[glibc] Add TCP_MD5SIG_FLAG_IFINDEX from Linux 5.6 to netinet/tcp.h.

[glibc] Add TCP_MD5SIG_FLAG_IFINDEX from Linux 5.6 to netinet/tcp.h.

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=06bbe63e367abd5f7b225cbae30d1e487f237c85

commit 06bbe63e367abd5f7b225cbae30d1e487f237c85
Author: Tobias Klauser <tklauser@distanz.ch>
Date:   Tue Nov 28 12:06:43 2023 +0100

    Add TCP_MD5SIG_FLAG_IFINDEX from Linux 5.6 to netinet/tcp.h.
    
    This patch adds the TCP_MD5SIG_FLAG_IFINDEX constant from Linux 5.6 to
    sysdeps/gnu/netinet/tcp.h and updates struct tcp_md5sig accordingly to
    contain the device index.
    
    Reviewed-by: Florian Weimer <fweimer@redhat.com>

Diff:
---
 sysdeps/gnu/netinet/tcp.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sysdeps/gnu/netinet/tcp.h b/sysdeps/gnu/netinet/tcp.h
index 1793724642..b2acbb4350 100644
--- a/sysdeps/gnu/netinet/tcp.h
+++ b/sysdeps/gnu/netinet/tcp.h
@@ -272,6 +272,7 @@ struct tcp_info
 
 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT.  */
 #define TCP_MD5SIG_FLAG_PREFIX	1 /* Address prefix length.  */
+#define TCP_MD5SIG_FLAG_IFINDEX	2 /* Ifindex set.  */
 
 struct tcp_md5sig
 {
@@ -279,7 +280,7 @@ struct tcp_md5sig
   uint8_t	tcpm_flags;			/* Extension flags.  */
   uint8_t	tcpm_prefixlen;			/* Address prefix.  */
   uint16_t	tcpm_keylen;			/* Key length.  */
-  uint32_t	__tcpm_pad;			/* Zero.  */
+  int		tcpm_ifindex;			/* Device index for scope.  */
   uint8_t	tcpm_key[TCP_MD5SIG_MAXKEYLEN];	/* Key (binary).  */
 };