factor out the tcp sequence number tracking from pf_test_state_tcp

ok mcbride

1 files changed, 157 insertions, 144 deletions

diff --git a/sys/net/pf.c b/sys/net/pf.c
index b221da330e1..4ee915b2e83 100644
--- a/sys/net/pf.c
+++ b/sys/net/pf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf.c,v 1.580 2008/06/08 17:23:19 henning Exp $ */
+/*	$OpenBSD: pf.c,v 1.581 2008/06/08 21:30:44 henning Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -183,6 +183,10 @@ 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 *,
+			    struct pf_state_peer *, struct pf_state **,
+			    struct pfi_kif *, struct mbuf *, int,
+			    struct pf_pdesc *, u_short *, int *);
 int			 pf_test_state_tcp(struct pf_state **, int,
 			    struct pfi_kif *, struct mbuf *, int,
 			    void *, struct pf_pdesc *, u_short *);
@@ -3644,143 +3648,15 @@ pf_test_fragment(struct pf_rule **rm, int direction, struct pfi_kif *kif,
 }
 
 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)
+pf_tcp_seqtrack_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)
 {
-	struct pf_state_key_cmp	 key;
 	struct tcphdr		*th = pd->hdr.tcp;
 	u_int16_t		 win = ntohs(th->th_win);
 	u_int32_t		 ack, end, seq, orig_seq;
 	u_int8_t		 sws, dws;
 	int			 ackskew;
-	int			 copyback = 0;
-	struct pf_state_peer	*src, *dst;
-	struct pf_state_key	*sk;
-
-	key.af = pd->af;
-	key.proto = IPPROTO_TCP;
-	if (direction == PF_IN)	{	/* wire side, straight */
-		PF_ACPY(&key.addr[0], pd->src, key.af);
-		PF_ACPY(&key.addr[1], pd->dst, key.af);
-		key.port[0] = th->th_sport;
-		key.port[1] = th->th_dport;
-	} else {			/* stack side, reverse */
-		PF_ACPY(&key.addr[1], pd->src, key.af);
-		PF_ACPY(&key.addr[0], pd->dst, key.af);
-		key.port[1] = th->th_sport;
-		key.port[0] = th->th_dport;
-	}
-
-	STATE_LOOKUP(kif, &key, direction, *state);
-
-	if (direction == (*state)->direction) {
-		src = &(*state)->src;
-		dst = &(*state)->dst;
-	} else {
-		src = &(*state)->dst;
-		dst = &(*state)->src;
-	}
-
-	sk = (*state)->key[pd->didx];
-
-	if ((*state)->src.state == PF_TCPS_PROXY_SRC) {
-		if (direction != (*state)->direction) {
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_SYNPROXY_DROP);
-		}
-		if (th->th_flags & TH_SYN) {
-			if (ntohl(th->th_seq) != (*state)->src.seqlo) {
-				REASON_SET(reason, PFRES_SYNPROXY);
-				return (PF_DROP);
-			}
-			pf_send_tcp((*state)->rule.ptr, pd->af, pd->dst,
-			    pd->src, th->th_dport, th->th_sport,
-			    (*state)->src.seqhi, ntohl(th->th_seq) + 1,
-			    TH_SYN|TH_ACK, 0, (*state)->src.mss, 0, 1,
-			    0, NULL, NULL);
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_SYNPROXY_DROP);
-		} else if (!(th->th_flags & TH_ACK) ||
-		    (ntohl(th->th_ack) != (*state)->src.seqhi + 1) ||
-		    (ntohl(th->th_seq) != (*state)->src.seqlo + 1)) {
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_DROP);
-		} else if ((*state)->src_node != NULL &&
-		    pf_src_connlimit(state)) {
-			REASON_SET(reason, PFRES_SRCLIMIT);
-			return (PF_DROP);
-		} else
-			(*state)->src.state = PF_TCPS_PROXY_DST;
-	}
-	if ((*state)->src.state == PF_TCPS_PROXY_DST) {
-		if (direction == (*state)->direction) {
-			if (((th->th_flags & (TH_SYN|TH_ACK)) != TH_ACK) ||
-			    (ntohl(th->th_ack) != (*state)->src.seqhi + 1) ||
-			    (ntohl(th->th_seq) != (*state)->src.seqlo + 1)) {
