dhcpv6: dhcpv6_handle_advert; migrate if blocks to switch case

reduces branching

Signed-off-by: Paul Donald <[email protected]>
Link: https://github.com/openwrt/odhcp6c/pull/118
Signed-off-by: Álvaro Fernández Rojas <[email protected]>

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 0e4d1ed497ef9c2e9b4ae62d3aa6b515ae92b2cc..fc77fc804b5ca43e4a797ee8ab27bfcd9f148116 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -1188,51 +1188,78 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
                        dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr), NULL);
                }
 
-               if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
-                       memcpy(cand.duid, odata, olen);
-                       cand.duid_len = olen;
-               } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
-                               cand.preference >= 0) {
-                       cand.preference = pref = odata[0];
-               } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
-                       if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
+               switch (otype) {
+               case DHCPV6_OPT_SERVERID:
+                       if (olen <= 130) {
+                               memcpy(cand.duid, odata, olen);
+                               cand.duid_len = olen;
+                       }
+                       break;
+
+               case DHCPV6_OPT_PREF:
+                       if (olen >= 1 && cand.preference >= 0)
+                               cand.preference = pref = odata[0];
+                       break;
+
+               case DHCPV6_OPT_UNICAST:
+                       if (olen == sizeof(cand.server_addr) &&
+                           !(client_options & DHCPV6_IGNORE_OPT_UNICAST))
                                cand.server_addr = *(struct in6_addr *)odata;
+                       break;
 
-               } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
+               case DHCPV6_OPT_RECONF_ACCEPT:
                        cand.wants_reconfigure = true;
-               } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
-                       uint32_t sol_max_rt = ntohl_unaligned(odata);
-                       if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
-                                       sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
-                               cand.sol_max_rt = sol_max_rt;
-
-               } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
-                       uint32_t inf_max_rt = ntohl_unaligned(odata);
-                       if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
-                                       inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
-                               cand.inf_max_rt = inf_max_rt;
-
-               } else if (otype == DHCPV6_OPT_IA_PD &&
-                                       olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
-                       struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
-                       uint8_t *oend = odata + olen, *d;
-                       dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
-                               if (otype == DHCPV6_OPT_IA_PREFIX &&
-                                               olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
-                                       struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
-                                       have_pd = p->prefix;
+                       break;
+
+               case DHCPV6_OPT_SOL_MAX_RT:
+                       if (olen == 4) {
+                               uint32_t sol_max_rt = ntohl_unaligned(odata);
+                               if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
+                                   sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
+                                       cand.sol_max_rt = sol_max_rt;
+                       }
+                       break;
+
+               case DHCPV6_OPT_INF_MAX_RT:
+                       if (olen == 4) {
+                               uint32_t inf_max_rt = ntohl_unaligned(odata);
+                               if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
+                                   inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
+                                       cand.inf_max_rt = inf_max_rt;
+                       }
+                       break;
+
+               case DHCPV6_OPT_IA_PD:
+                       if (olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
+                               struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr *)&odata[-4];
+                               uint8_t *oend = odata + olen, *d;
+
+                               dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
+                                       if (otype == DHCPV6_OPT_IA_PREFIX &&
+                                           olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
+                                               struct dhcpv6_ia_prefix *p =
+                                                       (struct dhcpv6_ia_prefix *)&d[-4];
+                                               have_pd = p->prefix;
+                                       }
                                }
                        }
-               } else if (otype == DHCPV6_OPT_IA_NA &&
-                                       olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
-                       struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
-                       uint8_t *oend = odata + olen, *d;
-
-                       dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
-                               if (otype == DHCPV6_OPT_IA_ADDR &&
-                                               olen >= -4 + sizeof(struct dhcpv6_ia_addr))
-                                       have_na = true;
+                       break;
+
+               case DHCPV6_OPT_IA_NA:
+                       if (olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
+                               struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr *)&odata[-4];
+                               uint8_t *oend = odata + olen, *d;
+
+                               dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
+                                       if (otype == DHCPV6_OPT_IA_ADDR &&
+                                           olen >= -4 + sizeof(struct dhcpv6_ia_addr))
+                                               have_na = true;
+                               }
                        }
+                       break;
+
+               default:
+                       break;
                }
        }