X-Git-Url: https://git.tcpdump.org/libpcap/blobdiff_plain/48e0c09775549a4e3af7b43cf66d2a108bb16d14..8f99c57221636f18f73ac026c9f9f7a9c9594dce:/gencode.c

diff --git a/gencode.c b/gencode.c
index 48b509b0..eed4863c 100644
--- a/gencode.c
+++ b/gencode.c
@@ -679,11 +679,10 @@ static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
     struct in6_addr *, int, u_int, u_int);
 #endif
 static struct block *gen_ahostop(compiler_state_t *, const uint8_t, int);
-static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
-static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
-static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
 static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
-static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
+static unsigned char is_mac48_linktype(const int);
+static struct block *gen_mac48host(compiler_state_t *, const u_char *,
+    const u_char, const char *);
 static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
 static struct block *gen_mpls_linktype(compiler_state_t *, bpf_u_int32);
 static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
@@ -696,23 +695,23 @@ static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
 static struct block *gen_gateway(compiler_state_t *, const u_char *,
     struct addrinfo *, int);
 #endif
+static struct block *gen_ip_proto(compiler_state_t *, const uint8_t);
+static struct block *gen_ip6_proto(compiler_state_t *, const uint8_t);
 static struct block *gen_ipfrag(compiler_state_t *);
-static struct block *gen_portatom(compiler_state_t *, int, bpf_u_int32);
-static struct block *gen_portrangeatom(compiler_state_t *, u_int, bpf_u_int32,
-    bpf_u_int32);
-static struct block *gen_portatom6(compiler_state_t *, int, bpf_u_int32);
-static struct block *gen_portrangeatom6(compiler_state_t *, u_int, bpf_u_int32,
-    bpf_u_int32);
-static struct block *gen_portop(compiler_state_t *, u_int, u_int, int);
-static struct block *gen_port(compiler_state_t *, u_int, int, int);
-static struct block *gen_portrangeop(compiler_state_t *, u_int, u_int,
-    bpf_u_int32, int);
-static struct block *gen_portrange(compiler_state_t *, u_int, u_int, int, int);
-struct block *gen_portop6(compiler_state_t *, u_int, u_int, int);
-static struct block *gen_port6(compiler_state_t *, u_int, int, int);
-static struct block *gen_portrangeop6(compiler_state_t *, u_int, u_int,
-    bpf_u_int32, int);
-static struct block *gen_portrange6(compiler_state_t *, u_int, u_int, int, int);
+static struct block *gen_portatom(compiler_state_t *, int, uint16_t);
+static struct block *gen_portrangeatom(compiler_state_t *, u_int, uint16_t,
+    uint16_t);
+static struct block *gen_portatom6(compiler_state_t *, int, uint16_t);
+static struct block *gen_portrangeatom6(compiler_state_t *, u_int, uint16_t,
+    uint16_t);
+static struct block *gen_port(compiler_state_t *, uint16_t, int, int);
+static struct block *gen_port_common(compiler_state_t *, int, struct block *);
+static struct block *gen_portrange(compiler_state_t *, uint16_t, uint16_t,
+    int, int);
+static struct block *gen_port6(compiler_state_t *, uint16_t, int, int);
+static struct block *gen_port6_common(compiler_state_t *, int, struct block *);
+static struct block *gen_portrange6(compiler_state_t *, uint16_t, uint16_t,
+    int, int);
 static int lookup_proto(compiler_state_t *, const char *, int);
 #if !defined(NO_PROTOCHAIN)
 static struct block *gen_protochain(compiler_state_t *, bpf_u_int32, int);
@@ -727,7 +726,10 @@ static struct block *gen_encap_ll_check(compiler_state_t *cstate);
 static struct block *gen_atmfield_code_internal(compiler_state_t *, int,
     bpf_u_int32, int, int);
 static struct block *gen_atmtype_llc(compiler_state_t *);
-static struct block *gen_msg_abbrev(compiler_state_t *, int type);
+static struct block *gen_msg_abbrev(compiler_state_t *, const uint8_t);
+static struct block *gen_atm_prototype(compiler_state_t *, const uint8_t);
+static struct block *gen_atm_vpi(compiler_state_t *, const uint8_t);
+static struct block *gen_atm_vci(compiler_state_t *, const uint16_t);
 
 static void
 initchunks(compiler_state_t *cstate)
@@ -975,16 +977,8 @@ atmkw(const unsigned id)
 		[A_OAM] = "oam",
 		[A_OAMF4] = "oamf4",
 		[A_LANE] = "lane",
-		// no keyword for A_SETUP
-		// no keyword for A_CALLPROCEED
-		// no keyword for A_CONNECT
-		// no keyword for A_CONNECTACK
-		// no keyword for A_RELEASE
-		// no keyword for A_RELEASE_DONE
 		[A_VPI] = "vpi",
 		[A_VCI] = "vci",
-		// no keyword for A_PROTOTYPE
-		// no keyword for A_MSGTYPE
 		[A_CONNECTMSG] = "connectmsg",
 		[A_METACONNECT] = "metaconnect",
 	};
@@ -1072,6 +1066,7 @@ assert_maxval(compiler_state_t *cstate, const char *name,
 
 #define ERRSTR_802_11_ONLY_KW "'%s' is valid for 802.11 syntax only"
 #define ERRSTR_INVALID_QUAL "'%s' is not a valid qualifier for '%s'"
+#define ERRSTR_UNKNOWN_MAC48HOST "unknown Ethernet-like host '%s'"
 
 // Validate a port/portrange proto qualifier and map to an IP protocol number.
 static int
@@ -1462,6 +1457,19 @@ static struct block *
 gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
     u_int size, bpf_u_int32 v, bpf_u_int32 mask)
 {
+	/*
+	 * For any A: if mask == 0, it means A & mask == 0, so the result is
+	 * true iff v == 0.  In this case ideally the caller should have
+	 * skipped this invocation and have fewer statement blocks to juggle.
+	 * If the caller could have skipped, but has not, produce a block with
+	 * fewer statements.
+	 *
+	 * This could be done in gen_ncmp() in a more generic way, but this
+	 * function is the only code path that can have mask == 0.
+	 */
+	if (mask == 0)
+		return v ? gen_false(cstate) : gen_true(cstate);
+
 	return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
 }
 