-				REASON_SET(reason, PFRES_SYNPROXY);
-				return (PF_DROP);
-			}
-			(*state)->src.max_win = MAX(ntohs(th->th_win), 1);
-			if ((*state)->dst.seqhi == 1)
-				(*state)->dst.seqhi = htonl(arc4random());
-			pf_send_tcp((*state)->rule.ptr, pd->af,
-			    &sk->addr[pd->sidx], &sk->addr[pd->didx],
-			    sk->port[pd->sidx], sk->port[pd->didx],
-			    (*state)->dst.seqhi, 0, TH_SYN, 0,
-			    (*state)->src.mss, 0, 0, (*state)->tag, NULL, NULL);
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_SYNPROXY_DROP);
-		} else if (((th->th_flags & (TH_SYN|TH_ACK)) !=
-		    (TH_SYN|TH_ACK)) ||
-		    (ntohl(th->th_ack) != (*state)->dst.seqhi + 1)) {
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_DROP);
-		} else {
-			(*state)->dst.max_win = MAX(ntohs(th->th_win), 1);
-			(*state)->dst.seqlo = ntohl(th->th_seq);
-			pf_send_tcp((*state)->rule.ptr, pd->af, pd->dst,
-			    pd->src, th->th_dport, th->th_sport,
-			    ntohl(th->th_ack), ntohl(th->th_seq) + 1,
-			    TH_ACK, (*state)->src.max_win, 0, 0, 0,
-			    (*state)->tag, NULL, NULL);
-			pf_send_tcp((*state)->rule.ptr, pd->af,
-			    &sk->addr[pd->sidx], &sk->addr[pd->didx],
-			    sk->port[pd->sidx], sk->port[pd->didx],
-			    (*state)->src.seqhi + 1, (*state)->src.seqlo + 1,
-			    TH_ACK, (*state)->dst.max_win, 0, 0, 1,
-			    0, NULL, NULL);
-			(*state)->src.seqdiff = (*state)->dst.seqhi -
-			    (*state)->src.seqlo;
-			(*state)->dst.seqdiff = (*state)->src.seqhi -
-			    (*state)->dst.seqlo;
-			(*state)->src.seqhi = (*state)->src.seqlo +
-			    (*state)->dst.max_win;
-			(*state)->dst.seqhi = (*state)->dst.seqlo +
-			    (*state)->src.max_win;
-			(*state)->src.wscale = (*state)->dst.wscale = 0;
-			(*state)->src.state = (*state)->dst.state =
-			    TCPS_ESTABLISHED;
-			REASON_SET(reason, PFRES_SYNPROXY);
-			return (PF_SYNPROXY_DROP);
-		}
-	}
-
-	if (((th->th_flags & (TH_SYN|TH_ACK)) == TH_SYN) &&
-	    dst->state >= TCPS_FIN_WAIT_2 &&
-	    src->state >= TCPS_FIN_WAIT_2) {
-		if (pf_status.debug >= PF_DEBUG_MISC) {
-			printf("pf: state reuse ");
-			pf_print_state(*state);
-			pf_print_flags(th->th_flags);
-			printf("\n");
-		}
-		/* XXX make sure it's the same direction ?? */
-		(*state)->src.state = (*state)->dst.state = TCPS_CLOSED;
-		pf_unlink_state(*state);
-		*state = NULL;
-		return (PF_DROP);
-	}
 
 	if (src->wscale && dst->wscale && !(th->th_flags & TH_SYN)) {
 		sws = src->wscale & PF_WSCALE_MASK;
@@ -3815,7 +3691,7 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 			pf_change_a(&th->th_seq, &th->th_sum, htonl(seq +
 			    src->seqdiff), 0);
 			pf_change_a(&th->th_ack, &th->th_sum, htonl(ack), 0);
-			copyback = 1;
+			*copyback = 1;
 		} else {
 			ack = ntohl(th->th_ack);
 		}
@@ -3867,7 +3743,7 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 			pf_change_a(&th->th_seq, &th->th_sum, htonl(seq +
 			    src->seqdiff), 0);
 			pf_change_a(&th->th_ack, &th->th_sum, htonl(ack), 0);
-			copyback = 1;
+			*copyback = 1;
 		}
 		end = seq + pd->p_len;
 		if (th->th_flags & TH_SYN)
@@ -3913,7 +3789,7 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 	 */
 	if (dst->seqdiff && (th->th_off << 2) > sizeof(struct tcphdr)) {
 		if (pf_modulate_sack(m, off, pd, th, dst))
-			copyback = 1;
+			*copyback = 1;
 	}
 
