package/network/services/ppp/patches/140-pppd-Fix-compilation-with-older-glibc-or-kernel-head.patch

   1 From 98ec18f098e5ef68e3a8cc6954fcaf5a7fb8b7be Mon Sep 17 00:00:00 2001
   2 From: pali <7141871+pali@users.noreply.github.com>
   3 Date: Mon, 15 Feb 2021 07:54:01 +0100
   4 Subject: [PATCH] pppd: Fix compilation with older glibc or kernel headers
   5  (#248)
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 glibc versions prior to 2.24 do not define SOL_NETLINK and linux kernel
  11 versions prior to 4.3 do not define NETLINK_CAP_ACK. So add fallback
  12 definitions for these macros into pppd/sys-linux.c file.
  13
  14 Also extend description why we call SOL_NETLINK/NETLINK_CAP_ACK option.
  15
  16 Signed-off-by: Pali Rohár <pali@kernel.org>
  17 ---
  18  pppd/sys-linux.c | 18 +++++++++++++++++-
  19  1 file changed, 17 insertions(+), 1 deletion(-)
  20
  21 --- a/pppd/sys-linux.c
  22 +++ b/pppd/sys-linux.c
  23 @@ -125,6 +125,14 @@
  24  #include <linux/netlink.h>
  25  #include <linux/rtnetlink.h>
  26  #include <linux/if_addr.h>
  27 +/* glibc versions prior to 2.24 do not define SOL_NETLINK */
  28 +#ifndef SOL_NETLINK
  29 +#define SOL_NETLINK 270
  30 +#endif
  31 +/* linux kernel versions prior to 4.3 do not define/support NETLINK_CAP_ACK */
  32 +#ifndef NETLINK_CAP_ACK
  33 +#define NETLINK_CAP_ACK 10
  34 +#endif
  35  #endif
  36
  37  #include "pppd.h"
  38 @@ -2843,7 +2851,15 @@ static int append_peer_ipv6_address(unsi
  39      if (fd < 0)
  40          return 0;
  41
  42 -    /* do not ask for error message content */
  43 +    /*
  44 +     * Tell kernel to not send to us payload of acknowledgment error message.
  45 +     * NETLINK_CAP_ACK option is supported since Linux kernel version 4.3 and
  46 +     * older kernel versions always send full payload in acknowledgment netlink
  47 +     * message. We ignore payload of this message as we need only error code,
  48 +     * to check if our set remote peer address request succeeded or failed.
  49 +     * So ignore return value from the following setsockopt() call as setting
  50 +     * option NETLINK_CAP_ACK means for us just a kernel hint / optimization.
  51 +     */
  52      one = 1;
  53      setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, &one, sizeof(one));
  54