Add tun.[ch]

src/tun.c

@@ -0,0 +1,202 @@
+#include "common-static.h"
+#include "tun.h"
+
+#include <stdio.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+
+#ifdef __linux__
+# include <linux/if.h>
+# include <linux/if_tun.h>
+#endif
+
+#ifdef __APPLE__
+# include <sys/sys_domain.h>
+# include <sys/kern_control.h>
+# include <net/if_utun.h>
+#endif
+
+#if defined(__APPLE__) || defined(__OpenBSD__)
+# define GT_BSD_TUN 1
+#endif
+
+#ifdef __linux__
+int tun_create (char *name, int multiqueue)
+{
+    int fd = open("/dev/net/tun", O_RDWR);
+
+    if (fd<0) {
+        perror("open /dev/net/tun");
+        return -1;
+    }
+
+    struct ifreq ifr = {
+        .ifr_flags = IFF_TUN|IFF_NO_PI,
+    };
+
+    if (multiqueue) {
+#ifdef IFF_MULTI_QUEUE
+        ifr.ifr_flags |= IFF_MULTI_QUEUE;
+#else
+        gt_not_available("IFF_MULTI_QUEUE");
+#endif
+    }
+
+    str_cpy(ifr.ifr_name, name, IFNAMSIZ-1);
+
+    int ret = ioctl(fd, TUNSETIFF, &ifr);
+
+    if (ret<0) {
+        perror("ioctl TUNSETIFF");
+        return -1;
+    }
+
+    printf("tun name: %s\n", ifr.ifr_name);
+
+    return fd;
+}
+#elif defined(__APPLE__)
+int tun_create (_unused_ char *name, _unused_ int mq)
+{
+    struct ctl_info ctlInfo;
+    struct sockaddr_ctl sc;
+    int fd;
+
+    for (unsigned dev_id = 0U; dev_id<32U; dev_id++) {
+        byte_set(&ctlInfo, 0, sizeof(ctlInfo));
+        str_cpy(ctlInfo.ctl_name, UTUN_CONTROL_NAME, sizeof(ctlInfo.ctl_name));
+        fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
+
+        if (fd==-1)
+            return -1;
+
+        if (ioctl(fd, CTLIOCGINFO, &ctlInfo)==-1) {
+            close(fd);
+            continue;
+        }
+
+        sc.sc_id = ctlInfo.ctl_id;
+        sc.sc_len = sizeof(sc);
+        sc.sc_family = AF_SYSTEM;
+        sc.ss_sysaddr = AF_SYS_CONTROL;
+        sc.sc_unit = dev_id+1;
+
+        if (connect(fd, (struct sockaddr *) &sc, sizeof(sc))==-1) {
+            close(fd);
+            continue;
+        }
+
+        printf("tun name: /dev/utun%u\n", dev_id);
+
+        return fd;
+    }
+
+    return -1;
+}
+#else
+int tun_create (_unused_ char *name, _unused_ int mq)
+{
+    for (unsigned dev_id = 0U; dev_id<32U; dev_id++) {
+        char dev_path[11U];
+
+        snprintf(dev_path, sizeof(dev_path), "/dev/tun%u", dev_id);
+
+        int fd = open(dev_path, O_RDWR);
+
+        if (fd!=-1) {
+            printf("tun name: /dev/tun%u\n", dev_id);
+            return fd;
+        }
+    }
+
+    return -1;
+}
+#endif
+
+ssize_t tun_read (int fd, void *data, size_t size)
+{
+    if (!size)
+        return -2;
+
+#ifdef GT_BSD_TUN
+    uint32_t family;
+    struct iovec iov[2] = {
+        { .iov_base = &family, .iov_len = sizeof(family) },
+        { .iov_base = data, .iov_len = size }
+    };
+
+    ssize_t ret = readv(fd, iov, 2);
+#else
+    ssize_t ret = read(fd, data, size);
+#endif
+
+    if (ret==-1) {
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
+
+        if (errno)
+            perror("readv");
+
+        return 0;
+    }
+
+#ifdef GT_BSD_TUN
+    if (ret<(ssize_t) sizeof(family))
+        return 0;
+
+    return ret-sizeof(family);
+#else
+    return ret;
+#endif
+}
+
+ssize_t tun_write (int fd, const void *data, size_t size)
+{
+    if (!size)
+        return -2;
+
+#ifdef GT_BSD_TUN
+    uint32_t family;
+
+    switch (ip_get_version(data, size)) {
+    case 4:
+        family = htonl(AF_INET);
+        break;
+    case 6:
+        family = htonl(AF_INET6);
+        break;
+    default:
+        return -1;
+    }
+
+    struct iovec iov[2] = {
+        { .iov_base = &family, .iov_len = sizeof(family) },
+        { .iov_base = (void *) data, .iov_len = size },
+    };
+
+    ssize_t ret = writev(fd, iov, 2);
+#else
+    ssize_t ret = write(fd, data, size);
+#endif
+
+    if (ret==-1) {
+        if (errno==EAGAIN || errno==EINTR)
+            return -1;
+
+        if (errno)
+            perror("write");
+
+        return 0;
+    }
+
+#ifdef GT_BSD_TUN
+    if (ret<(ssize_t) sizeof(family))
+        return 0;
+
+    return ret-sizeof(family);
+#else
+    return ret;
+#endif
+}