@@ -3656,7 +3664,7 @@ gen_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto)
 		 *
 		 * Check for LLC encapsulation and then check the protocol.
 		 */
-		b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
+		b0 = gen_atm_prototype(cstate, PT_LLC);
 		b1 = gen_llc_linktype(cstate, ll_proto);
 		gen_and(b0, b1);
 		return b1;
@@ -4462,139 +4470,24 @@ gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
 	/* this order is important */
 	memcpy(a, addr, sizeof(a));
 	memcpy(m, mask, sizeof(m));
-	b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
-	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
-	gen_and(b0, b1);
-	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
-	gen_and(b0, b1);
-	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
-	gen_and(b0, b1);
-	return b1;
-}
-#endif
-
-static struct block *
-gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
-{
-	register struct block *b0, *b1;
-
-	switch (dir) {
-	case Q_SRC:
-		return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
-
-	case Q_DST:
-		return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
-
-	case Q_AND:
-		b0 = gen_ehostop(cstate, eaddr, Q_SRC);
-		b1 = gen_ehostop(cstate, eaddr, Q_DST);
-		gen_and(b0, b1);
-		return b1;
-
-	case Q_DEFAULT:
-	case Q_OR:
-		b0 = gen_ehostop(cstate, eaddr, Q_SRC);
-		b1 = gen_ehostop(cstate, eaddr, Q_DST);
-		gen_or(b0, b1);
-		return b1;
-
-	case Q_ADDR1:
-	case Q_ADDR2:
-	case Q_ADDR3:
-	case Q_ADDR4:
-	case Q_RA:
-	case Q_TA:
-		bpf_error(cstate, ERRSTR_802_11_ONLY_KW, dqkw(dir));
-		/*NOTREACHED*/
-	}
-	abort();
-	/*NOTREACHED*/
-}
-
-/*
- * Like gen_ehostop, but for DLT_FDDI
- */
-static struct block *
-gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
-{
-	struct block *b0, *b1;
-
-	switch (dir) {
-	case Q_SRC:
-		return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
-
-	case Q_DST:
-		return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
-
-	case Q_AND:
-		b0 = gen_fhostop(cstate, eaddr, Q_SRC);
-		b1 = gen_fhostop(cstate, eaddr, Q_DST);
-		gen_and(b0, b1);
-		return b1;
-
-	case Q_DEFAULT:
-	case Q_OR:
-		b0 = gen_fhostop(cstate, eaddr, Q_SRC);
-		b1 = gen_fhostop(cstate, eaddr, Q_DST);
-		gen_or(b0, b1);
-		return b1;
-
-	case Q_ADDR1:
-	case Q_ADDR2:
-	case Q_ADDR3:
-	case Q_ADDR4:
-	case Q_RA:
-	case Q_TA:
-		bpf_error(cstate, ERRSTR_802_11_ONLY_KW, dqkw(dir));
-		/*NOTREACHED*/
-	}
-	abort();
-	/*NOTREACHED*/
-}
-
-/*
- * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
- */
-static struct block *
-gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
-{
-	register struct block *b0, *b1;
-
-	switch (dir) {
-	case Q_SRC:
-		return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
-
-	case Q_DST:
-		return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
-
-	case Q_AND:
-		b0 = gen_thostop(cstate, eaddr, Q_SRC);
-		b1 = gen_thostop(cstate, eaddr, Q_DST);
-		gen_and(b0, b1);
-		return b1;
-
-	case Q_DEFAULT:
-	case Q_OR:
-		b0 = gen_thostop(cstate, eaddr, Q_SRC);
-		b1 = gen_thostop(cstate, eaddr, Q_DST);
-		gen_or(b0, b1);
-		return b1;
-
-	case Q_ADDR1:
-	case Q_ADDR2:
-	case Q_ADDR3:
-	case Q_ADDR4:
-	case Q_RA:
-	case Q_TA:
-		bpf_error(cstate, ERRSTR_802_11_ONLY_KW, dqkw(dir));
-		/*NOTREACHED*/
+	b1 = NULL;
+	for (int i = 3; i >= 0; i--) {
+		// Same as the Q_IP case in gen_host().
+		if (m[i] == 0 && a[i] == 0)
+			continue;
+		b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4 * i, BPF_W,
+		    ntohl(a[i]), ntohl(m[i]));
+		if (b1)
+			gen_and(b0, b1);
+		else
+			b1 = b0;
 	}
-	abort();
-	/*NOTREACHED*/
+	return b1 ? b1 : gen_true(cstate);
 }
+#endif
 
 /*
- * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
+ * Like gen_mac48host(), but for DLT_IEEE802_11 (802.11 wireless LAN) and
  * various 802.11 + radio headers.
  */
 static struct block *
@@ -4974,49 +4867,6 @@ gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
 	/*NOTREACHED*/
 }
 
-/*
- * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
- * (We assume that the addresses are IEEE 48-bit MAC addresses,
- * as the RFC states.)
- */
-static struct block *
-gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
-{
-	register struct block *b0, *b1;
-
-	switch (dir) {
-	case Q_SRC:
-		return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
-
-	case Q_DST:
-		return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
-
-	case Q_AND:
-		b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
-		b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
-		gen_and(b0, b1);
-		return b1;
-
-	case Q_DEFAULT:
-	case Q_OR:
-		b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
-		b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
-		gen_or(b0, b1);
-		return b1;
-
-	case Q_ADDR1:
-	case Q_ADDR2:
-	case Q_ADDR3:
-	case Q_ADDR4:
-	case Q_RA:
-	case Q_TA:
-		bpf_error(cstate, ERRSTR_802_11_ONLY_KW, dqkw(dir));
-		/*NOTREACHED*/
-	}
-	abort();
-	/*NOTREACHED*/
-}
-
 /*
  * This is quite tricky because there may be pad bytes in front of the
  * DECNET header, and then there are two possible data packet formats that
@@ -5172,16 +5022,16 @@ gen_mpls_linktype(compiler_state_t *cstate, bpf_u_int32 ll_proto)
 	case ETHERTYPE_IPV6:
 		/* match the bottom-of-stack bit */
 		b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
-		/* match the IPv4 version number */
+		/* match the IPv6 version number */
 		b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
 		gen_and(b0, b1);
 		return b1;
 
- default:
-	 /* FIXME add other L3 proto IDs */
-	 bpf_error(cstate, "unsupported protocol over mpls");
-	 /*NOTREACHED*/
- }
+	default:
+		/* FIXME add other L3 proto IDs */
+		bpf_error(cstate, "unsupported protocol over mpls");
+		/*NOTREACHED*/
+	}
 }
 
 static struct block *
@@ -5212,18 +5062,33 @@ gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
 
 	case Q_IP:
 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
+		/*
+		 * Belt and braces: if other code works correctly, any host
+		 * bits are clear and mask == 0 means addr == 0.  In this case
+		 * the call to gen_hostop() would produce an "always true"
+		 * instruction block and ANDing it with the link type check
+		 * would be a no-op.
+		 */
+		if (mask == 0 && addr == 0)
+			return b0;
 		b1 = gen_hostop(cstate, addr, mask, dir, 12, 16);
 		gen_and(b0, b1);
 		return b1;
 
 	case Q_RARP:
 		b0 = gen_linktype(cstate, ETHERTYPE_REVARP);
+		// Same as for Q_IP above.
+		if (mask == 0 && addr == 0)
+			return b0;
 		b1 = gen_hostop(cstate, addr, mask, dir, 14, 24);
 		gen_and(b0, b1);
 		return b1;
 
 	case Q_ARP:
 		b0 = gen_linktype(cstate, ETHERTYPE_ARP);
+		// Same as for Q_IP above.
+		if (mask == 0 && addr == 0)
+			return b0;
 		b1 = gen_hostop(cstate, addr, mask, dir, 14, 24);
 		gen_and(b0, b1);
 		return b1;
@@ -5292,6 +5157,12 @@ gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
 	case Q_DEFAULT:
 	case Q_IPV6:
 		b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
+		// Same as the Q_IP case in gen_host().
+		if (
+			! memcmp(mask, &in6addr_any, sizeof(struct in6_addr)) &&
+			! memcmp(addr, &in6addr_any, sizeof(struct in6_addr))
+		)
+			return b0;
 		b1 = gen_hostop6(cstate, addr, mask, dir, 8, 24);
 		gen_and(b0, b1);
 		return b1;
@@ -5345,6 +5216,104 @@ gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
 }
 #endif
 
