The packet in userdata generated by ovn-controller when translating the
put_dhcpv6_opt action includes 16-bit integers.

Currently these 16-bit integers are encoded with native endianness.
This is ok becase the only consumer of that userdata is ovn-controller
itself, but it means that the OpenFlow action we're generating might
not really be the same on different hosts.

I think it's better to encode the userdata as big-endian, like the rest
of OpenFlow messages.

This fixes a test failure on big-endian platforms, because the generated
OpenFlow bytes were different than expected (the expectation was
generated on a little endian machine).

Now 'struct dhcp_opt6_header' is identical to 'struct
dhcpv6_opt_header', but I chose to keep them separate, because they
have different purposes.  I also renamed the members to avoid confusion.

I haven't tested this on a real setup.

CC: Numan Siddique <[email protected]>
Reported-at: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=840770
Signed-off-by: Daniele Di Proietto <[email protected]>
---
 ovn/controller/pinctrl.c | 28 +++++++++++++---------------
 ovn/lib/actions.c        | 19 ++++++++++++-------
 ovn/lib/ovn-dhcp.h       |  5 +++--
 tests/ovn.at             |  8 ++++----
 4 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/ovn/controller/pinctrl.c b/ovn/controller/pinctrl.c
index db9e441..849fbce 100644
--- a/ovn/controller/pinctrl.c
+++ b/ovn/controller/pinctrl.c
@@ -385,13 +385,13 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
             return false;
         }
 
-        uint8_t *userdata_opt_data = ofpbuf_try_pull(userdata,
-                                                     userdata_opt->len);
+        size_t size = ntohs(userdata_opt->size);
+        uint8_t *userdata_opt_data = ofpbuf_try_pull(userdata, size);
         if (!userdata_opt_data) {
             return false;
         }
 
-        switch (userdata_opt->code) {
+        switch (ntohs(userdata_opt->opt_code)) {
         case DHCPV6_OPT_SERVER_ID_CODE:
         {
             /* The Server Identifier option carries a DUID
@@ -405,7 +405,7 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
                 out_dhcpv6_opts, sizeof *opt_server_id);
 
             opt_server_id->opt.code = htons(DHCPV6_OPT_SERVER_ID_CODE);
-            opt_server_id->opt.len = htons(userdata_opt->len + 4);
+            opt_server_id->opt.len = htons(size + 4);
             opt_server_id->duid_type = htons(DHCPV6_DUID_LL);
             opt_server_id->hw_type = htons(DHCPV6_HW_TYPE_ETH);
             memcpy(&opt_server_id->mac, userdata_opt_data,
@@ -415,7 +415,7 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
 
         case DHCPV6_OPT_IA_ADDR_CODE:
         {
-            if (userdata_opt->len != sizeof(struct in6_addr)) {
+            if (size != sizeof(struct in6_addr)) {
                 return false;
             }
 
@@ -444,9 +444,8 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
             struct dhcpv6_opt_ia_addr *opt_ia_addr = ofpbuf_put_zeros(
                 out_dhcpv6_opts, sizeof *opt_ia_addr);
             opt_ia_addr->opt.code = htons(DHCPV6_OPT_IA_ADDR_CODE);
-            opt_ia_addr->opt.len = htons(userdata_opt->len + 8);
-            memcpy(opt_ia_addr->ipv6.s6_addr, userdata_opt_data,
-                   userdata_opt->len);
+            opt_ia_addr->opt.len = htons(size + 8);
+            memcpy(opt_ia_addr->ipv6.s6_addr, userdata_opt_data, size);
             opt_ia_addr->t1 = OVS_BE32_MAX;
             opt_ia_addr->t2 = OVS_BE32_MAX;
             break;
@@ -457,8 +456,8 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
             struct dhcpv6_opt_header *opt_dns = ofpbuf_put_zeros(
                 out_dhcpv6_opts, sizeof *opt_dns);
             opt_dns->code = htons(DHCPV6_OPT_DNS_SERVER_CODE);
-            opt_dns->len = htons(userdata_opt->len);
-            ofpbuf_put(out_dhcpv6_opts, userdata_opt_data, userdata_opt->len);
+            opt_dns->len = htons(size);
+            ofpbuf_put(out_dhcpv6_opts, userdata_opt_data, size);
             break;
         }
 
