[ovs-dev] [PATCH v3 2/2 ovn] Add support for DHCP domain search option (119)
Ankur Sharma
svc.mail.git at nutanix.com
Mon Jun 1 17:08:46 UTC 2020
From: Dhathri Purohith <dhathri.purohith at nutanix.com>
Domain search list is encoded according to the specifications in RFC 1035,
section 4.1.4.
Signed-off-by: Dhathri Purohith <dhathri.purohith at nutanix.com>
---
lib/actions.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++-
lib/ovn-l7.h | 3 ++
northd/ovn-northd.c | 1 +
ovn-sb.ovsschema | 6 ++--
ovn-sb.xml | 11 ++++++
tests/ovn.at | 3 ++
tests/test-ovn.c | 1 +
7 files changed, 121 insertions(+), 4 deletions(-)
diff --git a/lib/actions.c b/lib/actions.c
index f21be6d..8f5ed61 100644
--- a/lib/actions.c
+++ b/lib/actions.c
@@ -1982,7 +1982,8 @@ parse_gen_opt(struct action_context *ctx, struct ovnact_gen_option *o,
return;
}
- if (!strcmp(o->option->type, "str")) {
+ if (!strcmp(o->option->type, "str") ||
+ !strcmp(o->option->type, "domains")) {
if (o->value.type != EXPR_C_STRING) {
lexer_error(ctx->lexer, "%s option %s requires string value.",
opts_type, o->option->name);
@@ -2317,6 +2318,103 @@ encode_put_dhcpv4_option(const struct ovnact_gen_option *o,
opt_header[1] = sizeof(ovs_be32);
ofpbuf_put(ofpacts, &c->value.ipv4, sizeof(ovs_be32));
}
+ } else if (!strcmp(o->option->type, "domains")) {
+ /* Please refer to RFC 1035, section 4.1.4 for the format of encoding
+ * domain names. Below is an example for encoding a search list
+ * consisting of the "abc.com" and "xyz.abc.com".
+ *
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ * |119|14 | 3 |'a'|'b'|'c'| 3 |'c'|'o'|'m'| 0 |'x'|'y'|'z'|xC0|x00|
+ * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
+ *
+ * The encoding of "abc.com" ends with 0 to mark the end of the
+ * domain name as required by RFC 1035.
+ *
+ * The encoding of "xyz" (for "xyz.abc.com") ends with the two-octet
+ * compression pointer C000 (hex), which points to offset 0 where
+ * another validly encoded domain name can be found to complete
+ * the name ("abc.com").
+ */
+ typedef struct namemap_node {
+ struct hmap_node node;
+ uint16_t offset;
+ char *name;
+ } namemap_node;
+ struct hmap namemap;
+ hmap_init(&namemap);
+ namemap_node *ref;
+ /* Encoding adds 2 bytes (one for length and one for delimiter) for
+ * every domain name that is unique. If all the domain names are unique
+ * (which probably never happens in real world), then encoded string
+ * could be longer than the original string. Just to be on the safer
+ * side, allocate the (approx.) worst case length here.
+ */
+ uint8_t *dns_encoded = xzalloc(2 * strlen(c->string));
+ uint8_t encode_offset = 0;
+ char *domain_list = xstrdup(c->string), *dom_ptr = NULL;
+ for (char *domain = strtok_r(domain_list, ",", &dom_ptr);
+ domain != NULL;
+ domain = strtok_r(NULL, ",", &dom_ptr)) {
+ if (strlen(domain) > DOMAIN_NAME_MAX_LEN) {
+ VLOG_WARN("Domain names longer than 255 characters are not"
+ "supported");
+ goto out;
+ }
+ char *label_ptr = NULL, *label;
+ for (label = strtok_r(domain, ".", &label_ptr);
+ label != NULL;
+ label = strtok_r(NULL, ".", &label_ptr)) {
+ ref = NULL;
+ /* Check if we have already encoded this label and
+ * fill in the reference, if yes. */
+ uint32_t label_hash = hash_string(label, 0);
