Merge pull request #84 from Igalia/low-icmp6

Implement 'icmp6'

doc/Makefile

@@ -30,7 +30,8 @@ EXAMPLES = \
 	ip-proto-sctp.md \
 	decnet-src-10.15.md \
 	decnet-host-10.15.md \
-	l1.md
+	l1.md \
+	icmp6.md
 
 PFLUA = \
 	../src/pf.lua \
@@ -135,3 +136,6 @@ decnet-host-10.15.md:
 
 l1.md:
 	../tools/dump-markdown "l1" > $@.tmp && mv $@.tmp $@
+
+icmp6.md:
+	../tools/dump-markdown "icmp6" > $@.tmp && mv $@.tmp $@

doc/icmp6.md

@@ -0,0 +1,68 @@
+# icmp6
+
+
+## BPF
+
+```
+000: A = P[12:2]
+001: if (A == 34525) goto 2 else goto 8
+002: A = P[20:1]
+003: if (A == 58) goto 7 else goto 4
+004: if (A == 44) goto 5 else goto 8
+005: A = P[54:1]
+006: if (A == 58) goto 7 else goto 8
+007: return 65535
+008: return 0
+```
+
+
+## BPF cross-compiled to Lua
+
+```
+return function (P, length)
+   local A = 0
+   if 14 > length then return 0 end
+   A = bit.bor(bit.lshift(P[12], 8), P[12+1])
+   if not (A==34525) then goto L7 end
+   if 21 > length then return 0 end
+   A = P[20]
+   if (A==58) then goto L6 end
+   if not (A==44) then goto L7 end
+   if 55 > length then return 0 end
+   A = P[54]
+   if not (A==58) then goto L7 end
+   ::L6::
+   do return 65535 end
+   ::L7::
+   do return 0 end
+   error("end of bpf")
+end
+```
+
+
+## Direct pflang compilation
+
+```
+return function(P,length)
+   if not (length >= 54) then do return false end end
+   do
+      local v1 = ffi.cast("uint16_t*", P+12)[0]
+      if not (v1 == 56710) then do return false end end
+      do
+         local v2 = P[20]
+         if v2 == 58 then do return true end end
+         do
+            if not (length >= 55) then do return false end end
+            do
+               if not (v2 == 44) then do return false end end
+               do
+                  local v3 = P[54]
+                  do return v3 == 58 end
+               end
+            end
+         end
+      end
+   end
+end
+```
+

src/pf/expand.lua

@@ -70,6 +70,7 @@ local ether_min_payloads = {
 
 -- IP protocols
 local PROTO_ICMP = 1          -- 0x1
+local PROTO_ICMP6 = 58        -- 0x3a
 local PROTO_TCP = 6           -- 0x6
 local PROTO_UDP = 17          -- 0x11
 local PROTO_SCTP = 132        -- 0x84
@@ -405,16 +406,17 @@ local function expand_ip_protochain(expr)
 end
 
 local ip_protos = {
-   icmp = PROTO_ICMP,
-   igmp = PROTO_IGMP,
-   igrp = PROTO_IGRP,
-   pim  = PROTO_PIM,
-   ah   = PROTO_AH,
-   esp  = PROTO_ESP,
-   vrrp = PROTO_VRRP,
-   udp  = PROTO_UDP,
-   tcp  = PROTO_TCP,
-   sctp = PROTO_SCTP,
+   icmp  = PROTO_ICMP,
+   icmp6 = PROTO_ICMP6,
+   igmp  = PROTO_IGMP,
+   igrp  = PROTO_IGRP,
+   pim   = PROTO_PIM,
+   ah    = PROTO_AH,
+   esp   = PROTO_ESP,
+   vrrp  = PROTO_VRRP,
+   udp   = PROTO_UDP,
+   tcp   = PROTO_TCP,
+   sctp  = PROTO_SCTP,
 }
 
 local function expand_ip4_proto(expr)
@@ -859,6 +861,7 @@ local primitive_expanders = {
    udp_src_portrange = expand_udp_src_portrange,
    udp_dst_portrange = expand_udp_dst_portrange,
    icmp = function(expr) return has_ip_protocol(PROTO_ICMP) end,
+   icmp6 = function(expr) return has_ipv6_protocol(PROTO_ICMP6) end,
    igmp = function(expr) return has_ip_protocol(PROTO_IGMP) end,
    igrp = function(expr) return has_ip_protocol(PROTO_IGRP) end,
    pim = function(expr) return has_ip_protocol(PROTO_PIM) end,

src/pf/parse.lua

@@ -705,6 +705,7 @@ local primitives = {
    tcp = table_parser(tcp_or_udp_types, nullary()),
    udp = table_parser(tcp_or_udp_types, nullary()),
    icmp = nullary(),
+   icmp6 = nullary(),
    igmp = nullary(),
    igrp = nullary(),
    pim = nullary(),