Wireguard: Refactor unix socket implementation

Move unix socket implementation for wireguard-go to sysdep/unix/.

3 files changed, 262 insertions, 1 deletions

diff --git a/sysdep/unix/Makefile b/sysdep/unix/Makefile
index f592399c..5272408b 100644
--- a/sysdep/unix/Makefile
+++ b/sysdep/unix/Makefile
@@ -1,4 +1,4 @@
-src := io.c krt.c log.c main.c random.c
+src := 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..a387e971
--- /dev/null
+++ b/sysdep/unix/wg_user.c
@@ -0,0 +1,247 @@
+#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
+char *get_socket_path(const char *ifname, char *buf, uint size)
+{
+  bsnprintf(buf, size, SOCKET_PATH "%s.sock", ifname);
+  return buf;
+}
+
+bool wg_has_userspace(const char *ifname)
+{
+  struct stat sb;
+  char tmp[sizeof(struct sockaddr_un)];
+
+  if (stat(get_socket_path(ifname, tmp, sizeof(tmp)), &sb) == 0)
+    return (sb.st_mode & S_IFMT) == S_IFSOCK;
+  else
+    {
+      log(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)
+{
+  log(L_TRACE "WG: RX %d", size);
+  return 1;
+}
+
+static
+void user_tx_hook(struct birdsock *bs UNUSED)
+{
+  log(L_TRACE "WG: TX");
+}
+
+/* errno or zero if EOF */
+static
+void user_err_hook(struct birdsock *bs, int err)
+{
+  /* if (err == 0) */
+  /*   return; */
+
+  log(L_TRACE "WG: ERR %d %s", err, bs->err);
+  if (bs->fd >= 0)
+    close(bs->fd);
+  bs->fd = -1;
+}
+
+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)];
+
+  bsnprintf(path, sizeof(path), SOCKET_PATH "%s.sock", ifname);
+
+  struct birdsock *sock = sk_new(pool);
+  sock->rx_hook = user_rx_hook;
+  sock->tx_hook = user_tx_hook;
+  sock->err_hook = user_err_hook;
+  int res = sk_connect_unix(sock, path);
+  log(L_TRACE "WG: socket %d %d %s", res, sock->fd, path);
+  if (res < 0)
+    return -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);
+
+  log(L_TRACE "WG: put %d %s", size, sock->tbuf);
+
+  if (len < 0)
+    {
+      /* FIXME close */
+      return -1;
+    }
+  res = sk_send(sock, tbsize - size);
+  /* Send data, <0=err, >0=ok, 0=sleep */
+  log(L_TRACE "WG: send %d", res);
+
+  /* abort(); */
+  return -1;
+}
diff --git a/sysdep/unix/wg_user.h b/sysdep/unix/wg_user.h
new file mode 100644
index 00000000..a5e4251a
--- /dev/null
+++ b/sysdep/unix/wg_user.h
@@ -0,0 +1,14 @@
+#ifndef _BIRD_WG_USER_H
+#define _BIRD_WG_USER_H
+
+#include "sysdep/config.h"
+
+#define SOCKET_PATH PATH_RUNSTATEDIR "/wireguard/"
+
+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 */