+static unsigned char
+is_mac48_linktype(const int linktype)
+{
+	switch (linktype) {
+	case DLT_EN10MB:
+	case DLT_FDDI:
+	case DLT_IEEE802:
+	case DLT_IEEE802_11:
+	case DLT_IEEE802_11_RADIO:
+	case DLT_IEEE802_11_RADIO_AVS:
+	case DLT_IP_OVER_FC:
+	case DLT_NETANALYZER:
+	case DLT_NETANALYZER_TRANSPARENT:
+	case DLT_PPI:
+	case DLT_PRISM_HEADER:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static struct block *
+gen_mac48host(compiler_state_t *cstate, const u_char *eaddr, const u_char dir,
+    const char *keyword)
+{
+	struct block *b1 = NULL;
+	u_int src_off, dst_off;
+
+	switch (cstate->linktype) {
+	case DLT_EN10MB:
+	case DLT_NETANALYZER:
+	case DLT_NETANALYZER_TRANSPARENT:
+		b1 = gen_prevlinkhdr_check(cstate);
+		src_off = 6;
+		dst_off = 0;
+		break;
+	case DLT_FDDI:
+		src_off = 6 + 1 + cstate->pcap_fddipad;
+		dst_off = 0 + 1 + cstate->pcap_fddipad;
+		break;
+	case DLT_IEEE802:
+		src_off = 8;
+		dst_off = 2;
+		break;
+	case DLT_IEEE802_11:
+	case DLT_PRISM_HEADER:
+	case DLT_IEEE802_11_RADIO_AVS:
+	case DLT_IEEE802_11_RADIO:
+	case DLT_PPI:
+		return gen_wlanhostop(cstate, eaddr, dir);
+	case DLT_IP_OVER_FC:
+		/*
+		 * Assume that the addresses are IEEE 48-bit MAC addresses,
+		 * as RFC 2625 states.
+		 */
+		src_off = 10;
+		dst_off = 2;
+		break;
+	case DLT_SUNATM:
+		/*
+		 * This is LLC-multiplexed traffic; if it were
+		 * LANE, cstate->linktype would have been set to
+		 * DLT_EN10MB.
+		 */
+		 /* FALLTHROUGH */
+	default:
+		fail_kw_on_dlt(cstate, keyword);
+	}
+
+	struct block *b0, *tmp;
+
+	switch (dir) {
+	case Q_SRC:
+		b0 = gen_bcmp(cstate, OR_LINKHDR, src_off, 6, eaddr);
+		break;
+	case Q_DST:
+		b0 = gen_bcmp(cstate, OR_LINKHDR, dst_off, 6, eaddr);
+		break;
+	case Q_AND:
+		tmp = gen_bcmp(cstate, OR_LINKHDR, src_off, 6, eaddr);
+		b0 = gen_bcmp(cstate, OR_LINKHDR, dst_off, 6, eaddr);
+		gen_and(tmp, b0);
+		break;
+	case Q_DEFAULT:
+	case Q_OR:
+		tmp = gen_bcmp(cstate, OR_LINKHDR, src_off, 6, eaddr);
+		b0 = gen_bcmp(cstate, OR_LINKHDR, dst_off, 6, eaddr);
+		gen_or(tmp, b0);
+		break;
+	default:
+		bpf_error(cstate, ERRSTR_802_11_ONLY_KW, dqkw(dir));
+	}
+
+	if (b1 != NULL)
+		gen_and(b1, b0);
+	return b0;
+}
+
 #ifndef INET6
 /*
  * This primitive is non-directional by design, so the grammar does not allow
@@ -5363,42 +5332,7 @@ gen_gateway(compiler_state_t *cstate, const u_char *eaddr,
 	case Q_IP:
 	case Q_ARP:
 	case Q_RARP:
-		switch (cstate->linktype) {
-		case DLT_EN10MB:
-		case DLT_NETANALYZER:
-		case DLT_NETANALYZER_TRANSPARENT:
-			b1 = gen_prevlinkhdr_check(cstate);
-			b0 = gen_ehostop(cstate, eaddr, Q_OR);
-			if (b1 != NULL)
-				gen_and(b1, b0);
-			break;
-		case DLT_FDDI:
-			b0 = gen_fhostop(cstate, eaddr, Q_OR);
-			break;
-		case DLT_IEEE802:
-			b0 = gen_thostop(cstate, eaddr, Q_OR);
-			break;
-		case DLT_IEEE802_11:
-		case DLT_PRISM_HEADER:
-		case DLT_IEEE802_11_RADIO_AVS:
-		case DLT_IEEE802_11_RADIO:
-		case DLT_PPI:
-			b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
-			break;
-		case DLT_IP_OVER_FC:
-			b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
-			break;
-		case DLT_SUNATM:
-			/*
-			 * This is LLC-multiplexed traffic; if it were
-			 * LANE, cstate->linktype would have been set to
-			 * DLT_EN10MB.
-			 */
-			 /* FALLTHROUGH */
-		default:
-			bpf_error(cstate,
-			    "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
-		}
+		b0 = gen_mac48host(cstate, eaddr, Q_OR, "gateway");
 		b1 = NULL;
 		for (ai = alist; ai != NULL; ai = ai->ai_next) {
 			/*
@@ -5662,6 +5596,18 @@ gen_proto_abbrev(compiler_state_t *cstate, int proto)
 	return gen_proto_abbrev_internal(cstate, proto);
 }
 
+static struct block *
+gen_ip_proto(compiler_state_t *cstate, const uint8_t proto)
+{
+	return gen_cmp(cstate, OR_LINKPL, 9, BPF_B, proto);
+}
+
+static struct block *
+gen_ip6_proto(compiler_state_t *cstate, const uint8_t proto)
+{
+	return gen_cmp(cstate, OR_LINKPL, 6, BPF_B, proto);
+}
+
 static struct block *
 gen_ipfrag(compiler_state_t *cstate)
 {
@@ -5682,26 +5628,21 @@ gen_ipfrag(compiler_state_t *cstate)
  * headers).
  */
 static struct block *
-gen_portatom(compiler_state_t *cstate, int off, bpf_u_int32 v)
+gen_portatom(compiler_state_t *cstate, int off, uint16_t v)
 {
 	return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
 }
 
 static struct block *
-gen_portatom6(compiler_state_t *cstate, int off, bpf_u_int32 v)
+gen_portatom6(compiler_state_t *cstate, int off, uint16_t v)
 {
 	return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
 }
 
 static struct block *
-gen_portop(compiler_state_t *cstate, u_int port, u_int proto, int dir)
+gen_port(compiler_state_t *cstate, uint16_t port, int proto, int dir)
 {
-	struct block *b0, *b1, *tmp;
-
-	/* ip proto 'proto' and not a fragment other than the first fragment */
-	tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, proto);
-	b0 = gen_ipfrag(cstate);
-	gen_and(tmp, b0);
+	struct block *b1, *tmp;
 
 	switch (dir) {
 	case Q_SRC:
@@ -5738,15 +5679,14 @@ gen_portop(compiler_state_t *cstate, u_int port, u_int proto, int dir)
 		abort();
 		/*NOTREACHED*/
 	}
-	gen_and(b0, b1);
 
-	return b1;
+	return gen_port_common(cstate, proto, b1);
 }
 
 static struct block *
-gen_port(compiler_state_t *cstate, u_int port, int ip_proto, int dir)
+gen_port_common(compiler_state_t *cstate, int proto, struct block *b1)
 {
-	struct block *b0, *b1, *tmp;
+	struct block *b0, *tmp;
 
 	/*
 	 * ether proto ip
@@ -5764,39 +5704,47 @@ gen_port(compiler_state_t *cstate, u_int port, int ip_proto, int dir)
 	 * encapsulation with LLCSAP_IP.
 	 *
 	 * So we always check for ETHERTYPE_IP.
+	 *
+	 * At the time of this writing all three L4 protocols the "port" and
+	 * "portrange" primitives support (TCP, UDP and SCTP) have the source
+	 * and the destination ports identically encoded in the transport
+	 * protocol header.  So without a proto qualifier the only difference
+	 * between the implemented cases is the protocol number and all other
+	 * checks need to be made exactly once.
+	 *
+	 * If the expression syntax in future starts to support ports for
+	 * another L4 protocol that has unsigned integer ports encoded using a
+	 * different size and/or offset, this will require a different code.
 	 */
-	b0 = gen_linktype(cstate, ETHERTYPE_IP);
-
-	switch (ip_proto) {
+	switch (proto) {
 	case IPPROTO_UDP:
 	case IPPROTO_TCP:
 	case IPPROTO_SCTP:
-		b1 = gen_portop(cstate, port, (u_int)ip_proto, dir);
+		tmp = gen_ip_proto(cstate, (uint8_t)proto);
 		break;
 
 	case PROTO_UNDEF:
-		tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
-		b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
-		gen_or(tmp, b1);
-		tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
-		gen_or(tmp, b1);
+		tmp = gen_ip_proto(cstate, IPPROTO_UDP);
+		gen_or(gen_ip_proto(cstate, IPPROTO_TCP), tmp);
+		gen_or(gen_ip_proto(cstate, IPPROTO_SCTP), tmp);
 		break;
 
 	default:
 		abort();
 	}
+	// Not a fragment other than the first fragment.
+	b0 = gen_ipfrag(cstate);
+	gen_and(tmp, b0);
 	gen_and(b0, b1);
+	// "link proto \ip"
+	gen_and(gen_linktype(cstate, ETHERTYPE_IP), b1);
 	return b1;
 }
 
