa_mask);
+    sa.sa_handler = sig_handler;
+
+    if ((sigaction(SIGUSR1, &sa, NULL) == 0) &&
+        (sigaction(SIGUSR2, &sa, NULL) == 0)) {
+        tap->dev.link_state = &tap_link_state;
+    }
+
+    tap->dev.overhead = 0;
+    tap->fd = tap_open(name);
+    if (tap->fd < 0) {
+        dbg("Tap creation failed.\n");
+        pico_tap_destroy((struct pico_device *)tap);
+        return NULL;
+    }
+
+    /* Host's mac address is generated * by the host kernel and is
+     * retrieved via tap_get_mac().
+     */
+    if (tap_get_mac(name, mac) < 0) {
+        dbg("Tap mac query failed.\n");
+        pico_tap_destroy((struct pico_device *)tap);
+        return NULL;
+    }
+
+    /* To act as a second endpoint in the same subnet, the picoTCP
+     * app using the tap device must have a different mac address.
+     * For simplicity, we just add 1 to the last byte of the linux
+     * endpoint so the two addresses are consecutive.
+     */
+    mac[5]++;
+
+    if( 0 != pico_device_init((struct pico_device *)tap, name, mac)) {
+        dbg("Tap init failed.\n");
+        pico_tap_destroy((struct pico_device *)tap);
+        return NULL;
+    }
+
+    tap->dev.send = pico_tap_send;
+    tap->dev.poll = pico_tap_poll;
+    tap->dev.destroy = pico_tap_destroy;
+    dbg("Device %s created.\n", tap->dev.name);
+    return (struct pico_device *)tap;
+}
+