implement a sloppy tcpstate tracker which does not look at sequence

numbers at all. scary consequences; only tobe used in very specific
situations where you don't see all packets of a connection, e. g.
asymmetric routing. ok ryan reyk theo

1 files changed, 63 insertions, 6 deletions

diff --git a/sys/net/pf.c b/sys/net/pf.c
index ad18ee0e632..daebc33c46d 100644
--- a/sys/net/pf.c
+++ b/sys/net/pf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf.c,v 1.582 2008/06/09 07:07:16 djm Exp $ */
+/*	$OpenBSD: pf.c,v 1.583 2008/06/10 04:24:17 henning Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -183,10 +183,13 @@ int			 pf_test_fragment(struct pf_rule **, int,
 			    struct pfi_kif *, struct mbuf *, void *,
 			    struct pf_pdesc *, struct pf_rule **,
 			    struct pf_ruleset **);
-int			 pf_tcp_seqtrack_full(struct pf_state_peer *,
+int			 pf_tcp_track_full(struct pf_state_peer *,
 			    struct pf_state_peer *, struct pf_state **,
 			    struct pfi_kif *, struct mbuf *, int,
 			    struct pf_pdesc *, u_short *, int *);
+int			pf_tcp_track_sloppy(struct pf_state_peer *,
+			    struct pf_state_peer *, struct pf_state **,
+			    struct pf_pdesc *, u_short *);
 int			 pf_test_state_tcp(struct pf_state **, int,
 			    struct pfi_kif *, struct mbuf *, int,
 			    void *, struct pf_pdesc *, u_short *);
@@ -3403,6 +3406,8 @@ cleanup:
 		s->anchor.ptr = a;
 		STATE_INC_COUNTERS(s);
 		s->allow_opts = r->allow_opts;
+		if (r->rule_flag & PFRULE_STATESLOPPY)
+			s->sloppy = 1;
 		s->log = r->log & PF_LOG_ALL;
 		if (nr != NULL)
 			s->log |= nr->log & PF_LOG_ALL;
@@ -3648,7 +3653,7 @@ pf_test_fragment(struct pf_rule **rm, int direction, struct pfi_kif *kif,
 }
 
 int
-pf_tcp_seqtrack_full(struct pf_state_peer *src, struct pf_state_peer *dst,
+pf_tcp_track_full(struct pf_state_peer *src, struct pf_state_peer *dst,
 	struct pf_state **state, struct pfi_kif *kif, struct mbuf *m, int off,
 	struct pf_pdesc *pd, u_short *reason, int *copyback)
 {
@@ -3976,6 +3981,53 @@ pf_tcp_seqtrack_full(struct pf_state_peer *src, struct pf_state_peer *dst,
 }
 
 int
+pf_tcp_track_sloppy(struct pf_state_peer *src, struct pf_state_peer *dst,
+	struct pf_state **state, struct pf_pdesc *pd, u_short *reason)
+{
+	struct tcphdr		*th = pd->hdr.tcp;
+
+	if (th->th_flags & TH_SYN)
+		if (src->state < TCPS_SYN_SENT)
+			src->state = TCPS_SYN_SENT;
+	if (th->th_flags & TH_FIN)
+		if (src->state < TCPS_CLOSING)
+			src->state = TCPS_CLOSING;
+	if (th->th_flags & TH_ACK) {
+		if (dst->state == TCPS_SYN_SENT) {
+			dst->state = TCPS_ESTABLISHED;
+			if (src->state == TCPS_ESTABLISHED &&
+			    (*state)->src_node != NULL &&
+			    pf_src_connlimit(state)) {
+				REASON_SET(reason, PFRES_SRCLIMIT);
+				return (PF_DROP);
+			}
+		} else if (dst->state == TCPS_CLOSING)
+			dst->state = TCPS_FIN_WAIT_2;
+	}
+	if (th->th_flags & TH_RST)
+		src->state = dst->state = TCPS_TIME_WAIT;
+
+	/* update expire time */
+	(*state)->expire = time_second;
+	if (src->state >= TCPS_FIN_WAIT_2 &&
+	    dst->state >= TCPS_FIN_WAIT_2)
+		(*state)->timeout = PFTM_TCP_CLOSED;
+	else if (src->state >= TCPS_CLOSING &&
+	    dst->state >= TCPS_CLOSING)
+		(*state)->timeout = PFTM_TCP_FIN_WAIT;
+	else if (src->state < TCPS_ESTABLISHED ||
+	    dst->state < TCPS_ESTABLISHED)
+		(*state)->timeout = PFTM_TCP_OPENING;
+	else if (src->state >= TCPS_CLOSING ||
+	    dst->state >= TCPS_CLOSING)
+		(*state)->timeout = PFTM_TCP_CLOSING;
+	else
+		(*state)->timeout = PFTM_TCP_ESTABLISHED;
+
+	return (PF_PASS);
+}
+
+int
 pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
     struct mbuf *m, int off, void *h, struct pf_pdesc *pd,
     u_short *reason)
@@ -4110,9 +4162,14 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 		return (PF_DROP);
 	}
 
-	if (pf_tcp_seqtrack_full(src, dst, state, kif, m, off, pd, reason,
-	    &copyback) == PF_DROP)
-		return (PF_DROP);
+	if ((*state)->sloppy) {
+		if (pf_tcp_track_sloppy(src, dst, state, pd, reason) == PF_DROP)
+			return (PF_DROP);
+	} else {
+		if (pf_tcp_track_full(src, dst, state, kif, m, off, pd, reason,
+		    &copyback) == PF_DROP)
+			return (PF_DROP);
+	}
 
 	/* translate source/destination address, if necessary */
 	if ((*state)->key[PF_SK_WIRE] != (*state)->key[PF_SK_STACK]) {