From 5260d10c985fd87e1d1aaed3c437cf272af024e0 Mon Sep 17 00:00:00 2001 From: Kristof Provost Date: Thu, 20 May 2021 11:54:41 +0200 Subject: [PATCH] pf: syncookie support Import OpenBSD's syncookie support for pf. This feature help pf resist TCP SYN floods by only creating states once the remote host completes the TCP handshake rather than when the initial SYN packet is received. This is accomplished by using the initial sequence numbers to encode a cookie (hence the name) in the SYN+ACK response and verifying this on receipt of the client ACK. Reviewed by: kbowling Obtained from: OpenBSD MFC after: 1 week Sponsored by: Modirum MDPay Differential Revision: https://reviews.freebsd.org/D31138 --- newlib/libc/sys/rtems/include/netinet/tcp.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/newlib/libc/sys/rtems/include/netinet/tcp.h b/newlib/libc/sys/rtems/include/netinet/tcp.h index 45bece9fa..a79dbeaad 100644 --- a/newlib/libc/sys/rtems/include/netinet/tcp.h +++ b/newlib/libc/sys/rtems/include/netinet/tcp.h @@ -105,6 +105,8 @@ struct tcphdr { #define TCPOPT_FAST_OPEN 34 #define TCPOLEN_FAST_OPEN_EMPTY 2 +#define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */ + /* Miscellaneous constants */ #define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at receiver side */ #define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */