Merge pull request #28132 from rpigott/dhcp-captive-portal

Implement RFC8910: captive portal dhcp options

src/libsystemd-network/dhcp-lease-internal.h

@@ -60,6 +60,7 @@ struct sd_dhcp_lease {
         char **search_domains;
         char *hostname;
         char *root_path;
+        char *captive_portal;
 
         void *client_id;
         size_t client_id_len;

src/libsystemd-network/dhcp6-lease-internal.h

@@ -43,6 +43,7 @@ struct sd_dhcp6_lease {
         struct in6_addr *sntp;
         size_t sntp_count;
         char *fqdn;
+        char *captive_portal;
 };
 
 int dhcp6_lease_get_lifetime(sd_dhcp6_lease *lease, usec_t *ret_t1, usec_t *ret_t2, usec_t *ret_valid);
@@ -60,6 +61,7 @@ int dhcp6_lease_add_domains(sd_dhcp6_lease *lease, const uint8_t *optval, size_t
 int dhcp6_lease_add_ntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 int dhcp6_lease_add_sntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
+int dhcp6_lease_set_captive_portal(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 
 int dhcp6_lease_new(sd_dhcp6_lease **ret);
 int dhcp6_lease_new_from_message(

src/libsystemd-network/dhcp6-option.c

@@ -524,6 +524,26 @@ int dhcp6_option_parse_status(const uint8_t *data, size_t data_len, char **ret_s
         return status;
 }
 
+/* parse a string from dhcp option field. *ret must be initialized */
+int dhcp6_option_parse_string(const uint8_t *data, size_t data_len, char **ret) {
+        _cleanup_free_ char *string = NULL;
+        int r;
+
+        assert(data);
+        assert(ret);
+
+        if (data_len <= 0) {
+                *ret = mfree(*ret);
+                return 0;
+        }
+
+        r = make_cstring((const char *) data, data_len, MAKE_CSTRING_REFUSE_TRAILING_NUL, &string);
+        if (r < 0)
+                return r;
+
+        return free_and_replace(*ret, string);
+}
+
 static int dhcp6_option_parse_ia_options(sd_dhcp6_client *client, const uint8_t *buf, size_t buflen) {
         int r;
 

src/libsystemd-network/dhcp6-option.h

@@ -88,6 +88,7 @@ int dhcp6_option_parse(
                 size_t *ret_option_data_len,
                 const uint8_t **ret_option_data);
 int dhcp6_option_parse_status(const uint8_t *data, size_t data_len, char **ret_status_message);
+int dhcp6_option_parse_string(const uint8_t *data, size_t data_len, char **ret);
 int dhcp6_option_parse_ia(
                 sd_dhcp6_client *client,
                 be32_t iaid,

src/libsystemd-network/ndisc-router.c

@@ -715,3 +715,45 @@ int sd_ndisc_router_dnssl_get_lifetime(sd_ndisc_router *rt, uint32_t *ret_sec) {
         *ret_sec = be32toh(*(uint32_t*) (ri + 4));
         return 0;
 }
+
+int sd_ndisc_router_captive_portal_get_uri(sd_ndisc_router *rt, const char **ret_uri, size_t *ret_size) {
+        int r;
+        const char *nd_opt_captive_portal;
+        size_t length;
+
+        assert_return(rt, -EINVAL);
+        assert_return(ret_uri, -EINVAL);
+
+        r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_CAPTIVE_PORTAL);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EMEDIUMTYPE;
+
+        r = sd_ndisc_router_option_get_raw(rt, (void *)&nd_opt_captive_portal, &length);
+        if (r < 0)
+                return r;
+
+        /* The length field has units of 8 octets */
+        assert(length % 8 == 0);
+        if (length == 0)
+                return -EBADMSG;
+
+        /* Check that the message is not truncated by an embedded NUL.
+         * NUL padding to a multiple of 8 is expected. */
+        size_t size = strnlen(nd_opt_captive_portal + 2, length - 2);
+        if (DIV_ROUND_UP(size + 2, 8) != length / 8)
+                return -EBADMSG;
+
+        /* Let's not return an empty buffer */
+        if (size == 0) {
+                *ret_uri = NULL;
+                *ret_size = 0;
+                return 0;
+        }
+
+        *ret_uri = nd_opt_captive_portal + 2;
+        *ret_size = size;
+
+        return 0;
+}

src/libsystemd-network/sd-dhcp-lease.c

@@ -168,6 +168,17 @@ int sd_dhcp_lease_get_root_path(sd_dhcp_lease *lease, const char **root_path) {
         return 0;
 }
 
