treewide: Remove unnecessary strlen() calls.

In many cases OVN components are using strlen() to check if the string
is not empty.  In that case, unnecessary scan of the whole string is
performed and the length is calculated, while it's enough to just check
the first byte.

Some functions also have completely unnecessary strlen() calls where
needed functionality can be achieved without them.

The most impactful changes in this commit are around extract_addresses()
function, and extract_lsp_addresses() in particular.  It is called by
northd for every logical port and involves 2 unnecessary strlen() calls.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>

controller/chassis.c

@@ -99,9 +99,9 @@ static const char *
 get_hostname(const struct smap *ext_ids, const char *chassis_id)
 {
     const char *hostname = get_chassis_external_id_value(ext_ids, chassis_id,
-                                                         "hostname", "");
+                                                         "hostname", NULL);
 
-    if (strlen(hostname) == 0) {
+    if (!hostname) {
         static char hostname_[HOST_NAME_MAX + 1];
 
         if (gethostname(hostname_, sizeof(hostname_))) {

controller/encaps.c

@@ -77,7 +77,7 @@ tunnel_create_name(struct tunnel_ctx *tc, const char *chassis_id)
     for (int i = 0; i < UINT16_MAX; i++) {
         const char *idx = get_chassis_idx(tc->ovs_table);
         char *port_name = xasprintf(
-            "ovn%s-%.*s-%x", idx, strlen(idx) ? 5 : 6, chassis_id, i);
+            "ovn%s-%.*s-%x", idx, idx[0] ? 5 : 6, chassis_id, i);
 
         if (!sset_contains(&tc->port_names, port_name)) {
             return port_name;

controller/physical.c

@@ -505,7 +505,7 @@ populate_remote_chassis_macs(const struct sbrec_chassis *my_chassis,
         const char *tokens
             = get_chassis_mac_mappings(&chassis->other_config, chassis->name);
 
-        if (!strlen(tokens)) {
+        if (!tokens[0]) {
             continue;
         }
 

controller/pinctrl.c

@@ -3775,12 +3775,12 @@ ipv6_ra_update_config(const struct sbrec_port_binding *pb)
 
     const char *dnssl = smap_get(&pb->options, "ipv6_ra_dnssl");
     if (dnssl) {
-        ds_put_buffer(&config->dnssl, dnssl, strlen(dnssl));
+        ds_put_cstr(&config->dnssl, dnssl);
     }
 
     const char *route_info = smap_get(&pb->options, "ipv6_ra_route_info");
     if (route_info) {
-        ds_put_buffer(&config->route_info, route_info, strlen(route_info));
+        ds_put_cstr(&config->route_info, route_info);
     }
 
     return config;
@@ -5825,7 +5825,7 @@ extract_addresses_with_port(const char *addresses,
     int ofs;
     if (!extract_addresses(addresses, laddrs, &ofs)) {
         return false;
-    } else if (ofs >= strlen(addresses)) {
+    } else if (!addresses[ofs]) {
         return true;
     }
 

ic/ovn-ic.c

@@ -1162,7 +1162,7 @@ add_static_to_routes_ad(
             ipv6_format_addr(&nexthop, &msg);
         }
 
-        ds_put_format(&msg, ", route_table: %s", strlen(nb_route->route_table)
+        ds_put_format(&msg, ", route_table: %s", nb_route->route_table[0]
                                                  ? nb_route->route_table
                                                  : "<main>");
 
@@ -1348,7 +1348,7 @@ sync_learned_routes(struct ic_context *ctx,
                 continue;
             }
 
-            if (strlen(isb_route->route_table) &&
+            if (isb_route->route_table[0] &&
                 strcmp(isb_route->route_table, ts_route_table)) {
                 if (VLOG_IS_DBG_ENABLED()) {
                     VLOG_DBG("Skip learning static route %s -> %s as either "

lib/ovn-util.c

@@ -128,7 +128,6 @@ parse_and_store_addresses(const char *address, struct lport_addresses *laddrs,
     const char *buf = address;
     const char *const start = buf;
     int buf_index = 0;
-    const char *buf_end = buf + strlen(address);
 
     if (extract_eth_addr) {
         if (!ovs_scan_len(buf, &buf_index, ETH_ADDR_SCAN_FMT,
@@ -151,7 +150,7 @@ parse_and_store_addresses(const char *address, struct lport_addresses *laddrs,
      * and store in the 'laddrs'. Break the loop if invalid data is found.
      */
     buf += buf_index;
-    while (buf < buf_end) {
+    while (*buf != '\0') {
         buf_index = 0;
         error = ip_parse_cidr_len(buf, &buf_index, &ip4, &plen);
         if (!error) {
@@ -205,7 +204,7 @@ extract_lsp_addresses(const char *address, struct lport_addresses *laddrs)
     int ofs;
     bool success = extract_addresses(address, laddrs, &ofs);
 
-    if (success && ofs < strlen(address)) {
+    if (success && address[ofs]) {
         static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
         VLOG_INFO_RL(&rl, "invalid syntax '%s' in address", address);
     }

northd/northd.c

@@ -9624,7 +9624,7 @@ route_table_add(struct simap *route_tables, const char *route_table_name)
 static uint32_t
 get_route_table_id(struct simap *route_tables, const char *route_table_name)
 {
-    if (!route_table_name || !strlen(route_table_name)) {
+    if (!route_table_name || !route_table_name[0]) {
         return 0;
     }
 
@@ -9699,7 +9699,7 @@ parsed_routes_add(struct ovn_datapath *od, const struct hmap *ports,
     struct in6_addr nexthop;
     unsigned int plen;
     bool is_discard_route = !strcmp(route->nexthop, "discard");
-    bool valid_nexthop = strlen(route->nexthop) && !is_discard_route;
+    bool valid_nexthop = route->nexthop[0] && !is_discard_route;
     if (valid_nexthop) {
         if (!ip46_parse_cidr(route->nexthop, &nexthop, &plen)) {
             static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 1);
@@ -9990,7 +9990,7 @@ find_static_route_outport(struct ovn_datapath *od, const struct hmap *ports,
                          route->output_port, route->ip_prefix);
             return false;
         }
-        if (strlen(route->nexthop)) {
+        if (route->nexthop[0]) {
             lrp_addr_s = find_lrp_member_ip(out_port, route->nexthop);
         }
         if (!lrp_addr_s) {
@@ -10022,7 +10022,7 @@ find_static_route_outport(struct ovn_datapath *od, const struct hmap *ports,
                 continue;
             }
 
-            if (strlen(route->nexthop)) {
+            if (route->nexthop[0]) {
                 lrp_addr_s = find_lrp_member_ip(out_port, route->nexthop);
             }
             if (lrp_addr_s) {
@@ -10338,7 +10338,7 @@ add_route(struct hmap *lflows, struct ovn_datapath *od,
     } else {
         ds_put_format(&common_actions, REG_ECMP_GROUP_ID" = 0; %s = ",
                       is_ipv4 ? REG_NEXT_HOP_IPV4 : REG_NEXT_HOP_IPV6);
-        if (gateway && strlen(gateway)) {
+        if (gateway && gateway[0]) {
             ds_put_cstr(&common_actions, gateway);
         } else {
             ds_put_format(&common_actions, "ip%s.dst", is_ipv4 ? "4" : "6");

utilities/ovn-nbctl.c

@@ -4553,7 +4553,7 @@ nbctl_lr_route_add(struct ctl_context *ctx)
     }
 
 cleanup:
-    if (next_hop && strlen(next_hop)) {
+    if (next_hop && next_hop[0]) {
         free(next_hop);
     }
     free(prefix);
@@ -6590,12 +6590,12 @@ print_route(const struct nbrec_logical_router_static_route *route,
 
     if (!strcmp(route->nexthop, "discard")) {
         next_hop = xasprintf("discard");
-    } else if (strlen(route->nexthop)) {
+    } else if (route->nexthop[0]) {
         next_hop = normalize_prefix_str(route->nexthop);
     }
     ds_put_format(s, "%25s %25s", prefix, next_hop);
     free(prefix);
-    if (strlen(next_hop)) {
+    if (next_hop[0]) {
         free(next_hop);
     }
 
@@ -6734,8 +6734,8 @@ nbctl_lr_route_list(struct ctl_context *ctx)
         if (!i || (i > 0 && strcmp(route->route_table,
                                    ipv4_routes[i - 1].route->route_table))) {
             ds_put_format(&ctx->output, "%sRoute Table %s:\n", i ? "\n" : "",
-                          strlen(route->route_table) ? route->route_table
-                                                     : "<main>");
+                          route->route_table[0] ? route->route_table
+                                                : "<main>");
         }
 
         print_route(ipv4_routes[i].route, &ctx->output, ecmp);
@@ -6760,8 +6760,8 @@ nbctl_lr_route_list(struct ctl_context *ctx)
         if (!i || (i > 0 && strcmp(route->route_table,
                                    ipv6_routes[i - 1].route->route_table))) {
             ds_put_format(&ctx->output, "%sRoute Table %s:\n", i ? "\n" : "",
-                          strlen(route->route_table) ? route->route_table
-                                                     : "<main>");
+                          route->route_table[0] ? route->route_table
+                                                : "<main>");
         }
 
         print_route(ipv6_routes[i].route, &ctx->output, ecmp);