diff options
| author |   mcbride <mcbride@openbsd.org> | 2004-10-28 19:22:52 +0000 |
|---|---|---|
| committer | mcbride <mcbride@openbsd.org> | 2004-10-28 19:22:52 +0000 |
| commit | 64c77b9332c5892d33899e1580df890d2afb4ad0 (patch) | |
| tree | 5f7d36834172b8224379283800f9e6cf86efbd41 /sys/netinet/tcp_input.c | |
| parent | need to map the regs though lasi used to save us before (diff) | |
| download | wireguard-openbsd-64c77b9332c5892d33899e1580df890d2afb4ad0.tar.xz wireguard-openbsd-64c77b9332c5892d33899e1580df890d2afb4ad0.zip | |
Modulate tcp_now by a random amount on a per-connection basis.
ok markus@ frantzen@
Diffstat (limited to 'sys/netinet/tcp_input.c')
| -rw-r--r-- | sys/netinet/tcp_input.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 68b04e37a04..57fc27065f6 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -1,4 +1,4 @@ -/* $OpenBSD: tcp_input.c,v 1.176 2004/09/22 21:33:53 deraadt Exp $ */ +/* $OpenBSD: tcp_input.c,v 1.177 2004/10/28 19:22:52 mcbride Exp $ */ /* $NetBSD: tcp_input.c,v 1.23 1996/02/13 23:43:44 christos Exp $ */ /* @@ -932,6 +932,10 @@ after_listen: if (tcp_dooptions(tp, optp, optlen, th, m, iphlen, &opti)) goto drop; + /* subtract out the tcp timestamp modulator */ + if (opti.ts_present) + opti.ts_ecr -= tp->ts_modulate; + #ifdef TCP_SACK if (tp->sack_enable) { tp->rcv_laststart = th->th_seq; /* last rec'vd segment*/ @@ -3235,7 +3239,7 @@ do { \ timeout_add(&(sc)->sc_timer, (sc)->sc_rxtcur * (hz / PR_SLOWHZ)); \ } while (/*CONSTCOND*/0) -#define SYN_CACHE_TIMESTAMP(sc) tcp_now +#define SYN_CACHE_TIMESTAMP(sc) tcp_now + (sc)->sc_modulate void syn_cache_init() @@ -3659,6 +3663,7 @@ syn_cache_get(src, dst, th, hlen, tlen, so, m) tp->sack_enable = sc->sc_flags & SCF_SACK_PERMIT; #endif + tp->ts_modulate = sc->sc_modulate; tp->iss = sc->sc_iss; tp->irs = sc->sc_irs; tcp_sendseqinit(tp); @@ -4114,6 +4119,7 @@ syn_cache_respond(sc, m) u_int32_t *lp = (u_int32_t *)(optp); /* Form timestamp option as shown in appendix A of RFC 1323. */ *lp++ = htonl(TCPOPT_TSTAMP_HDR); + sc->sc_modulate = arc4random(); *lp++ = htonl(SYN_CACHE_TIMESTAMP(sc)); *lp = htonl(sc->sc_timestamp); optp += TCPOLEN_TSTAMP_APPA; |