Wg-user: Add wireguard unix socket implementation

Unix socket implementation for wireguard-go.
Use abstract unix sockets on Android

3 files changed, 298 insertions, 1 deletions

diff --git a/sysdep/unix/Makefile b/sysdep/unix/Makefile
index d0d36b5f..ef422342 100644
--- a/sysdep/unix/Makefile
+++ b/sysdep/unix/Makefile
@@ -1,4 +1,4 @@
-src := alloc.c io.c krt.c log.c main.c random.c
+src := alloc.c io.c krt.c log.c main.c random.c wg_user.c
 obj := $(src-o-files)
 $(all-daemon)
 $(cf-local)
diff --git a/sysdep/unix/wg_user.c b/sysdep/unix/wg_user.c
new file mode 100644
index 00000000..9192f952
--- /dev/null
+++ b/sysdep/unix/wg_user.c
@@ -0,0 +1,281 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include "lib/lists.h"
+#include "lib/ip.h"
+#include "lib/socket.h"
+#include "nest/iface.h"
+#include "sysdep/unix/unix.h"
+#include "sysdep/unix/wg_user.h"
+#include "sysdep/linux/wireguard.h"
+
+static
+socklen_t get_socket_path(const char *ifname, char *buf, uint size)
+{
+  int pos = 0;
+
+  if (size < 1)
+    return 0;
+
+#ifdef ANDROID
+  /* Abstract socket */
+  buf[pos++] = 0;
+#endif
+  bsnprintf(buf+pos, size-pos, SOCKET_PATH "%s.sock", ifname);
+  return pos + strlen(buf+pos);
+}
+
+bool wg_has_userspace(const char *ifname)
+{
+  struct stat sb;
+  char tmp[sizeof(struct sockaddr_un)];
+  socklen_t tmplen = get_socket_path(ifname, tmp, sizeof(tmp));
+
+  if (tmplen > 0 && tmp[0] == 0)
+    /* System with abstract socket (Android) always use WireGuard's userspace
+       implementation. */
+    return true;
+  else if (stat(tmp, &sb) == 0)
+    return (sb.st_mode & S_IFMT) == S_IFSOCK;
+  else
+  {
+    DBG(L_TRACE "WG: no socket %s", tmp);
+    return false;
+  }
+}
+
+/* NULL=receiving turned off, returns 1 to clear rx buffer */
+static
+int user_rx_hook(struct birdsock *sk UNUSED, uint size UNUSED)
+{
+  DBG(L_TRACE "WG: RX %p %d", sk, size);
+  rfree(sk);
+  return 1;
+}
+
+static
+void user_tx_hook(struct birdsock *bs)
+{
+  DBG(L_TRACE "WG: TX %p %d", bs, bs->tpos - bs->ttx);
+
+  uint size = (uintptr_t)bs->data;
+
+  if (size > 0)
+  {
+    int res = sk_send(bs, bs->tbsize - size);
+
+    /* Send data, <0=err, >0=ok, 0=sleep */
+    log(L_TRACE "WG: send %d", res);
+
+    if (res != 0)
+    {
+      //rfree(sock);
+      //shutdown(sock->fd, SHUT_WR);
+    }
+
+    bs->data = NULL;
+  }
+}
+
+/* errno or zero if EOF */
+static
+void user_err_hook(struct birdsock *bs, int err)
+{
+  /* if (err == 0) */
+  /*   return; */
+
+  log(L_TRACE "WG: ERR %p %d %s", bs, err, bs->err);
+  rfree(bs);
+}
+
+static void
+wg_puts(const char *str, byte **buf, uint *size)
+{
+  int len = strlen(str);
+  if (0 < len && len < (int)*size)
+  {
+    strcpy(*buf, str);
+    *size -= len;
+    *buf += len;
+  }
+  else
+    *size = 0;
+}
+
+static void
+wg_put_str(const char *key, const char *value, byte **buf, uint *size)
+{
+  char tmp[128];
+
+  int len = snprintf(tmp, sizeof(tmp), "%s=%s\n", key, value);
+  if (0 < len && len < (int)*size)
+  {
+    strcpy(*buf, tmp);
+    *size -= len;
+    *buf += len;
+  }
+  else
+    *size = 0;
+}
+
+static void
+wg_put_u16(const char *key, u16 value, byte **buf, uint *size)
+{
+  char tmp[64];
+
+  int len = snprintf(tmp, sizeof(tmp), "%u", value);
+  if (len > 0)
+    wg_put_str(key, tmp, buf, size);
+  else
+    *size = 0;
+}
+
+static void
+wg_put_bool(const char *key, bool value, byte **buf, uint *size)
+{
+  if (value)
+    wg_put_str(key, "true", buf, size);
+}
+
+static void
+wg_put_key(const char *key, wg_key value, byte **buf, uint *size)
+{
+  char tmp[128];
+
+  for (uint i=0; i < sizeof(wg_key); i++)
+    bsnprintf(tmp+2*i, sizeof(tmp)-2*i, "%02x", value[i]);
+
+  wg_put_str(key, tmp, buf, size);
+}
+
+static void
+wg_put_endpoint(const wg_endpoint *endpoint, byte **buf, uint *size)
+{
+  char tmp[INET6_ADDRSTRLEN + 16];
+  ip_addr ip;
+  struct iface *ifa = NULL;
+  uint port = 0;
+
+  if (sockaddr_read((sockaddr*)&endpoint->addr, endpoint->addr.sa_family,
+		    &ip, &ifa, &port) == 0)
+  {
+    char *pos = NULL;
+
+    if (ipa_is_ip4(ip))
+      pos = ip4_ntop(ipa_to_ip4(ip), tmp);
+    else
+    {
+      tmp[0] = '[';
+      pos = ip6_ntop(ipa_to_ip6(ip), tmp + 1);
+      if (ifa)
+        pos += bsprintf(pos, "%%%u", ifa->index);
+      *pos++ = ']';
+    }
+
+    bsprintf(pos, ":%u", port);
+    wg_put_str("endpoint", tmp, buf, size);
+  }
+}
+
+static void
+wg_put_allowedip(wg_allowedip *allowedip, byte **buf, uint *size)
+{
+  char tmp[INET6_ADDRSTRLEN + 10];
+  ip_addr ip = IP6_NONE;
+
+  switch (allowedip->family)
+  {
+  case AF_INET:
+    ip = ipa_from_in4(allowedip->ip4);
+    break;
+  case AF_INET6:
+    ip = ipa_from_in6(allowedip->ip6);
+    break;
+  default:
+    return;
+  }
+
+  int res = bsnprintf(tmp, sizeof(tmp), "%I/%u", ip, allowedip->cidr);
+
+  if (res < 0)
+  {
+    *size = 0;
+    return;
+  }
+
+  wg_put_str("allowed_ip", tmp, buf, size);
+}
+
+static int
+user_put_device(wg_device *dev, byte **buf, uint *size)
+{
+  wg_put_u16("set", 1, buf, size);
+  wg_put_key("private_key", dev->private_key, buf, size);
+  wg_put_u16("listen_port", dev->listen_port, buf, size);
+  wg_put_bool("replace_peers", dev->flags & WGDEVICE_REPLACE_PEERS, buf, size);
+
+  wg_peer *peer = NULL;
+  wg_for_each_peer(dev, peer)
+  {
+    wg_put_key("public_key", peer->public_key, buf, size);
+    wg_put_endpoint(&peer->endpoint, buf, size);
+    wg_put_bool("replace_allowed_ips", peer->flags & WGPEER_REPLACE_ALLOWEDIPS, buf, size);
+
+    wg_allowedip *allowedip = NULL;
+    wg_for_each_allowedip(peer, allowedip)
+    {
+      wg_put_allowedip(allowedip, buf, size);
+    }
+  }
+  wg_puts("\n", buf, size);
+
+  if (*size > 0)
+    return 0;
+  else
+    return -1;
+}
+
+int
+wg_user_set_device(struct pool *pool,
+		   const char *ifname,
+		   struct wg_device *dev)
+{
+  char path[sizeof(struct sockaddr_un)];
+  socklen_t pathlen = get_socket_path(ifname, path, sizeof(path));
+
+  struct birdsock *sock = sk_new(pool);
+  sock->rx_hook = user_rx_hook;
+  sock->tx_hook = user_tx_hook;
+  sock->err_hook = user_err_hook;
+  sock->fast_rx = 1;
+
+  uint tbsize = 8192;
+  sk_set_tbsize(sock, tbsize);
+  sk_set_rbsize(sock, 16);
+  byte *pos = sock->tbuf;
+  uint size = tbsize;
+  int len = user_put_device(dev, &pos, &size);
+
+  DBG(L_TRACE "WG: put %d %s", size, sock->tbuf);
+
+  if (len < 0)
+  {
+    rfree(sock);
+    return -1;
+  }
+
+  sock->data = (void*)(uintptr_t)size;
+
+  int res = sk_connect_unix(sock, path, pathlen);
+  DBG(L_TRACE "WG: socket %d %d %s", res, sock->fd, path);
+  if (res < 0)
+  {
+    rfree(sock);
+    return -1;
+  }
+
+  /* abort(); */
+  return -1;
+}
diff --git a/sysdep/unix/wg_user.h b/sysdep/unix/wg_user.h
new file mode 100644
index 00000000..5bd9a41a
--- /dev/null
+++ b/sysdep/unix/wg_user.h
@@ -0,0 +1,16 @@
+#ifndef _BIRD_WG_USER_H
+#define _BIRD_WG_USER_H
+
+#include "sysdep/config.h"
+
+#ifndef SOCKET_PATH
+#define SOCKET_PATH PATH_RUNSTATEDIR "/wireguard/"
+#endif /* SOCKET_PATH */
+
+struct pool;
+struct wg_device;
+
+bool wg_has_userspace(const char *ifname);
+int wg_user_set_device(struct pool *pool, const char *ifname, struct wg_device *dev);
+
+#endif  /* _BIRD_WG_USER_H */