+ HMAP_FOR_EACH_IN_BUCKET (ref, node, label_hash, &namemap) {
+ if (!strcmp(label, ref->name)) {
+ ovs_be16 temp = htons(0xc000) | htons(ref->offset);
+ memcpy(dns_encoded + encode_offset, &temp,
+ sizeof(temp));
+ encode_offset += sizeof(temp);
+ break;
+ }
+ }
+ /* Break, since we have already filled the offset for this
+ * domain. */
+ if (ref != NULL) {
+ break;
+ } else {
+ /* The label was not encoded before, encode it now and add
+ * the offset to the namemap map. */
+ ref = xzalloc(sizeof *ref);
+ ref->name = xstrdup(label);
+ ref->offset = encode_offset;
+ hmap_insert(&namemap, &ref->node, label_hash);
+
+ uint8_t len = strlen(label);
+ memcpy(dns_encoded + encode_offset, &len, sizeof(uint8_t));
+ encode_offset += sizeof(uint8_t);
+ memcpy(dns_encoded + encode_offset, label, len);
+ encode_offset += len;
+ }
+ }
+ /* Add the end marker (0 byte) to determine the end of the
+ * domain. */
+ if (label == NULL) {
+ uint8_t end = 0;
+ memcpy(dns_encoded + encode_offset, &end, sizeof(uint8_t));
+ encode_offset += sizeof(uint8_t);
+ }
+ }
+ opt_header[1] = encode_offset;
+ ofpbuf_put(ofpacts, dns_encoded, encode_offset);
+
+ out:
+ HMAP_FOR_EACH_POP (ref, node, &namemap) {
+ free(ref->name);
+ free(ref);
+ }
+ hmap_destroy(&namemap);
+ free(domain_list);
+ free(dns_encoded);
}
}
diff --git a/lib/ovn-l7.h b/lib/ovn-l7.h
index 38555db..f34bc0d 100644
--- a/lib/ovn-l7.h
+++ b/lib/ovn-l7.h
@@ -34,6 +34,7 @@ struct gen_opts_map {
size_t code;
};
+#define DOMAIN_NAME_MAX_LEN 255
#define DHCP_BROADCAST_FLAG 0x8000
#define DHCP_OPTION(NAME, CODE, TYPE) \
@@ -81,6 +82,8 @@ struct gen_opts_map {
#define DHCP_OPT_PATH_PREFIX DHCP_OPTION("path_prefix", 210, "str")
#define DHCP_OPT_TFTP_SERVER_ADDRESS \
DHCP_OPTION("tftp_server_address", 150, "ipv4")
+#define DHCP_OPT_DOMAIN_SEARCH_LIST \
+ DHCP_OPTION("domain_search_list", 119, "domains")
#define DHCP_OPT_ARP_CACHE_TIMEOUT \
DHCP_OPTION("arp_cache_timeout", 35, "uint32")
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index ef08414..4ec2034 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -11336,6 +11336,7 @@ static struct gen_opts_map supported_dhcp_opts[] = {
DHCP_OPT_DOMAIN_NAME,
DHCP_OPT_ARP_CACHE_TIMEOUT,
DHCP_OPT_TCP_KEEPALIVE_INTERVAL,
+ DHCP_OPT_DOMAIN_SEARCH_LIST,
};
static struct gen_opts_map supported_dhcpv6_opts[] = {
diff --git a/ovn-sb.ovsschema b/ovn-sb.ovsschema
index 2ec729b..99c5de8 100644
--- a/ovn-sb.ovsschema
+++ b/ovn-sb.ovsschema
@@ -1,7 +1,7 @@
{
"name": "OVN_Southbound",
- "version": "2.8.1",
- "cksum": "236203406 21905",
+ "version": "2.8.2",
+ "cksum": "464326363 21916",
"tables": {
"SB_Global": {
"columns": {
@@ -218,7 +218,7 @@
"type": "string",
"enum": ["set", ["bool", "uint8", "uint16", "uint32",
"ipv4", "static_routes", "str",
- "host_id"]]}}}},
+ "host_id", "domains"]]}}}},
"isRoot": true},
"DHCPv6_Options": {
"columns": {
diff --git a/ovn-sb.xml b/ovn-sb.xml
index 208fb93..a6da80b 100644
--- a/ovn-sb.xml
+++ b/ovn-sb.xml
@@ -3232,6 +3232,17 @@ tcp.flags = RST;
</p>
</dd>
+ <dt><code>value: domains</code></dt>
+ <dd>
+ <p>
+ This indicates that the value of the DHCP option is a domain name
+ or a comma separated list of domain names.
+ </p>
+
+ <p>
+ Example. "name=domain_search_list", "code=119", "type=domains".