-struct block *
-gen_portop6(compiler_state_t *cstate, u_int port, u_int proto, int dir)
+static struct block *
+gen_port6(compiler_state_t *cstate, uint16_t port, int proto, int dir)
 {
-	struct block *b0, *b1, *tmp;
-
-	/* ip6 proto 'proto' */
-	/* XXX - catch the first fragment of a fragmented packet? */
-	b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, proto);
+	struct block *b1, *tmp;
 
 	switch (dir) {
 	case Q_SRC:
@@ -5823,45 +5771,44 @@ gen_portop6(compiler_state_t *cstate, u_int port, u_int proto, int dir)
 	default:
 		abort();
 	}
-	gen_and(b0, b1);
 
-	return b1;
+	return gen_port6_common(cstate, proto, b1);
 }
 
 static struct block *
-gen_port6(compiler_state_t *cstate, u_int port, int ip_proto, int dir)
+gen_port6_common(compiler_state_t *cstate, int proto, struct block *b1)
 {
-	struct block *b0, *b1, *tmp;
-
-	/* link proto ip6 */
-	b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
+	struct block *tmp;
 
-	switch (ip_proto) {
+	// "ip6 proto 'ip_proto'"
+	switch (proto) {
 	case IPPROTO_UDP:
 	case IPPROTO_TCP:
 	case IPPROTO_SCTP:
-		b1 = gen_portop6(cstate, port, (u_int)ip_proto, dir);
+		tmp = gen_ip6_proto(cstate, (uint8_t)proto);
 		break;
 
 	case PROTO_UNDEF:
-		tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
-		b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
-		gen_or(tmp, b1);
-		tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
-		gen_or(tmp, b1);
+		// Same as in gen_port_common().
+		tmp = gen_ip6_proto(cstate, IPPROTO_UDP);
+		gen_or(gen_ip6_proto(cstate, IPPROTO_TCP), tmp);
+		gen_or(gen_ip6_proto(cstate, IPPROTO_SCTP), tmp);
 		break;
 
 	default:
 		abort();
 	}
-	gen_and(b0, b1);
+	// XXX - catch the first fragment of a fragmented packet?
+	gen_and(tmp, b1);
+	// "link proto \ip6"
+	gen_and(gen_linktype(cstate, ETHERTYPE_IPV6), b1);
 	return b1;
 }
 
 /* gen_portrange code */
 static struct block *
-gen_portrangeatom(compiler_state_t *cstate, u_int off, bpf_u_int32 v1,
-    bpf_u_int32 v2)
+gen_portrangeatom(compiler_state_t *cstate, u_int off, uint16_t v1,
+    uint16_t v2)
 {
 	if (v1 == v2)
 		return gen_portatom(cstate, off, v1);
@@ -5877,15 +5824,10 @@ gen_portrangeatom(compiler_state_t *cstate, u_int off, bpf_u_int32 v1,
 }
 
 static struct block *
-gen_portrangeop(compiler_state_t *cstate, u_int port1, u_int port2,
-    bpf_u_int32 proto, int dir)
+gen_portrange(compiler_state_t *cstate, uint16_t port1, uint16_t port2,
+    int proto, int dir)
 {
-	struct block *b0, *b1, *tmp;
-
-	/* ip proto 'proto' and not a fragment other than the first fragment */
-	tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, proto);
-	b0 = gen_ipfrag(cstate);
-	gen_and(tmp, b0);
+	struct block *b1, *tmp;
 
 	switch (dir) {
 	case Q_SRC:
@@ -5922,46 +5864,13 @@ gen_portrangeop(compiler_state_t *cstate, u_int port1, u_int port2,
 		abort();
 		/*NOTREACHED*/
 	}
-	gen_and(b0, b1);
 
-	return b1;
+	return gen_port_common(cstate, proto, b1);
 }
 
 static struct block *
-gen_portrange(compiler_state_t *cstate, u_int port1, u_int port2, int ip_proto,
-    int dir)
-{
-	struct block *b0, *b1, *tmp;
-
-	/* link proto ip */
-	b0 = gen_linktype(cstate, ETHERTYPE_IP);
-
-	switch (ip_proto) {
-	case IPPROTO_UDP:
-	case IPPROTO_TCP:
-	case IPPROTO_SCTP:
-		b1 = gen_portrangeop(cstate, port1, port2, (bpf_u_int32)ip_proto,
-		    dir);
-		break;
-
-	case PROTO_UNDEF:
-		tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
-		b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
-		gen_or(tmp, b1);
-		tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
-		gen_or(tmp, b1);
-		break;
-
-	default:
-		abort();
-	}
-	gen_and(b0, b1);
-	return b1;
-}
-
-static struct block *
-gen_portrangeatom6(compiler_state_t *cstate, u_int off, bpf_u_int32 v1,
-    bpf_u_int32 v2)
+gen_portrangeatom6(compiler_state_t *cstate, u_int off, uint16_t v1,
+    uint16_t v2)
 {
 	if (v1 == v2)
 		return gen_portatom6(cstate, off, v1);
@@ -5977,14 +5886,10 @@ gen_portrangeatom6(compiler_state_t *cstate, u_int off, bpf_u_int32 v1,
 }
 
 static struct block *
-gen_portrangeop6(compiler_state_t *cstate, u_int port1, u_int port2,
-    bpf_u_int32 proto, int dir)
+gen_portrange6(compiler_state_t *cstate, uint16_t port1, uint16_t port2,
+    int proto, int dir)
 {
-	struct block *b0, *b1, *tmp;
-
-	/* ip6 proto 'proto' */
-	/* XXX - catch the first fragment of a fragmented packet? */
-	b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, proto);
+	struct block *b1, *tmp;
 
 	switch (dir) {
 	case Q_SRC:
@@ -6011,41 +5916,8 @@ gen_portrangeop6(compiler_state_t *cstate, u_int port1, u_int port2,
 	default:
 		abort();
 	}
-	gen_and(b0, b1);
 
-	return b1;
-}
-
-static struct block *
-gen_portrange6(compiler_state_t *cstate, u_int port1, u_int port2, int ip_proto,
-    int dir)
-{
-	struct block *b0, *b1, *tmp;
-
-	/* link proto ip6 */
-	b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
-
-	switch (ip_proto) {
-	case IPPROTO_UDP:
-	case IPPROTO_TCP:
-	case IPPROTO_SCTP:
-		b1 = gen_portrangeop6(cstate, port1, port2, (bpf_u_int32)ip_proto,
-		    dir);
-		break;
-
-	case PROTO_UNDEF:
-		tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
-		b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
-		gen_or(tmp, b1);
-		tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
-		gen_or(tmp, b1);
-		break;
-
-	default:
-		abort();
-	}
-	gen_and(b0, b1);
-	return b1;
+	return gen_port6_common(cstate, proto, b1);
 }
 
 static int
@@ -6112,6 +5984,7 @@ gen_protochain(compiler_state_t *cstate, bpf_u_int32 v, int proto)
 	switch (proto) {
 	case Q_IP:
 	case Q_IPV6:
+		assert_maxval(cstate, "protocol number", v, UINT8_MAX);
 		break;
 	case Q_DEFAULT:
 		b0 = gen_protochain(cstate, v, Q_IP);
@@ -6318,12 +6191,10 @@ gen_protochain(compiler_state_t *cstate, bpf_u_int32 v, int proto)
 	 * A = P[X];
 	 * X = X + (P[X + 1] + 2) * 4;
 	 */
-	/* A = X */
-	s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
-	i++;
 	/* A = P[X + packet head]; */
 	s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
 	s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
+	s[i - 1]->s.jt = s[i];
 	i++;
 	/* MEM[reg2] = A */
 	s[i] = new_stmt(cstate, BPF_ST);
@@ -6440,7 +6311,8 @@ gen_proto(compiler_state_t *cstate, bpf_u_int32 v, int proto)
 		 * So we always check for ETHERTYPE_IP.
 		 */
 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
-		b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, v);
+		// 0 <= v <= UINT8_MAX
+		b1 = gen_ip_proto(cstate, (uint8_t)v);
 		gen_and(b0, b1);
 		return b1;
 
