[Openvpn-devel,v4,1/8] Replace TUN_MTU_SIZE with frame->tun_mtu

Message ID 20220210162632.3309974-1-arne@rfc2549.org
State Accepted
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Series
  • [Openvpn-devel,v4,1/8] Replace TUN_MTU_SIZE with frame->tun_mtu
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Commit Message

Arne Schwabe Feb. 10, 2022, 4:26 p.m.
This always uses the configured MTU size instead relying on the calculated
MTU size.

Patch v4: Fix a few overlooked TUN_MTU_SIZE.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
---
 src/openvpn/forward.c |  2 +-
 src/openvpn/init.c    | 20 ++++++++++----------
 src/openvpn/mtu.c     |  4 ++--
 src/openvpn/mtu.h     |  5 -----
 4 files changed, 13 insertions(+), 18 deletions(-)

Comments

Gert Doering Feb. 11, 2022, 8:58 a.m. | #1
Acked-by: Gert Doering <gert@greenie.muc.de>

Code change looks very straight forward :-)

Passes all my torture tests on client and server (except frame max 
setting on P2P TAP, but that's known and will be fixed at the end 
of the series).

For reference, this was 19/21 in v1 and 12/14 in v3 of the series,
which could not go in because it broke compilation.  The difference
v3 -> v4 is "more TUN_MTU_SIZE() calls get converted" - all of
these in code parts that got removed in other parts of the v3 patch
series, but breaking compilation nonetheless.

Doing this as 01/08 now will also magically fix the "ifconfig has
the wrong mtu value" problem that made me stall 09/14 v3.

Your patch has been applied to the master branch.

commit 364b7b4f04985600e0a0a46e79555379b5df9977
Author: Arne Schwabe
Date:   Thu Feb 10 17:26:25 2022 +0100

     Replace TUN_MTU_SIZE with frame->tun_mtu

     Signed-off-by: Arne Schwabe <arne@rfc2549.org>
     Acked-by: Gert Doering <gert@greenie.muc.de>
     Message-Id: <20220210162632.3309974-1-arne@rfc2549.org>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23752.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering

Patch

diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
index af041179..dcc430d4 100644
--- a/src/openvpn/forward.c
+++ b/src/openvpn/forward.c
@@ -1381,7 +1381,7 @@  ipv6_send_icmp_unreachable(struct context *c, struct buffer *buf, bool client)
      * packet
      */
     int max_payload_size = min_int(MAX_ICMPV6LEN,
-                                   TUN_MTU_SIZE(&c->c2.frame) - icmpheader_len);
+                                   c->c2.frame.tun_mtu - icmpheader_len);
     int payload_len = min_int(max_payload_size, BLEN(&inputipbuf));
 
     pip6out.payload_len = htons(sizeof(struct openvpn_icmp6hdr) + payload_len);
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 8e1e43cb..4c799f19 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -1735,7 +1735,7 @@  do_open_tun(struct context *c)
                                              c->options.dev_type,
                                              c->options.dev_node,
                                              &gc);
-        do_ifconfig(c->c1.tuntap, guess, TUN_MTU_SIZE(&c->c2.frame), c->c2.es,
+        do_ifconfig(c->c1.tuntap, guess, c->c2.frame.tun_mtu, c->c2.es,
                     &c->net_ctx);
     }
 
@@ -1766,7 +1766,7 @@  do_open_tun(struct context *c)
         && ifconfig_order() == IFCONFIG_AFTER_TUN_OPEN)
     {
         do_ifconfig(c->c1.tuntap, c->c1.tuntap->actual_name,
-                    TUN_MTU_SIZE(&c->c2.frame), c->c2.es, &c->net_ctx);
+                    c->c2.frame.tun_mtu, c->c2.es, &c->net_ctx);
     }
 