@@ -467,11 +466,10 @@ compose_out_dhcpv6_opts(struct ofpbuf *userdata,
             struct dhcpv6_opt_header *opt_dsl = ofpbuf_put_zeros(
                 out_dhcpv6_opts, sizeof *opt_dsl);
             opt_dsl->code = htons(DHCPV6_OPT_DOMAIN_SEARCH_CODE);
-            opt_dsl->len = htons(userdata_opt->len + 2);
-            uint8_t *data = ofpbuf_put_zeros(out_dhcpv6_opts,
-                                              userdata_opt->len + 2);
-            *data = userdata_opt->len;
-            memcpy(data + 1, userdata_opt_data, userdata_opt->len);
+            opt_dsl->len = htons(size + 2);
+            uint8_t *data = ofpbuf_put_zeros(out_dhcpv6_opts, size + 2);
+            *data = size;
+            memcpy(data + 1, userdata_opt_data, size);
             break;
         }
 
diff --git a/ovn/lib/actions.c b/ovn/lib/actions.c
index df526c0..fa8f175 100644
--- a/ovn/lib/actions.c
+++ b/ovn/lib/actions.c
@@ -1527,21 +1527,26 @@ encode_put_dhcpv6_option(const struct 
ovnact_dhcp_option *o,
                          struct ofpbuf *ofpacts)
 {
     struct dhcp_opt6_header *opt = ofpbuf_put_uninit(ofpacts, sizeof *opt);
-    opt->code = o->option->code;
-
     const union expr_constant *c = o->value.values;
     size_t n_values = o->value.n_values;
+    size_t size;
+
+    opt->opt_code = htons(o->option->code);
+
     if (!strcmp(o->option->type, "ipv6")) {
-        opt->len = n_values * sizeof(struct in6_addr);
+        size = n_values * sizeof(struct in6_addr);
+        opt->size = htons(size);
         for (size_t i = 0; i < n_values; i++) {
             ofpbuf_put(ofpacts, &c[i].value.ipv6, sizeof(struct in6_addr));
         }
     } else if (!strcmp(o->option->type, "mac")) {
-        opt->len = sizeof(struct eth_addr);
-        ofpbuf_put(ofpacts, &c->value.mac, opt->len);
+        size = sizeof(struct eth_addr);
+        opt->size = htons(size);
+        ofpbuf_put(ofpacts, &c->value.mac, size);
     } else if (!strcmp(o->option->type, "str")) {
-        opt->len = strlen(c->string);
-        ofpbuf_put(ofpacts, c->string, opt->len);
+        size = strlen(c->string);
+        opt->size = htons(size);
+        ofpbuf_put(ofpacts, c->string, size);
     }
 }
 
diff --git a/ovn/lib/ovn-dhcp.h b/ovn/lib/ovn-dhcp.h
index ecfcc03..d5561ed 100644
--- a/ovn/lib/ovn-dhcp.h
+++ b/ovn/lib/ovn-dhcp.h
@@ -109,9 +109,10 @@ dhcp_opts_destroy(struct hmap *dhcp_opts)
     hmap_destroy(dhcp_opts);
 }
 
+/* Used in the OpenFlow PACKET_IN userdata */
 struct dhcp_opt6_header {
-    uint16_t code;
-    uint16_t len;
+    ovs_be16 opt_code;
+    ovs_be16 size;
 };
 
 /* Supported DHCPv6 Message Types */
diff --git a/tests/ovn.at b/tests/ovn.at
index 38fd1e5..cb21210 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -950,17 +950,17 @@ put_nd(inport, nd.target, nd.sll);
 
 # put_dhcpv6_opts
 reg1[0] = put_dhcpv6_opts(ia_addr = ae70::4, server_id = 00:00:00:00:10:02);
-    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.05.00.10.00.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.04.02.00.06.00.00.00.00.00.10.02,pause)
+    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.00.05.00.10.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.04.00.02.00.06.00.00.00.00.10.02,pause)
 reg1[0] = put_dhcpv6_opts();
     encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40,pause)
 reg1[0] = put_dhcpv6_opts(dns_server={ae70::1,ae70::2});
     formats as reg1[0] = put_dhcpv6_opts(dns_server = {ae70::1, ae70::2});
-    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.17.00.20.00.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.01.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.02,pause)
+    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.00.17.00.20.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.01.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.02,pause)
 reg1[0] = put_dhcpv6_opts(server_id=12:34:56:78:9a:bc, 
dns_server={ae70::1,ae89::2});
     formats as reg1[0] = put_dhcpv6_opts(server_id = 12:34:56:78:9a:bc, 
dns_server = {ae70::1, ae89::2});
-    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.02.00.06.00.12.34.56.78.9a.bc.17.00.20.00.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.01.ae.89.00.00.00.00.00.00.00.00.00.00.00.00.00.02,pause)
+    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.00.02.00.06.12.34.56.78.9a.bc.00.17.00.20.ae.70.00.00.00.00.00.00.00.00.00.00.00.00.00.01.ae.89.00.00.00.00.00.00.00.00.00.00.00.00.00.02,pause)
 reg1[0] = put_dhcpv6_opts(domain_search = "ovn.org");
-    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.18.00.07.00.6f.76.6e.2e.6f.72.67,pause)
+    encodes as 
controller(userdata=00.00.00.05.00.00.00.00.00.01.de.10.00.00.00.40.00.18.00.07.6f.76.6e.2e.6f.72.67,pause)
 reg1[0] = put_dhcpv6_opts(x = 1.2.3.4);
     Syntax error at `x' expecting DHCPv6 option name.
 reg1[0] = put_dhcpv6_opts(ia_addr=ae70::4, "hi");
-- 
2.10.2

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