diff mbox series

[Openvpn-devel,S] Change in openvpn[master]: Ensure that the AF_UNIX socket pair has at least 65k of buffer space

Message ID e1b646cae1aace36365e2c63040d8af1f305599d-HTML@gerrit.openvpn.net
State Superseded
Headers show
Series [Openvpn-devel,S] Change in openvpn[master]: Ensure that the AF_UNIX socket pair has at least 65k of buffer space | expand

Commit Message

plaisthos (Code Review) Sept. 19, 2024, 2:06 p.m. UTC 
Attention is currently required from: flichtenheld.

Hello flichtenheld,

I'd like you to do a code review.
Please visit

    http://gerrit.openvpn.net/c/openvpn/+/754?usp=email

to review the following change.


Change subject: Ensure that the AF_UNIX socket pair has at least 65k of buffer space
......................................................................

Ensure that the AF_UNIX socket pair has at least 65k of buffer space

Without this change, pinging a lwipovpn client with something like a
3000 byte payload on macOS often fails as the default buffer sizes on
macOS are 2048 for send and 4096 for receive.

Change-Id: Ice015df81543c01094479929f0cb3075ca4f3813
Signed-off-by: Arne Schwabe <arne@rfc2549.org>
---
M src/openvpn/socket.c
M src/openvpn/socket.h
M src/openvpn/tun_afunix.c
3 files changed, 29 insertions(+), 6 deletions(-)



  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/54/754/1
diff mbox series

Patch

diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index 6c790a0..7b1e603 100644
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -890,20 +890,23 @@ 
 #endif
 }
 
-static void
-socket_set_buffers(socket_descriptor_t fd, const struct socket_buffer_size *sbs)
+void
+socket_set_buffers(socket_descriptor_t fd, const struct socket_buffer_size *sbs,
+                   bool reduce_size)
 {
     if (sbs)
     {
         const int sndbuf_old = socket_get_sndbuf(fd);
         const int rcvbuf_old = socket_get_rcvbuf(fd);
 
-        if (sbs->sndbuf)
+        if (sbs->sndbuf
+            && (reduce_size || sndbuf_old < sbs->sndbuf))
         {
             socket_set_sndbuf(fd, sbs->sndbuf);
         }
 
-        if (sbs->rcvbuf)
+        if (sbs->rcvbuf
+            && (reduce_size || rcvbuf_old < sbs->rcvbuf))
         {
             socket_set_rcvbuf(fd, sbs->rcvbuf);
         }
@@ -986,7 +989,7 @@ 
     {
         ls->socket_buffer_sizes.sndbuf = sndbuf;
         ls->socket_buffer_sizes.rcvbuf = rcvbuf;
-        socket_set_buffers(ls->sd, &ls->socket_buffer_sizes);
+        socket_set_buffers(ls->sd, &ls->socket_buffer_sizes, true);
     }
 }
 
@@ -1136,7 +1139,7 @@ 
     sock->info.af = addr->ai_family;
 
     /* set socket buffers based on --sndbuf and --rcvbuf options */
-    socket_set_buffers(sock->sd, &sock->socket_buffer_sizes);
+    socket_set_buffers(sock->sd, &sock->socket_buffer_sizes, true);
 
     /* set socket to --mark packets with given value */
     socket_set_mark(sock->sd, sock->mark);
diff --git a/src/openvpn/socket.h b/src/openvpn/socket.h
index bbdabfb..2e583af 100644
--- a/src/openvpn/socket.h
+++ b/src/openvpn/socket.h
@@ -157,6 +157,18 @@ 
     int sndbuf;
 };
 
+/**
+ * Sets the receive and send buffer sizes of a socket descriptor.
+ *
+ * @param fd            The socket to modify
+ * @param sbs           new sizes.
+ * @param reduce_size   apply the new size even if smaller than current one
+ */
+void
+socket_set_buffers(socket_descriptor_t fd,
+                   const struct socket_buffer_size *sbs,
+                   bool reduce_size);
+
 /*
  * This is the main socket structure used by OpenVPN.  The SOCKET_
  * defines try to abstract away our implementation differences between
diff --git a/src/openvpn/tun_afunix.c b/src/openvpn/tun_afunix.c
index 27cdb01..d41c05a 100644
--- a/src/openvpn/tun_afunix.c
+++ b/src/openvpn/tun_afunix.c
@@ -35,6 +35,7 @@ 
 #include "wfp_block.h"
 #include "argv.h"
 #include "options.h"
+#include "socket.h"
 
 #if defined(AF_UNIX) && !defined(WIN32)
 /* Windows does implement some AF_UNIX functionality but key features
@@ -80,6 +81,13 @@ 
         return;
     }
 
+
+    /* Ensure that the buffer sizes are decently sized. Otherwise macOS will
+     * just have 2048 */
+    struct socket_buffer_size newsizes = {65536, 65536 };
+    socket_set_buffers(fds[0], &newsizes, false);
+    socket_set_buffers(fds[1], &newsizes, false);
+
     /* Use the first file descriptor for our side and avoid passing it
      * to the child */
     tt->fd = fds[1];