 
@@ -3933,7 +3809,7 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 
 		if (dst->scrub || src->scrub) {
 			if (pf_normalize_tcp_stateful(m, off, pd, reason, th,
-			    *state, src, dst, &copyback))
+			    *state, src, dst, copyback))
 				return (PF_DROP);
 		}
 
@@ -4026,14 +3902,13 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 			    "pkts=%llu:%llu dir=%s,%s\n", seq, orig_seq, ack,
 			    pd->p_len, ackskew, (*state)->packets[0],
 			    (*state)->packets[1],
-			    direction == PF_IN ? "in" : "out",
-			    direction == (*state)->direction ?
-				"fwd" : "rev");
+			    pd->dir == PF_IN ? "in" : "out",
+			    pd->dir == (*state)->direction ? "fwd" : "rev");
 		}
 
 		if (dst->scrub || src->scrub) {
 			if (pf_normalize_tcp_stateful(m, off, pd, reason, th,
-			    *state, src, dst, &copyback))
+			    *state, src, dst, copyback))
 				return (PF_DROP);
 		}
 
@@ -4082,9 +3957,8 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 			    "pkts=%llu:%llu dir=%s,%s\n",
 			    seq, orig_seq, ack, pd->p_len, ackskew,
 			    (*state)->packets[0], (*state)->packets[1],
-			    direction == PF_IN ? "in" : "out",
-			    direction == (*state)->direction ?
-				"fwd" : "rev");
+			    pd->dir == PF_IN ? "in" : "out",
+			    pd->dir == (*state)->direction ? "fwd" : "rev");
 			printf("pf: State failure on: %c %c %c %c | %c %c\n",
 			    SEQ_GEQ(src->seqhi, end) ? ' ' : '1',
 			    SEQ_GEQ(seq, src->seqlo - (dst->max_win << dws)) ?
@@ -4098,8 +3972,147 @@ pf_test_state_tcp(struct pf_state **state, int direction, struct pfi_kif *kif,
 		return (PF_DROP);
 	}
 
-	/* Any packets which have gotten here are to be passed */
+	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)
+{
+	struct pf_state_key_cmp	 key;
+	struct tcphdr		*th = pd->hdr.tcp;
+	int			 copyback = 0;
+	struct pf_state_peer	*src, *dst;
+	struct pf_state_key	*sk;
+
+	key.af = pd->af;
+	key.proto = IPPROTO_TCP;
+	if (direction == PF_IN)	{	/* wire side, straight */
+		PF_ACPY(&key.addr[0], pd->src, key.af);
+		PF_ACPY(&key.addr[1], pd->dst, key.af);
+		key.port[0] = th->th_sport;
+		key.port[1] = th->th_dport;
+	} else {			/* stack side, reverse */
+		PF_ACPY(&key.addr[1], pd->src, key.af);
+		PF_ACPY(&key.addr[0], pd->dst, key.af);
+		key.port[1] = th->th_sport;
+		key.port[0] = th->th_dport;
+	}
+
+	STATE_LOOKUP(kif, &key, direction, *state);
+
+	if (direction == (*state)->direction) {
+		src = &(*state)->src;
+		dst = &(*state)->dst;
+	} else {
+		src = &(*state)->dst;
+		dst = &(*state)->src;
+	}
+
+	sk = (*state)->key[pd->didx];
 