@@ -6467,10 +6339,11 @@ gen_proto(compiler_state_t *cstate, bpf_u_int32 v, int proto)
 		 * Also check for a fragment header before the final
 		 * header.
 		 */
-		b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
+		b2 = gen_ip6_proto(cstate, IPPROTO_FRAGMENT);
 		b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, v);
 		gen_and(b2, b1);
-		b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, v);
+		// 0 <= v <= UINT8_MAX
+		b2 = gen_ip6_proto(cstate, (uint8_t)v);
 		gen_or(b2, b1);
 		gen_and(b0, b1);
 		return b1;
@@ -6850,7 +6723,8 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
 	int proto = q.proto;
 	int dir = q.dir;
 	int tproto;
-	u_char *eaddr;
+	u_char *eaddrp;
+	u_char eaddr[6];
 	bpf_u_int32 mask, addr;
 	struct addrinfo *res, *res0;
 	struct sockaddr_in *sin4;
@@ -6887,64 +6761,15 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
 	case Q_DEFAULT:
 	case Q_HOST:
 		if (proto == Q_LINK) {
-			switch (cstate->linktype) {
-
-			case DLT_EN10MB:
-			case DLT_NETANALYZER:
-			case DLT_NETANALYZER_TRANSPARENT:
-				eaddr = pcap_ether_hostton(name);
-				if (eaddr == NULL)
-					bpf_error(cstate,
-					    "unknown ether host '%s'", name);
-				tmp = gen_prevlinkhdr_check(cstate);
-				b = gen_ehostop(cstate, eaddr, dir);
-				if (tmp != NULL)
-					gen_and(tmp, b);
-				free(eaddr);
-				return b;
-
-			case DLT_FDDI:
-				eaddr = pcap_ether_hostton(name);
-				if (eaddr == NULL)
-					bpf_error(cstate,
-					    "unknown FDDI host '%s'", name);
-				b = gen_fhostop(cstate, eaddr, dir);
-				free(eaddr);
-				return b;
-
-			case DLT_IEEE802:
-				eaddr = pcap_ether_hostton(name);
-				if (eaddr == NULL)
-					bpf_error(cstate,
-					    "unknown token ring host '%s'", name);
-				b = gen_thostop(cstate, eaddr, dir);
-				free(eaddr);
-				return b;
-
-			case DLT_IEEE802_11:
-			case DLT_PRISM_HEADER:
-			case DLT_IEEE802_11_RADIO_AVS:
-			case DLT_IEEE802_11_RADIO:
-			case DLT_PPI:
-				eaddr = pcap_ether_hostton(name);
-				if (eaddr == NULL)
-					bpf_error(cstate,
-					    "unknown 802.11 host '%s'", name);
-				b = gen_wlanhostop(cstate, eaddr, dir);
-				free(eaddr);
-				return b;
-
-			case DLT_IP_OVER_FC:
-				eaddr = pcap_ether_hostton(name);
-				if (eaddr == NULL)
-					bpf_error(cstate,
-					    "unknown Fibre Channel host '%s'", name);
-				b = gen_ipfchostop(cstate, eaddr, dir);
-				free(eaddr);
-				return b;
-			}
-
-			bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
+			const char *context = "link host NAME";
+			if (! is_mac48_linktype(cstate->linktype))
+				fail_kw_on_dlt(cstate, context);
+			eaddrp = pcap_ether_hostton(name);
+			if (eaddrp == NULL)
+				bpf_error(cstate, ERRSTR_UNKNOWN_MAC48HOST, name);
+			memcpy(eaddr, eaddrp, sizeof(eaddr));
+			free(eaddrp);
+			return gen_mac48host(cstate, eaddr, q.dir, context);
 		} else if (proto == Q_DECNET) {
 			/*
 			 * A long time ago on Ultrix libpcap supported
@@ -7051,8 +6876,9 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
 			bpf_error(cstate, "illegal port number %d < 0", port);
 		if (port > 65535)
 			bpf_error(cstate, "illegal port number %d > 65535", port);
-		b = gen_port(cstate, port, real_proto, dir);
-		gen_or(gen_port6(cstate, port, real_proto, dir), b);
+		// real_proto can be PROTO_UNDEF
+		b = gen_port(cstate, (uint16_t)port, real_proto, dir);
+		gen_or(gen_port6(cstate, (uint16_t)port, real_proto, dir), b);
 		return b;
 
 	case Q_PORTRANGE:
@@ -7090,15 +6916,22 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
 		if (port2 > 65535)
 			bpf_error(cstate, "illegal port number %d > 65535", port2);
 
-		b = gen_portrange(cstate, port1, port2, real_proto, dir);
-		gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
+		// real_proto can be PROTO_UNDEF
+		b = gen_portrange(cstate, (uint16_t)port1, (uint16_t)port2,
+		    real_proto, dir);
+		gen_or(gen_portrange6(cstate, (uint16_t)port1, (uint16_t)port2,
+		    real_proto, dir), b);
 		return b;
 
 	case Q_GATEWAY:
 #ifndef INET6
-		eaddr = pcap_ether_hostton(name);
-		if (eaddr == NULL)
-			bpf_error(cstate, "unknown ether host: %s", name);
+		if (! is_mac48_linktype(cstate->linktype))
+			fail_kw_on_dlt(cstate, "gateway");
+		eaddrp = pcap_ether_hostton(name);
+		if (eaddrp == NULL)
+			bpf_error(cstate, ERRSTR_UNKNOWN_MAC48HOST, name);
+		memcpy(eaddr, eaddrp, sizeof(eaddr));
+		free(eaddrp);
 
 		res = pcap_nametoaddrinfo(name);
 		cstate->ai = res;
@@ -7107,7 +6940,6 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
 		b = gen_gateway(cstate, eaddr, res, proto);
 		cstate->ai = NULL;
 		freeaddrinfo(res);
-		free(eaddr);
 		if (b == NULL)
 			bpf_error(cstate, "unknown host '%s'", name);
 		return b;
@@ -7276,10 +7108,11 @@ gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
 		if (v > 65535)
 			bpf_error(cstate, "illegal port number %u > 65535", v);
 
+		// proto can be PROTO_UNDEF
 	    {
 		struct block *b;
-		b = gen_port(cstate, v, proto, dir);
-		gen_or(gen_port6(cstate, v, proto, dir), b);
+		b = gen_port(cstate, (uint16_t)v, proto, dir);
+		gen_or(gen_port6(cstate, (uint16_t)v, proto, dir), b);
 		return b;
 	    }
 
@@ -7289,10 +7122,13 @@ gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
 		if (v > 65535)
 			bpf_error(cstate, "illegal port number %u > 65535", v);
 
+		// proto can be PROTO_UNDEF
 	    {
 		struct block *b;
-		b = gen_portrange(cstate, v, v, proto, dir);
-		gen_or(gen_portrange6(cstate, v, v, proto, dir), b);
+		b = gen_portrange(cstate, (uint16_t)v, (uint16_t)v,
+		    proto, dir);
+		gen_or(gen_portrange6(cstate, (uint16_t)v, (uint16_t)v,
+		    proto, dir), b);
 		return b;
 	    }
 