+ </p>
+ </dd>
</dl>
</column>
</table>
diff --git a/tests/ovn.at b/tests/ovn.at
index fa2592c..91ec564 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -1218,6 +1218,9 @@ reg0[15] = put_dhcp_opts(offerip=10.0.0.4,router=10.0.0.1,netmask=255.255.255.0,
reg0[15] = put_dhcp_opts(offerip=10.0.0.4,router=10.0.0.1,netmask=255.255.255.0,mtu=1400,ip_forward_enable=1,default_ttl=121,dns_server={8.8.8.8,7.7.7.7},classless_static_route={30.0.0.0/24,10.0.0.4,40.0.0.0/16,10.0.0.6,0.0.0.0/0,10.0.0.1},ethernet_encap=1,router_discovery=0,tftp_server="tftp_server_test");
formats as reg0[15] = put_dhcp_opts(offerip = 10.0.0.4, router = 10.0.0.1, netmask = 255.255.255.0, mtu = 1400, ip_forward_enable = 1, default_ttl = 121, dns_server = {8.8.8.8, 7.7.7.7}, classless_static_route = {30.0.0.0/24, 10.0.0.4, 40.0.0.0/16, 10.0.0.6, 0.0.0.0/0, 10.0.0.1}, ethernet_encap = 1, router_discovery = 0, tftp_server = "tftp_server_test");
encodes as controller(userdata=00.00.00.02.00.00.00.00.00.01.de.10.00.00.00.6f.0a.00.00.04.03.04.0a.00.00.01.01.04.ff.ff.ff.00.1a.02.05.78.13.01.01.17.01.79.06.08.08.08.08.08.07.07.07.07.79.14.18.1e.00.00.0a.00.00.04.10.28.00.0a.00.00.06.00.0a.00.00.01.24.01.01.1f.01.00.42.10.74.66.74.70.5f.73.65.72.76.65.72.5f.74.65.73.74,pause)
+reg2[5] = put_dhcp_opts(offerip=10.0.0.4,router=10.0.0.1,netmask=255.255.254.0,mtu=1400,domain_name="ovn.org",wpad="https://example.org",bootfile_name="https://127.0.0.1/boot.ipxe",path_prefix="/tftpboot",domain_search_list="ovn.org,abc.ovn.org");
+ formats as reg2[5] = put_dhcp_opts(offerip = 10.0.0.4, router = 10.0.0.1, netmask = 255.255.254.0, mtu = 1400, domain_name = "ovn.org", wpad = "https://example.org", bootfile_name = "https://127.0.0.1/boot.ipxe", path_prefix = "/tftpboot", domain_search_list = "ovn.org,abc.ovn.org");
+ encodes as controller(userdata=00.00.00.02.00.00.00.00.00.01.de.10.00.00.00.25.0a.00.00.04.03.04.0a.00.00.01.01.04.ff.ff.fe.00.1a.02.05.78.0f.07.6f.76.6e.2e.6f.72.67.fc.13.68.74.74.70.73.3a.2f.2f.65.78.61.6d.70.6c.65.2e.6f.72.67.43.1b.68.74.74.70.73.3a.2f.2f.31.32.37.2e.30.2e.30.2e.31.2f.62.6f.6f.74.2e.69.70.78.65.d2.09.2f.74.66.74.70.62.6f.6f.74.77.0f.03.6f.76.6e.03.6f.72.67.00.03.61.62.63.c0.00,pause)
reg1[0..1] = put_dhcp_opts(offerip = 1.2.3.4, router = 10.0.0.1);
Cannot use 2-bit field reg1[0..1] where 1-bit field is required.
diff --git a/tests/test-ovn.c b/tests/test-ovn.c
index 4391694..b43f67f 100644
--- a/tests/test-ovn.c
+++ b/tests/test-ovn.c
@@ -189,6 +189,7 @@ create_gen_opts(struct hmap *dhcp_opts, struct hmap *dhcpv6_opts,
dhcp_opt_add(dhcp_opts, "tftp_server_address", 150, "ipv4");
dhcp_opt_add(dhcp_opts, "arp_cache_timeout", 35, "uint32");
dhcp_opt_add(dhcp_opts, "tcp_keepalive_interval", 38, "uint32");
+ dhcp_opt_add(dhcp_opts, "domain_search_list", 119, "domains");
/* DHCPv6 options. */
hmap_init(dhcpv6_opts);
--
1.8.3.1
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