PaulHowarth/Blog/2010-07-23

Friday 23rd July 2010

Fedora Project

Raised Bug #617625 on ppp in Rawhide, which currently fails to build from source with this error:

In file included from plugin.c:53:0:
/usr/include/linux/if_pppox.h:75:25: error: field 'pppol2tp' has incomplete type

The problem is that ppp bundles a copy of the linux/if_pppol2tp.h kernel header, which has been modified in recent kernels to add support for L2TPv3, specifically by adding a definition for struct pppol2tpv3_addr, which is needed by linux/if_pppox.h, which has similarly been updated for L2TPv3. The build fails because the preprocessor uses the bundled copy of linux/if_pppol2tp.h rather than the system one and hence can't find the definition of struct pppol2tpv3_addr, resulting in the error. The simplest fix is just to patch the bundled copy of linux/if_pppol2tp.h to include the struct pppol2tpv3_addr definition, as with this patch:

--- ppp-2.4.5/include/linux/if_pppol2tp.h       2009-11-16 22:26:07.000000000 +0000
+++ ppp-2.4.5/include/linux/if_pppol2tp.h       2010-07-16 22:35:22.000000000 +0100
@@ -32,6 +32,20 @@
        __u16 d_tunnel, d_session;      /* For sending outgoing packets */
 };
 
+/* The L2TPv3 protocol changes tunnel and session ids from 16 to 32
+ * bits. So we need a different sockaddr structure.
+ */
+struct pppol2tpv3_addr {
+       pid_t   pid;                    /* pid that owns the fd.
+                                        * 0 => current */
+       int     fd;                     /* FD of UDP or IP socket to use */
+
+       struct sockaddr_in addr;        /* IP address and port to send to */
+
+       __u32 s_tunnel, s_session;      /* For matching incoming packets */
+       __u32 d_tunnel, d_session;      /* For sending outgoing packets */
+};
+
 /* Socket options:
  * DEBUG       - bitmask of debug message categories
  * SENDSEQ     - 0 => don't send packets with sequence numbers

Update: Further patching is needed for current kernels - see entry for 29th May 2012
Submitted a tidyp package for review

Local Packages

Updated perl-Module-Build to include inc::latest in the Rawhide build again, now that Bug #607505 is resolved
Updated ppp to fix the Rawhide build as per the Fedora version, and to include updated patches from Fedora, namely to fix a missing line in the example script ip-up.local.add (#613717) and to include the pppol2tp plug-ins (#572174); curiously, the latter bug is only currently fixed in Fedora 12