@@ -7386,8 +7222,6 @@ gen_mcode6(compiler_state_t *cstate, const char *s, bpf_u_int32 masklen,
 struct block *
 gen_ecode(compiler_state_t *cstate, const char *s, struct qual q)
 {
-	struct block *b, *tmp;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -7396,40 +7230,13 @@ gen_ecode(compiler_state_t *cstate, const char *s, struct qual q)
 		return (NULL);
 
 	if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
+		const char *context = "link host XX:XX:XX:XX:XX:XX";
+		if (! is_mac48_linktype(cstate->linktype))
+			fail_kw_on_dlt(cstate, context);
 		cstate->e = pcap_ether_aton(s);
 		if (cstate->e == NULL)
 			bpf_error(cstate, "malloc");
-		switch (cstate->linktype) {
-		case DLT_EN10MB:
-		case DLT_NETANALYZER:
-		case DLT_NETANALYZER_TRANSPARENT:
-			tmp = gen_prevlinkhdr_check(cstate);
-			b = gen_ehostop(cstate, cstate->e, (int)q.dir);
-			if (tmp != NULL)
-				gen_and(tmp, b);
-			break;
-		case DLT_FDDI:
-			b = gen_fhostop(cstate, cstate->e, (int)q.dir);
-			break;
-		case DLT_IEEE802:
-			b = gen_thostop(cstate, cstate->e, (int)q.dir);
-			break;
-		case DLT_IEEE802_11:
-		case DLT_PRISM_HEADER:
-		case DLT_IEEE802_11_RADIO_AVS:
-		case DLT_IEEE802_11_RADIO:
-		case DLT_PPI:
-			b = gen_wlanhostop(cstate, cstate->e, (int)q.dir);
-			break;
-		case DLT_IP_OVER_FC:
-			b = gen_ipfchostop(cstate, cstate->e, (int)q.dir);
-			break;
-		default:
-			free(cstate->e);
-			cstate->e = NULL;
-			bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
-			/*NOTREACHED*/
-		}
+		struct block *b = gen_mac48host(cstate, cstate->e, q.dir, context);
 		free(cstate->e);
 		cstate->e = NULL;
 		return (b);
@@ -7704,7 +7511,7 @@ gen_load_internal(compiler_state_t *cstate, int proto, struct arth *inst,
 		/*
 		 * Check if we have an icmp6 next header
 		 */
-		b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58);
+		b = gen_ip6_proto(cstate, 58);
 		if (inst->b)
 			gen_and(inst->b, b);
 		inst->b = b;
@@ -8127,28 +7934,8 @@ gen_broadcast(compiler_state_t *cstate, int proto)
 		case DLT_ARCNET_LINUX:
 			// ARCnet broadcast is [8-bit] destination address 0.
 			return gen_ahostop(cstate, 0, Q_DST);
-		case DLT_EN10MB:
-		case DLT_NETANALYZER:
-		case DLT_NETANALYZER_TRANSPARENT:
-			b1 = gen_prevlinkhdr_check(cstate);
-			b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
-			if (b1 != NULL)
-				gen_and(b1, b0);
-			return b0;
-		case DLT_FDDI:
-			return gen_fhostop(cstate, ebroadcast, Q_DST);
-		case DLT_IEEE802:
-			return gen_thostop(cstate, ebroadcast, Q_DST);
-		case DLT_IEEE802_11:
-		case DLT_PRISM_HEADER:
-		case DLT_IEEE802_11_RADIO_AVS:
-		case DLT_IEEE802_11_RADIO:
-		case DLT_PPI:
-			return gen_wlanhostop(cstate, ebroadcast, Q_DST);
-		case DLT_IP_OVER_FC:
-			return gen_ipfchostop(cstate, ebroadcast, Q_DST);
 		}
-		fail_kw_on_dlt(cstate, "broadcast");
+		return gen_mac48host(cstate, ebroadcast, Q_DST, "broadcast");
 		/*NOTREACHED*/
 
 	case Q_IP:
@@ -8377,8 +8164,6 @@ require_basic_bpf_extensions(compiler_state_t *cstate, const char *keyword)
 struct block *
 gen_ifindex(compiler_state_t *cstate, int ifindex)
 {
-	register struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8392,20 +8177,18 @@ gen_ifindex(compiler_state_t *cstate, int ifindex)
 	switch (cstate->linktype) {
 	case DLT_LINUX_SLL2:
 		/* match packets on this interface */
-		b0 = gen_cmp(cstate, OR_LINKHDR, 4, BPF_W, ifindex);
-		break;
+		return gen_cmp(cstate, OR_LINKHDR, 4, BPF_W, ifindex);
 	default:
 #if defined(__linux__)
 		require_basic_bpf_extensions(cstate, "ifindex");
 		/* match ifindex */
-		b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_IFINDEX, BPF_W,
+		return gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_IFINDEX, BPF_W,
 		             ifindex);
 #else /* defined(__linux__) */
 		fail_kw_on_dlt(cstate, "ifindex");
 		/*NOTREACHED*/
 #endif /* defined(__linux__) */
 	}
-	return (b0);
 }
 
 /*
@@ -8434,14 +8217,12 @@ gen_inbound_outbound(compiler_state_t *cstate, const int outbound)
 	 */
 	switch (cstate->linktype) {
 	case DLT_SLIP:
-		b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B,
+		return gen_cmp(cstate, OR_LINKHDR, 0, BPF_B,
 			  outbound ? SLIPDIR_OUT : SLIPDIR_IN);
-		break;
 
 	case DLT_IPNET:
-		b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H,
+		return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H,
 		    outbound ? IPNET_OUTBOUND : IPNET_INBOUND);
-		break;
 
 	case DLT_LINUX_SLL:
 		/* match outgoing packets */
@@ -8450,7 +8231,7 @@ gen_inbound_outbound(compiler_state_t *cstate, const int outbound)
 			/* to filter on inbound traffic, invert the match */
 			gen_not(b0);
 		}
-		break;
+		return b0;
 
 	case DLT_LINUX_SLL2:
 		/* match outgoing packets */
@@ -8459,16 +8240,14 @@ gen_inbound_outbound(compiler_state_t *cstate, const int outbound)
 			/* to filter on inbound traffic, invert the match */
 			gen_not(b0);
 		}
-		break;
+		return b0;
 
 	case DLT_PFLOG:
-		b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
+		return gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
 		    outbound ? PF_OUT : PF_IN);
-		break;
 
 	case DLT_PPP_PPPD:
-		b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, outbound ? PPP_PPPD_OUT : PPP_PPPD_IN);
-		break;
+		return gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, outbound ? PPP_PPPD_OUT : PPP_PPPD_IN);
 
 	case DLT_JUNIPER_MFR:
 	case DLT_JUNIPER_MLFR:
@@ -8494,8 +8273,7 @@ gen_inbound_outbound(compiler_state_t *cstate, const int outbound)
 	case DLT_JUNIPER_ATM_CEMIC:
 		/* juniper flags (including direction) are stored
 		 * the byte after the 3-byte magic number */
-		b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, outbound ? 0 : 1, 0x01);
-		break;
+		return gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, outbound ? 0 : 1, 0x01);
 
 	default:
 		/*
@@ -8522,19 +8300,18 @@ gen_inbound_outbound(compiler_state_t *cstate, const int outbound)
 			/* to filter on inbound traffic, invert the match */
 			gen_not(b0);
 		}
+		return b0;
 #else /* defined(__linux__) */
 		fail_kw_on_dlt(cstate, outbound ? "outbound" : "inbound");
 		/*NOTREACHED*/
 #endif /* defined(__linux__) */
 	}
-	return (b0);
 }
 
 /* PF firewall log matched interface */
 struct block *
 gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
 {
-	struct block *b0;
 	u_int len, off;
 
 	/*
@@ -8553,17 +8330,14 @@ gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
 		    len-1);
 		/*NOTREACHED*/
 	}
-	b0 = gen_bcmp(cstate, OR_LINKHDR, off, (u_int)strlen(ifname),
+	return gen_bcmp(cstate, OR_LINKHDR, off, (u_int)strlen(ifname),
 	    (const u_char *)ifname);
-	return (b0);
 }
 
 /* PF firewall log ruleset name */
 struct block *
 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8579,17 +8353,14 @@ gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
 		/*NOTREACHED*/
 	}
 
-	b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
+	return gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
 	    (u_int)strlen(ruleset), (const u_char *)ruleset);
-	return (b0);
 }
 
 /* PF firewall log rule number */
 struct block *
 gen_pf_rnr(compiler_state_t *cstate, int rnr)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8599,17 +8370,14 @@ gen_pf_rnr(compiler_state_t *cstate, int rnr)
 
 	assert_pflog(cstate, "rnr");
 
-	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
+	return gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
 		 (bpf_u_int32)rnr);
-	return (b0);
 }
 
 /* PF firewall log sub-rule number */
 struct block *
 gen_pf_srnr(compiler_state_t *cstate, int srnr)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8619,17 +8387,14 @@ gen_pf_srnr(compiler_state_t *cstate, int srnr)
 
 	assert_pflog(cstate, "srnr");
 
-	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
+	return gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
 	    (bpf_u_int32)srnr);
-	return (b0);
 }
 
 /* PF firewall log reason code */
 struct block *
 gen_pf_reason(compiler_state_t *cstate, int reason)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8639,17 +8404,14 @@ gen_pf_reason(compiler_state_t *cstate, int reason)
 
 	assert_pflog(cstate, "reason");
 
-	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
+	return gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
 	    (bpf_u_int32)reason);
-	return (b0);
 }
 
 /* PF firewall log action */
 struct block *
 gen_pf_action(compiler_state_t *cstate, int action)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8659,17 +8421,14 @@ gen_pf_action(compiler_state_t *cstate, int action)
 
 	assert_pflog(cstate, "action");
 
-	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
+	return gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
 	    (bpf_u_int32)action);
-	return (b0);
 }
 
 /* IEEE 802.11 wireless header */
 struct block *
 gen_p80211_type(compiler_state_t *cstate, bpf_u_int32 type, bpf_u_int32 mask)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8684,22 +8443,17 @@ gen_p80211_type(compiler_state_t *cstate, bpf_u_int32 type, bpf_u_int32 mask)
 	case DLT_IEEE802_11_RADIO_AVS:
 	case DLT_IEEE802_11_RADIO:
 	case DLT_PPI:
-		b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, type, mask);
-		break;
+		return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, type, mask);
 
 	default:
 		fail_kw_on_dlt(cstate, "type/subtype");
 		/*NOTREACHED*/
 	}
-
-	return (b0);
 }
 
 struct block *
 gen_p80211_fcdir(compiler_state_t *cstate, bpf_u_int32 fcdir)
 {
-	struct block *b0;
-
 	/*
 	 * Catch errors reported by us and routines below us, and return NULL
 	 * on an error.
@@ -8714,17 +8468,13 @@ gen_p80211_fcdir(compiler_state_t *cstate, bpf_u_int32 fcdir)
 	case DLT_IEEE802_11_RADIO_AVS:
 	case DLT_IEEE802_11_RADIO:
 	case DLT_PPI:
-		break;
+		return gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, fcdir,
+		    IEEE80211_FC1_DIR_MASK);
 
 	default:
 		fail_kw_on_dlt(cstate, "dir");
 		/*NOTREACHED*/
 	}
-
-	b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, fcdir,
-	    IEEE80211_FC1_DIR_MASK);
-
-	return (b0);
 }
 
 // Process an ARCnet host address string.
@@ -9283,7 +9033,7 @@ gen_pppoes(compiler_state_t *cstate, bpf_u_int32 sess_num, int has_sess_num)
  * specified. Parameterized to handle both IPv4 and IPv6. */
 static struct block *
 gen_geneve_check(compiler_state_t *cstate,
-    struct block *(*gen_portfn)(compiler_state_t *, u_int, int, int),
+    struct block *(*gen_portfn)(compiler_state_t *, uint16_t, int, int),
     enum e_offrel offrel, bpf_u_int32 vni, int has_vni)
 {
 	struct block *b0, *b1;
@@ -9552,7 +9302,7 @@ gen_geneve(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
  * specified. Parameterized to handle both IPv4 and IPv6. */
 static struct block *
 gen_vxlan_check(compiler_state_t *cstate,
-    struct block *(*gen_portfn)(compiler_state_t *, u_int, int, int),
+    struct block *(*gen_portfn)(compiler_state_t *, uint16_t, int, int),
     enum e_offrel offrel, bpf_u_int32 vni, int has_vni)
 {
 	struct block *b0, *b1;
@@ -9776,68 +9526,41 @@ static struct block *
 gen_atmfield_code_internal(compiler_state_t *cstate, int atmfield,
     bpf_u_int32 jvalue, int jtype, int reverse)
 {
-	struct block *b0;
-
-	/*
-	 * This check is a no-op for A_MSGTYPE so long as the only incoming
-	 * code path is from gen_atmmulti_abbrev(), which makes the same
-	 * check first; also for A_PROTOTYPE so long as the only incoming code
-	 * paths are from gen_atmtype_abbrev(), which makes the same check
-	 * first, or from gen_llc_internal() or gen_linktype(), which restrict
-	 * it to DLT_SUNATM.
-	 */
 	assert_atm(cstate, atmkw(atmfield));
 
 	switch (atmfield) {
 
 	case A_VPI:
 		assert_maxval(cstate, "VPI", jvalue, UINT8_MAX);
-		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B,
+		return gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B,
 		    0xffffffffU, jtype, reverse, jvalue);
-		break;
 
 	case A_VCI:
 		assert_maxval(cstate, "VCI", jvalue, UINT16_MAX);
-		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H,
+		return gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H,
 		    0xffffffffU, jtype, reverse, jvalue);
-		break;
-
-	case A_PROTOTYPE:
-		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B,
-		    0x0fU, jtype, reverse, jvalue);
-		break;
-
-	case A_MSGTYPE:
-		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
-		    0xffffffffU, jtype, reverse, jvalue);
-		break;
 
 	default:
 		abort();
 	}
-	return b0;
 }
 
 static struct block *
-gen_atmtype_metac(compiler_state_t *cstate)
+gen_atm_vpi(compiler_state_t *cstate, const uint8_t v)
 {
-	struct block *b0, *b1;
-
-	b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-	b1 = gen_atmfield_code_internal(cstate, A_VCI, 1, BPF_JEQ, 0);
-	gen_and(b0, b1);
-	return b1;
+	return gen_atmfield_code_internal(cstate, A_VPI, v, BPF_JEQ, 0);
 }
 
 static struct block *
-gen_atmtype_sc(compiler_state_t *cstate)
+gen_atm_vci(compiler_state_t *cstate, const uint16_t v)
 {
-	struct block *b0, *b1;
+	return gen_atmfield_code_internal(cstate, A_VCI, v, BPF_JEQ, 0);
+}
 
-	b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-	b1 = gen_atmfield_code_internal(cstate, A_VCI, 5, BPF_JEQ, 0);
-	gen_and(b0, b1);
-	return b1;
+static struct block *
+gen_atm_prototype(compiler_state_t *cstate, const uint8_t v)
+{
+	return gen_mcmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, v, 0x0fU);
 }
 
 static struct block *
@@ -9845,7 +9568,7 @@ gen_atmtype_llc(compiler_state_t *cstate)
 {
 	struct block *b0;
 
-	b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
+	b0 = gen_atm_prototype(cstate, PT_LLC);
 	cstate->linktype = cstate->prevlinktype;
 	return b0;
 }
@@ -9883,45 +9606,49 @@ gen_atmtype_abbrev(compiler_state_t *cstate, int type)
 
 	case A_METAC:
 		/* Get all packets in Meta signalling Circuit */
-		b1 = gen_atmtype_metac(cstate);
-		break;
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 1);
+		gen_and(b0, b1);
+		return b1;
 
 	case A_BCC:
 		/* Get all packets in Broadcast Circuit*/
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 2, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 2);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_OAMF4SC:
 		/* Get all cells in Segment OAM F4 circuit*/
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 3);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_OAMF4EC:
 		/* Get all cells in End-to-End OAM F4 Circuit*/
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 4);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_SC:
 		/*  Get all packets in connection Signalling Circuit */
-		b1 = gen_atmtype_sc(cstate);
-		break;
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 5);
+		gen_and(b0, b1);
+		return b1;
 
 	case A_ILMIC:
 		/* Get all packets in ILMI Circuit */
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 16, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
+		b1 = gen_atm_vci(cstate, 16);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_LANE:
 		/* Get all LANE packets */
-		b1 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
+		b1 = gen_atm_prototype(cstate, PT_LANE);
 