+int sd_dhcp_lease_get_captive_portal(sd_dhcp_lease *lease, const char **ret) {
+        assert_return(lease, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!lease->captive_portal)
+                return -ENODATA;
+
+        *ret = lease->captive_portal;
+        return 0;
+}
+
 int sd_dhcp_lease_get_router(sd_dhcp_lease *lease, const struct in_addr **addr) {
         assert_return(lease, -EINVAL);
         assert_return(addr, -EINVAL);
@@ -322,6 +333,7 @@ static sd_dhcp_lease *dhcp_lease_free(sd_dhcp_lease *lease) {
         free(lease->timezone);
         free(lease->hostname);
         free(lease->domainname);
+        free(lease->captive_portal);
 
         for (sd_dhcp_lease_server_type_t i = 0; i < _SD_DHCP_LEASE_SERVER_TYPE_MAX; i++)
                 free(lease->servers[i].addr);
@@ -406,6 +418,22 @@ static int lease_parse_domain(const uint8_t *option, size_t len, char **ret) {
         return 0;
 }
 
+static int lease_parse_captive_portal(const uint8_t *option, size_t len, char **ret) {
+        _cleanup_free_ char *uri = NULL;
+        int r;
+
+        assert(option);
+        assert(ret);
+
+        r = dhcp_option_parse_string(option, len, &uri);
+        if (r < 0)
+                return r;
+        if (uri && !in_charset(uri, URI_VALID))
+                return -EINVAL;
+
+        return free_and_replace(*ret, uri);
+}
+
 static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *n_ret) {
         assert(option || len == 0);
         assert(ret);
@@ -675,6 +703,12 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void
                         log_debug_errno(r, "Failed to parse LPR server, ignoring: %m");
                 break;
 
+        case SD_DHCP_OPTION_DHCP_CAPTIVE_PORTAL:
+                r = lease_parse_captive_portal(option, len, &lease->captive_portal);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse captive portal, ignoring: %m");
+                break;
+
         case SD_DHCP_OPTION_STATIC_ROUTE:
                 r = lease_parse_static_routes(lease, option, len);
                 if (r < 0)

src/libsystemd-network/sd-dhcp6-lease.c

@@ -445,6 +445,34 @@ int sd_dhcp6_lease_get_fqdn(sd_dhcp6_lease *lease, const char **ret) {
         return 0;
 }
 
+int dhcp6_lease_set_captive_portal(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen) {
+        _cleanup_free_ char *uri = NULL;
+        int r;
+
+        assert(lease);
+        assert(optval || optlen == 0);
+
+        r = dhcp6_option_parse_string(optval, optlen, &uri);
+        if (r < 0)
+                return r;
+
+        if (uri && !in_charset(uri, URI_VALID))
+                return -EINVAL;
+
+        return free_and_replace(lease->captive_portal, uri);
+}
+
+int sd_dhcp6_lease_get_captive_portal(sd_dhcp6_lease *lease, const char **ret) {
+        assert_return(lease, -EINVAL);
+        assert_return(ret, -EINVAL);
+
+        if (!lease->captive_portal)
+                return -ENODATA;
+
+        *ret = lease->captive_portal;
+        return 0;
+}
+
 static int dhcp6_lease_parse_message(
                 sd_dhcp6_client *client,
                 sd_dhcp6_lease *lease,
@@ -610,6 +638,12 @@ static int dhcp6_lease_parse_message(
 
                         break;
 
+                case SD_DHCP6_OPTION_CAPTIVE_PORTAL:
+                        r = dhcp6_lease_set_captive_portal(lease, optval, optlen);
+                        if (r < 0)
+                                log_dhcp6_client_errno(client, r, "Failed to parse captive portal option, ignoring: %m");
+                        break;
+
                 case SD_DHCP6_OPTION_CLIENT_FQDN:
                         r = dhcp6_lease_set_fqdn(lease, optval, optlen);
                         if (r < 0)
@@ -670,6 +704,7 @@ static sd_dhcp6_lease *dhcp6_lease_free(sd_dhcp6_lease *lease) {
         dhcp6_ia_free(lease->ia_pd);
         free(lease->dns);
         free(lease->fqdn);
+        free(lease->captive_portal);
         strv_free(lease->domains);
         free(lease->ntp);
         strv_free(lease->ntp_fqdn);