[Openvpn-devel,S] Change in openvpn[master]: io_work: pass event_arg object to event handler in case of socket event

Message ID cd9488164f294bf485f57059ac943a8c690ff557-HTML@gerrit.openvpn.net
State Not Applicable
Headers show
Series [Openvpn-devel,S] Change in openvpn[master]: io_work: pass event_arg object to event handler in case of socket event | expand

Commit Message

reynir (Code Review) Nov. 15, 2023, 1:45 p.m. UTC
Attention is currently required from: flichtenheld, plaisthos.

Hello plaisthos, flichtenheld,

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

    http://gerrit.openvpn.net/c/openvpn/+/433?usp=email

to review the following change.


Change subject: io_work: pass event_arg object to event handler in case of socket event
......................................................................

io_work: pass event_arg object to event handler in case of socket event

In order to allow the code to work with multiple listening sockets
it is essential to allow the generic multi_io event handler
to distinguish between the various socket objects.

This can be achieved by passing an event_arg object that contains
a pointer to the link_socket.

This code path is used on clients as well as UDP servers.

Change-Id: I5899081c69bf1aa654d20e607fcdbd589140d474
Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
M src/openvpn/event.h
M src/openvpn/forward.c
M src/openvpn/mtcp.c
3 files changed, 30 insertions(+), 5 deletions(-)



  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/33/433/1

Patch

diff --git a/src/openvpn/event.h b/src/openvpn/event.h
index 0b1f63d..f04318f 100644
--- a/src/openvpn/event.h
+++ b/src/openvpn/event.h
@@ -82,6 +82,12 @@ 
 #define EVENT_METHOD_US_TIMEOUT   (1<<0)
 #define EVENT_METHOD_FAST         (1<<1)
 
+/*
+ * The following constant is used as boundary between integer value
+ * and real addresses when passing arguments to event handlers as (void *)
+ */
+#define MULTI_N           ((void *)16) /* upper bound on MTCP_x */
+
 #ifdef _WIN32
 
 typedef const struct rw_handle *event_t;
diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
index 9cc5c6b..9700c6c 100644
--- a/src/openvpn/forward.c
+++ b/src/openvpn/forward.c
@@ -2164,7 +2164,8 @@ 
     /*
      * Configure event wait based on socket, tuntap flags.
      */
-    socket_set(c->c2.link_socket, c->c2.event_set, socket, (void *)&socket_shift, NULL);
+    socket_set(c->c2.link_socket, c->c2.event_set, socket,
+               &c->c2.link_socket->ev_arg, NULL);
     tun_set(c->c1.tuntap, c->c2.event_set, tuntap, (void *)tun_shift, NULL);
 #if defined(TARGET_LINUX) || defined(TARGET_FREEBSD)
     if (socket & EVENT_READ && c->c2.did_open_tun)
@@ -2227,7 +2228,27 @@ 
                 for (i = 0; i < status; ++i)
                 {
                     const struct event_set_return *e = &esr[i];
-                    c->c2.event_set_status |= ((e->rwflags & 3) << (uintptr_t)e->arg);
+                    uintptr_t shift;
+
+                    if (e->arg >= MULTI_N)
+                    {
+                        struct event_arg *ev_arg = (struct event_arg *)e->arg;
+                        if (ev_arg->type != EVENT_ARG_LINK_SOCKET)
+                        {
+                            c->c2.event_set_status = ES_ERROR;
+                            msg(D_LINK_ERRORS,
+                                "io_work: non socket event delivered");
+                            return;
+                        }
+
+                        shift = socket_shift;
+                    }
+                    else
+                    {
+                        shift = (uintptr_t)e->arg;
+                    }
+
+                    c->c2.event_set_status |= ((e->rwflags & 3) << shift);
                 }
             }
             else if (status == 0)
diff --git a/src/openvpn/mtcp.c b/src/openvpn/mtcp.c
index de1d24f..3772acf 100644
--- a/src/openvpn/mtcp.c
+++ b/src/openvpn/mtcp.c
@@ -61,8 +61,6 @@ 
 #define MTCP_FILE_CLOSE_WRITE ((void *)5)
 #define MTCP_DCO        ((void *)6)
 
-#define MTCP_N           ((void *)16) /* upper bound on MTCP_x */
-
 struct ta_iow_flags
 {
     unsigned int flags;
@@ -696,7 +694,7 @@ 
         struct event_arg *ev_arg = (struct event_arg *)e->arg;
 
         /* incoming data for instance or listening socket? */
-        if (e->arg >= MTCP_N)
+        if (e->arg >= MULTI_N)
         {
             switch (ev_arg->type)
             {