 		/*
 		 * Arrange that all subsequent tests assume LANE
@@ -9938,12 +9665,11 @@ gen_atmtype_abbrev(compiler_state_t *cstate, int type)
 		cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14;	/* Ethernet */
 		cstate->off_nl = 0;			/* Ethernet II */
 		cstate->off_nl_nosnap = 3;		/* 802.3+802.2 */
-		break;
+		return b1;
 
 	default:
 		abort();
 	}
-	return b1;
 }
 
 /*
@@ -9970,9 +9696,8 @@ gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
 	switch (type) {
 
 	case M_FISU:
-		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
+		return gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
 		    0x3fU, BPF_JEQ, 0, 0U);
-		break;
 
 	case M_LSSU:
 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
@@ -9980,17 +9705,15 @@ gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
 		b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
 		    0x3fU, BPF_JGT, 0, 0U);
 		gen_and(b1, b0);
-		break;
+		return b0;
 
 	case M_MSU:
-		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
+		return gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B,
 		    0x3fU, BPF_JGT, 0, 2U);
-		break;
 
 	case MH_FISU:
-		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
+		return gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
 		    0xff80U, BPF_JEQ, 0, 0U);
-		break;
 
 	case MH_LSSU:
 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
@@ -9998,17 +9721,15 @@ gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
 		b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
 		    0xff80U, BPF_JGT, 0, 0U);
 		gen_and(b1, b0);
-		break;
+		return b0;
 
 	case MH_MSU:
-		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
+		return gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H,
 		    0xff80U, BPF_JGT, 0, 0x0100U);
-		break;
 
 	default:
 		abort();
 	}
-	return b0;
 }
 
 /*
@@ -10023,7 +9744,6 @@ static struct block *
 gen_mtp3field_code_internal(compiler_state_t *cstate, int mtp3field,
     bpf_u_int32 jvalue, int jtype, int reverse)
 {
-	struct block *b0;
 	u_int newoff_sio;
 	u_int newoff_opc;
 	u_int newoff_dpc;
@@ -10052,9 +9772,8 @@ gen_mtp3field_code_internal(compiler_state_t *cstate, int mtp3field,
 	case M_SIO:
 		assert_maxval(cstate, ss7kw(mtp3field), jvalue, MTP2_SIO_MAXVAL);
 		// Here the bitmask means "do not apply a bitmask".
-		b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, UINT32_MAX,
+		return gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, UINT32_MAX,
 		    jtype, reverse, jvalue);
-		break;
 
 	/*
 	 * See UTU-T Rec. Q.704, Section 2.2, Figure 3/Q.704.
@@ -10091,10 +9810,9 @@ gen_mtp3field_code_internal(compiler_state_t *cstate, int mtp3field,
 		/* FALLTHROUGH */
 	case M_OPC:
 		assert_maxval(cstate, ss7kw(mtp3field), jvalue, MTP3_PC_MAXVAL);
-		b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W,
+		return gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W,
 		    SWAPLONG(MTP3_PC_MAXVAL << 14), jtype, reverse,
 		    SWAPLONG(jvalue << 14));
-		break;
 
 	case MH_DPC:
 		newoff_dpc += 3;
@@ -10102,10 +9820,9 @@ gen_mtp3field_code_internal(compiler_state_t *cstate, int mtp3field,
 
 	case M_DPC:
 		assert_maxval(cstate, ss7kw(mtp3field), jvalue, MTP3_PC_MAXVAL);
-		b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_H,
+		return gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_H,
 		    SWAPSHORT(MTP3_PC_MAXVAL), jtype, reverse,
 		    SWAPSHORT(jvalue));
-		break;
 
 	case MH_SLS:
 		newoff_sls += 3;
@@ -10113,15 +9830,13 @@ gen_mtp3field_code_internal(compiler_state_t *cstate, int mtp3field,
 
 	case M_SLS:
 		assert_maxval(cstate, ss7kw(mtp3field), jvalue, MTP3_SLS_MAXVAL);
-		b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B,
+		return gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B,
 		    MTP3_SLS_MAXVAL << 4, jtype, reverse,
 		    jvalue << 4);
-		break;
 
 	default:
 		abort();
 	}
-	return b0;
 }
 
 struct block *
@@ -10140,44 +9855,14 @@ gen_mtp3field_code(compiler_state_t *cstate, int mtp3field,
 }
 
 static struct block *
-gen_msg_abbrev(compiler_state_t *cstate, int type)
+gen_msg_abbrev(compiler_state_t *cstate, const uint8_t type)
 {
-	struct block *b1;
-
 	/*
 	 * Q.2931 signalling protocol messages for handling virtual circuits
 	 * establishment and teardown
 	 */
-	switch (type) {
-
-	case A_SETUP:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
-		break;
-
-	case A_CALLPROCEED:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
-		break;
-
-	case A_CONNECT:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
-		break;
-
-	case A_CONNECTACK:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
-		break;
-
-	case A_RELEASE:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
-		break;
-
-	case A_RELEASE_DONE:
-		b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
-		break;
-
-	default:
-		abort();
-	}
-	return b1;
+	return gen_cmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS,
+	    BPF_B, type);
 }
 
 struct block *
@@ -10198,58 +9883,57 @@ gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
 
 	case A_OAM:
 		/* OAM F4 type */
-		b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
+		b0 = gen_atm_vci(cstate, 3);
+		b1 = gen_atm_vci(cstate, 4);
 		gen_or(b0, b1);
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_OAMF4:
 		/* OAM F4 type */
-		b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
-		b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
+		b0 = gen_atm_vci(cstate, 3);
+		b1 = gen_atm_vci(cstate, 4);
 		gen_or(b0, b1);
-		b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
+		b0 = gen_atm_vpi(cstate, 0);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_CONNECTMSG:
 		/*
 		 * Get Q.2931 signalling messages for switched
 		 * virtual connection
 		 */
-		b0 = gen_msg_abbrev(cstate, A_SETUP);
-		b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
+		b0 = gen_msg_abbrev(cstate, SETUP);
+		b1 = gen_msg_abbrev(cstate, CALL_PROCEED);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_CONNECT);
+		b0 = gen_msg_abbrev(cstate, CONNECT);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
+		b0 = gen_msg_abbrev(cstate, CONNECT_ACK);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_RELEASE);
+		b0 = gen_msg_abbrev(cstate, RELEASE);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
+		b0 = gen_msg_abbrev(cstate, RELEASE_DONE);
 		gen_or(b0, b1);
-		b0 = gen_atmtype_sc(cstate);
+		b0 = gen_atmtype_abbrev(cstate, A_SC);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	case A_METACONNECT:
-		b0 = gen_msg_abbrev(cstate, A_SETUP);
-		b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
+		b0 = gen_msg_abbrev(cstate, SETUP);
+		b1 = gen_msg_abbrev(cstate, CALL_PROCEED);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_CONNECT);
+		b0 = gen_msg_abbrev(cstate, CONNECT);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_RELEASE);
+		b0 = gen_msg_abbrev(cstate, RELEASE);
 		gen_or(b0, b1);
-		b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
+		b0 = gen_msg_abbrev(cstate, RELEASE_DONE);
 		gen_or(b0, b1);
-		b0 = gen_atmtype_metac(cstate);
+		b0 = gen_atmtype_abbrev(cstate, A_METAC);
 		gen_and(b0, b1);
-		break;
+		return b1;
 
 	default:
 		abort();
 	}
-	return b1;
 }