     /* run the up script */
@@ -1778,7 +1778,7 @@  do_open_tun(struct context *c)
                 c->c1.tuntap->adapter_index,
 #endif
                 dev_type_string(c->options.dev, c->options.dev_type),
-                TUN_MTU_SIZE(&c->c2.frame),
+                c->c2.frame.tun_mtu,
                 print_in_addr_t(c->c1.tuntap->local, IA_EMPTY_IF_UNDEF, &gc),
                 print_in_addr_t(c->c1.tuntap->remote_netmask, IA_EMPTY_IF_UNDEF, &gc),
                 "init",
@@ -1827,7 +1827,7 @@  else
                     c->c1.tuntap->adapter_index,
 #endif
                     dev_type_string(c->options.dev, c->options.dev_type),
-                    TUN_MTU_SIZE(&c->c2.frame),
+                    c->c2.frame.tun_mtu,
                     print_in_addr_t(c->c1.tuntap->local, IA_EMPTY_IF_UNDEF, &gc),
                     print_in_addr_t(c->c1.tuntap->remote_netmask, IA_EMPTY_IF_UNDEF, &gc),
                     "restart",
@@ -1906,7 +1906,7 @@  do_close_tun(struct context *c, bool force)
                             adapter_index,
 #endif
                             NULL,
-                            TUN_MTU_SIZE(&c->c2.frame),
+                            c->c2.frame.tun_mtu,
                             print_in_addr_t(local, IA_EMPTY_IF_UNDEF, &gc),
                             print_in_addr_t(remote_netmask, IA_EMPTY_IF_UNDEF, &gc),
                             "init",
@@ -1936,7 +1936,7 @@  do_close_tun(struct context *c, bool force)
                         adapter_index,
 #endif
                         NULL,
-                        TUN_MTU_SIZE(&c->c2.frame),
+                        c->c2.frame.tun_mtu,
                         print_in_addr_t(local, IA_EMPTY_IF_UNDEF, &gc),
                         print_in_addr_t(remote_netmask, IA_EMPTY_IF_UNDEF, &gc),
                         "init",
@@ -1974,7 +1974,7 @@  do_close_tun(struct context *c, bool force)
                             adapter_index,
 #endif
                             NULL,
-                            TUN_MTU_SIZE(&c->c2.frame),
+                            c->c2.frame.tun_mtu,
                             print_in_addr_t(local, IA_EMPTY_IF_UNDEF, &gc),
                             print_in_addr_t(remote_netmask, IA_EMPTY_IF_UNDEF, &gc),
                             "restart",
@@ -2154,7 +2154,7 @@  void adjust_mtu_peerid(struct context *c)
     {
         msg(M_WARN, "OPTIONS IMPORT: WARNING: peer-id set, but link-mtu"
                     " fixed by config - reducing tun-mtu to %d, expect"
-                    " MTU problems", TUN_MTU_SIZE(&c->c2.frame));
+                    " MTU problems", c->c2.frame.tun_mtu);
     }
 }
 
@@ -3185,11 +3185,11 @@  do_init_frame(struct context *c)
 
 #ifdef ENABLE_FRAGMENT
     if ((c->options.ce.mssfix || c->options.ce.fragment)
-        && TUN_MTU_SIZE(&c->c2.frame_fragment) != ETHERNET_MTU)
+        && c->c2.frame.tun_mtu != ETHERNET_MTU)
     {
         msg(M_WARN,
             "WARNING: normally if you use --mssfix and/or --fragment, you should also set --tun-mtu %d (currently it is %d)",
-            ETHERNET_MTU, TUN_MTU_SIZE(&c->c2.frame_fragment));
+            ETHERNET_MTU, c->c2.frame.tun_mtu);
     }
 #endif
 }
diff --git a/src/openvpn/mtu.c b/src/openvpn/mtu.c
index d014d2b8..783fcc5f 100644
--- a/src/openvpn/mtu.c
+++ b/src/openvpn/mtu.c
@@ -229,9 +229,9 @@  frame_finalize(struct frame *frame,
         frame->link_mtu = link_mtu;
     }
 
-    if (TUN_MTU_SIZE(frame) < TUN_MTU_MIN)
+    if (frame->tun_mtu < TUN_MTU_MIN)
     {
-        msg(M_WARN, "TUN MTU value (%d) must be at least %d", TUN_MTU_SIZE(frame), TUN_MTU_MIN);
+        msg(M_WARN, "TUN MTU value (%d) must be at least %d", frame->tun_mtu, TUN_MTU_MIN);
         frame_print(frame, M_FATAL, "MTU is too small");
     }
 
diff --git a/src/openvpn/mtu.h b/src/openvpn/mtu.h
index ef8ac4ab..7a6cdcb4 100644
--- a/src/openvpn/mtu.h
+++ b/src/openvpn/mtu.h
@@ -184,11 +184,6 @@  struct options;
  */
 #define TUN_LINK_DELTA(f)        ((f)->extra_frame + (f)->extra_tun)
 
-/*
- * This is the size to "ifconfig" the tun or tap device.
- */
-#define TUN_MTU_SIZE(f)          ((f)->link_mtu - TUN_LINK_DELTA(f))
-
 /*
  * This is the maximum packet size that we need to be able to
  * read from or write to a tun or tap device.  For example,