divert: consume PF_TAG_DIVERTED after passthrough (BSD ip_input role); divert layer owns its own skb ref; gate uses pfput path

module/pfsrc/divert_sock.c

@@ -166,13 +166,19 @@ divert_packet(struct mbuf *m, int dir, u_int16_t divert_port)
 	{
 		struct pf_divert *dv = pf_find_divert(m);
 
-		if (dv)
+		if (dv) {
 			type = dv->type;
+			if (divert_port == 0)
+				divert_port = dv->port;
+		}
 	}
 	skb = m_to_skb(m);
-	m->skb = NULL;		/* ownership moves into the divert layer */
+	if (skb)
+		skb_get(skb);	/* divert layer's own reference */
+	m->skb = NULL;
 	m_freem(m);
-	pfk_divert_queue(skb, dir, type, divert_port);
+	if (skb)
+		pfk_divert_queue(skb, dir, type, divert_port);
 }
 
 void

module/pfsrc/pfk_hooks.c

@@ -22,6 +22,7 @@
 #include <net/pfvar_priv.h>
 
 extern int pf_test(sa_family_t, int, struct pfk_ifnet *, struct mbuf **);
+extern void divert_packet(struct mbuf *, int, u_int16_t);
 extern struct workqueue_struct *pfk_netisr_wq;
 
 /* PFLINUX: netisr work item — carries ownership of one sk_buff */
@@ -91,6 +92,17 @@ pfk_pkt_work(struct work_struct *w)
 	 * and packet walk run concurrently from here on — documented. */
 	action = pf_test(pk->af, pk->dir, pk->ifp, &m);
 
+	/* PF_IN rules with `divert-to` only TAG the packet (BSD
+	 * netinet/ip_input.c delivers tagged packets to the divert socket);
+	 * do that here.  divert_packet() consumes the mbuf wrapper and holds
+	 * its own skb reference, so our wrapper pointer becomes invalid. */
+	if (action == PF_PASS && m != NULL &&
+	    (m->m_pkthdr.pf.flags & PF_TAG_DIVERTED)) {
+		m->m_pkthdr.pf.flags &= ~PF_TAG_DIVERTED;
+		divert_packet(m, pk->dir, 0);
+		m = NULL;
+	}
+
 	if (m == m0) {
 		/* same buffer, possibly rewritten in place: our wrapper
 		 * held one extra skb reference — release it */

tests/vm/11-divert.sh

@@ -16,8 +16,8 @@ FAILED=0
 
 pf0 "insmod /tmp/pf.ko 2>/dev/null || insmod /opt/pf/pf.ko; true"
 pf0 '/opt/pf/pfctl -e; /opt/pf/pfctl -f /dev/null' >/dev/null
-pfput ../../tools/out/pdivert /opt/pf/pdivert || bad "pdivert deploy"
-pf0 'chmod +x /opt/pf/pdivert' >/dev/null
+PDIV=$(pfput ../../tools/out/pdivert) || bad "pdivert deploy"
+pf0 "chmod +x $PDIV" >/dev/null
 
 cat > /tmp/g11.conf <<C
 pass in quick proto icmp from $CLI_IP to $PFLAN divert-to "$PFLAN" port $PORT keep state
@@ -32,7 +32,7 @@ pf0 "/opt/pf/pfctl -s info" | grep -qi noport || true   # informational
 # (b) start pdivert, capture reply bytes on cli
 cli 'tcpdump -ni eth0 -e -c 4 -X icmp > /tmp/td.txt 2>&1 &' 2>/dev/null
 sleep 1
-pf0 "setsid /opt/pf/pdivert -p $PORT -q > /tmp/pdiv.log 2>&1 & echo STARTED" | grep -q STARTED || { bad "pdivert start"; finish; }
+pf0 "setsid ${PDIV:-/tmp/pdivert} -p $PORT -q > /tmp/pdiv.log 2>&1 & echo STARTED" | grep -q STARTED || { bad "pdivert start"; finish; }
 sleep 1
 cli "ping -c 2 -W 2 $PFLAN >/dev/null 2>&1" && ok "ping passes through divert+rewrite" || bad "ping with listener"
 sleep 2