Add some documenting NET_EPOCH_ASSERTs.

sys/netinet/tcp_subr.c

@@ -1394,6 +1394,7 @@ tcp_respond(struct tcpcb *tp, void *ipgen, struct tcphdr *th, struct mbuf *m,
 	bool incl_opts;
 
 	KASSERT(tp != NULL || m != NULL, ("tcp_respond: tp and m both NULL"));
+	NET_EPOCH_ASSERT();
 
 #ifdef INET6
 	isipv6 = ((struct ip *)ipgen)->ip_v == (IPV6_VERSION >> 4);

sys/netinet/tcp_syncache.c

@@ -1751,6 +1751,9 @@ syncache_respond(struct syncache *sc, const struct mbuf *m0, int flags)
 #ifdef INET6
 	struct ip6_hdr *ip6 = NULL;
 #endif
+
+	NET_EPOCH_ASSERT();
+
 	hlen =
 #ifdef INET6
 	       (sc->sc_inc.inc_flags & INC_ISIPV6) ? sizeof(struct ip6_hdr) :

sys/netinet6/mld6.c

@@ -3095,6 +3095,7 @@ mld_dispatch_packet(struct mbuf *m)
 	uint32_t		 ifindex;
 
 	CTR2(KTR_MLD, "%s: transmit %p", __func__, m);
+	NET_EPOCH_ASSERT();
 
 	/*
 	 * Set VNET image pointer from enqueued mbuf chain