+	if ((*state)->src.state == PF_TCPS_PROXY_SRC) {
+		if (direction != (*state)->direction) {
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_SYNPROXY_DROP);
+		}
+		if (th->th_flags & TH_SYN) {
+			if (ntohl(th->th_seq) != (*state)->src.seqlo) {
+				REASON_SET(reason, PFRES_SYNPROXY);
+				return (PF_DROP);
+			}
+			pf_send_tcp((*state)->rule.ptr, pd->af, pd->dst,
+			    pd->src, th->th_dport, th->th_sport,
+			    (*state)->src.seqhi, ntohl(th->th_seq) + 1,
+			    TH_SYN|TH_ACK, 0, (*state)->src.mss, 0, 1,
+			    0, NULL, NULL);
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_SYNPROXY_DROP);
+		} else if (!(th->th_flags & TH_ACK) ||
+		    (ntohl(th->th_ack) != (*state)->src.seqhi + 1) ||
+		    (ntohl(th->th_seq) != (*state)->src.seqlo + 1)) {
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_DROP);
+		} else if ((*state)->src_node != NULL &&
+		    pf_src_connlimit(state)) {
+			REASON_SET(reason, PFRES_SRCLIMIT);
+			return (PF_DROP);
+		} else
+			(*state)->src.state = PF_TCPS_PROXY_DST;
+	}
+	if ((*state)->src.state == PF_TCPS_PROXY_DST) {
+		if (direction == (*state)->direction) {
+			if (((th->th_flags & (TH_SYN|TH_ACK)) != TH_ACK) ||
+			    (ntohl(th->th_ack) != (*state)->src.seqhi + 1) ||
+			    (ntohl(th->th_seq) != (*state)->src.seqlo + 1)) {
+				REASON_SET(reason, PFRES_SYNPROXY);
+				return (PF_DROP);
+			}
+			(*state)->src.max_win = MAX(ntohs(th->th_win), 1);
+			if ((*state)->dst.seqhi == 1)
+				(*state)->dst.seqhi = htonl(arc4random());
+			pf_send_tcp((*state)->rule.ptr, pd->af,
+			    &sk->addr[pd->sidx], &sk->addr[pd->didx],
+			    sk->port[pd->sidx], sk->port[pd->didx],
+			    (*state)->dst.seqhi, 0, TH_SYN, 0,
+			    (*state)->src.mss, 0, 0, (*state)->tag, NULL, NULL);
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_SYNPROXY_DROP);
+		} else if (((th->th_flags & (TH_SYN|TH_ACK)) !=
+		    (TH_SYN|TH_ACK)) ||
+		    (ntohl(th->th_ack) != (*state)->dst.seqhi + 1)) {
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_DROP);
+		} else {
+			(*state)->dst.max_win = MAX(ntohs(th->th_win), 1);
+			(*state)->dst.seqlo = ntohl(th->th_seq);
+			pf_send_tcp((*state)->rule.ptr, pd->af, pd->dst,
+			    pd->src, th->th_dport, th->th_sport,
+			    ntohl(th->th_ack), ntohl(th->th_seq) + 1,
+			    TH_ACK, (*state)->src.max_win, 0, 0, 0,
+			    (*state)->tag, NULL, NULL);
+			pf_send_tcp((*state)->rule.ptr, pd->af,
+			    &sk->addr[pd->sidx], &sk->addr[pd->didx],
+			    sk->port[pd->sidx], sk->port[pd->didx],
+			    (*state)->src.seqhi + 1, (*state)->src.seqlo + 1,
+			    TH_ACK, (*state)->dst.max_win, 0, 0, 1,
+			    0, NULL, NULL);
+			(*state)->src.seqdiff = (*state)->dst.seqhi -
+			    (*state)->src.seqlo;
+			(*state)->dst.seqdiff = (*state)->src.seqhi -
+			    (*state)->dst.seqlo;
+			(*state)->src.seqhi = (*state)->src.seqlo +
+			    (*state)->dst.max_win;
+			(*state)->dst.seqhi = (*state)->dst.seqlo +
+			    (*state)->src.max_win;
+			(*state)->src.wscale = (*state)->dst.wscale = 0;
+			(*state)->src.state = (*state)->dst.state =
+			    TCPS_ESTABLISHED;
+			REASON_SET(reason, PFRES_SYNPROXY);
+			return (PF_SYNPROXY_DROP);
+		}
+	}
+
+	if (((th->th_flags & (TH_SYN|TH_ACK)) == TH_SYN) &&
+	    dst->state >= TCPS_FIN_WAIT_2 &&
+	    src->state >= TCPS_FIN_WAIT_2) {
+		if (pf_status.debug >= PF_DEBUG_MISC) {
+			printf("pf: state reuse ");
+			pf_print_state(*state);
+			pf_print_flags(th->th_flags);
+			printf("\n");
+		}
+		/* XXX make sure it's the same direction ?? */
+		(*state)->src.state = (*state)->dst.state = TCPS_CLOSED;
+		pf_unlink_state(*state);
+		*state = NULL;
+		return (PF_DROP);
+	}
+
+	if (pf_tcp_seqtrack_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]) {