ovn: Exclude inport and outport symbol tables from conjunction

If there are multiple ACLs associated with a port group and they
match on a range of some field, then ovn-controller doesn't install
the flows properly and this results in broken ACL functionality.

For example, if there is a port group - pg1 with logical ports - [p1, p2]
and if there are below ACLs (only match condition is shown)

1 -  outport == @pg1 && ip4 && tcp.dst >= 500 && tcp.dst <= 501
2 -  outport == @pg1 && ip4 && tcp.dst >= 600 && tcp.dst <= 601

The first ACL will result in the below OF flows

1.  conj_id=1,tcp
2.  tcp,reg15=0x11: conjunction(1, 1/2)
3.  tcp,reg15=0x12: conjunction(1, 1/2)
5.  tcp,tp_dst=500: conjunction(1, 2/2)
6.  tcp,tp_dst=501: conjunction(1, 2/2)

The second ACL will result in the below OF flows
7.  conj_id=2,tcp
8.  tcp,reg15=0x11: conjunction(2, 1/2)
9.  tcp,reg15=0x12: conjunction(2, 1/2)
11. tcp,tp_dst=600: conjunction(2, 2/2)
12. tcp,tp_dst=601: conjunction(2, 3/2)

The OF flows (2) and (8) have the exact match but with different action.
This results in only one of the flows getting installed. The same goes
for the flows (3) and (9). And this completely breaks the ACL functionality
for such scenarios.

In order to fix this issue, this patch excludes the 'inport' and 'outport' symbols
from conjunction. With this patch we will have the below flows.

tcp,reg15=0x11,tp_dst=500
tcp,reg15=0x11,tp_dst=501
tcp,reg15=0x12,tp_dst=500
tcp,reg15=0x12,tp_dst=501
tcp,reg15=0x13,tp_dst=500
tcp,reg15=0x13,tp_dst=501
tcp,reg15=0x11,tp_dst=600
tcp,reg15=0x11,tp_dst=601
tcp,reg15=0x12,tp_dst=600
tcp,reg15=0x12,tp_dst=601
tcp,reg15=0x13,tp_dst=600
tcp,reg15=0x13,tp_dst=601

Acked-by: Mark Michelson <mmichels@redhat.com>
Acked-by: Daniel Alvarez <dalvarez@redhat.com>
Signed-off-by: Numan Siddique <nusiddiq@redhat.com>

(cherry-picked from ovn commit 298701d)

Signed-off-by: Ben Pfaff <blp@ovn.org>

ovn/lib/expr.c

@@ -1499,7 +1499,7 @@ expr_symtab_add_string(struct shash *symtab, const char *name,
     const struct mf_field *field = mf_from_id(id);
     struct expr_symbol *symbol;
 
-    symbol = add_symbol(symtab, name, 0, prereqs, EXPR_L_NOMINAL, false,
+    symbol = add_symbol(symtab, name, 0, prereqs, EXPR_L_NOMINAL, true,
                         field->writable);
     symbol->field = field;
     return symbol;

tests/ovn.at

@@ -573,6 +573,24 @@ ip,reg14=0x6
 ipv6,reg14=0x5
 ipv6,reg14=0x6
 ])
+AT_CHECK([expr_to_flow 'inport == {"eth0", "eth1", "eth2"} && ip4 && tcp && tcp.dst == {500, 501}'], [0], [dnl
+tcp,reg14=0x5,tp_dst=500
+tcp,reg14=0x5,tp_dst=501
+tcp,reg14=0x6,tp_dst=500
+tcp,reg14=0x6,tp_dst=501
+])
+AT_CHECK([expr_to_flow 'outport == {"eth0", "eth1", "eth2"} && ip4 && tcp && tcp.src == {400, 401} && tcp.dst == {500, 501}'], [0], [dnl
+conj_id=1,tcp,reg15=0x5
+conj_id=2,tcp,reg15=0x6
+tcp,reg15=0x5,tp_dst=500: conjunction(1, 0/2)
+tcp,reg15=0x5,tp_dst=501: conjunction(1, 0/2)
+tcp,reg15=0x5,tp_src=400: conjunction(1, 1/2)
+tcp,reg15=0x5,tp_src=401: conjunction(1, 1/2)
+tcp,reg15=0x6,tp_dst=500: conjunction(2, 0/2)
+tcp,reg15=0x6,tp_dst=501: conjunction(2, 0/2)
+tcp,reg15=0x6,tp_src=400: conjunction(2, 1/2)
+tcp,reg15=0x6,tp_src=401: conjunction(2, 1/2)
+])
 AT_CHECK([expr_to_flow 'inport == "eth0" && inport == "eth1"'], [0], [dnl
 (no flows)
 ])
@@ -677,6 +695,14 @@ reg15=0x11
 reg15=0x12
 reg15=0x13
 ])
+AT_CHECK([expr_to_flow 'outport == @pg1 && ip4.src == {10.0.0.4, 10.0.0.5}'], [0], [dnl
+ip,reg15=0x11,nw_src=10.0.0.4
+ip,reg15=0x11,nw_src=10.0.0.5
+ip,reg15=0x12,nw_src=10.0.0.4
+ip,reg15=0x12,nw_src=10.0.0.5
+ip,reg15=0x13,nw_src=10.0.0.4
+ip,reg15=0x13,nw_src=10.0.0.5
+])
 AT_CHECK([expr_to_flow 'outport == {@pg_empty}'], [0], [dnl
 (no flows)
 ])