rearrange and cleanup

diff --git a/src/protocols/dhcpv4/decode.c b/src/protocols/dhcpv4/decode.c
index 3dc89dafe11fe16795fbb5d36674551ff3a1d33f..f86a28e343e8853d7f8d37c33d7cc6451fed03eb 100644 (file)
--- a/src/protocols/dhcpv4/decode.c
+++ b/src/protocols/dhcpv4/decode.c
@@ -214,44 +214,45 @@ static ssize_t decode_value(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t
 
                if (da_is_bits_prefix(vp->da)) {
                        uint32_t ipaddr, mask;
+                       size_t needs;
 
                        if ((data_len == 0) || (*p > 32)) goto raw;
 
-                       if (exact && (data_len > 5)) goto raw;
+                       needs = 1 + ((*p + 0x07) >> 3);
+                       if (data_len < needs) goto raw;
+                       if (exact && (data_len > needs)) goto raw;
 
                        vp->vp_ip.prefix = *p;
-                       mask = ~(uint32_t) 0;
-                       mask <<= (32 - vp->vp_ip.prefix);
 
-                       if (*p > 24) {
-                               if (data_len < 5) goto raw;
-                               ipaddr = fr_net_to_uint32(p + 1);
-                               p += 5;
-
-                       } else if (*p > 16) {
-                               if (data_len < 4) goto raw;
-                               ipaddr = fr_net_to_uint24(p + 1);
-                               ipaddr <<= 8;
-                               p += 4;
-
-                       } else if (*p > 8) {
-                               if (data_len < 3) goto raw;
-                               ipaddr = fr_net_to_uint16(p + 1);
-                               ipaddr <<= 16;
-                               p += 3;
-
-                       } else if (*p > 0) {
-                               if (data_len < 2) goto raw;
-                               ipaddr = p[1];
-                               ipaddr <<= 24;
-                               p += 2;
-
-                       } else {
-                               p++;
+                       /*
+                        *      If the IP address is longer than necessary, then only grab the pieces we need.
+                        */
+                       if (vp->vp_ip.prefix) {
+                               mask = ~(uint32_t) 0;
+                               mask <<= (32 - vp->vp_ip.prefix);
+
+                               if (*p > 24) {
+                                       ipaddr = fr_net_to_uint32(p + 1);
+
+                               } else if (*p > 16) {
+                                       ipaddr = fr_net_to_uint24(p + 1);
+                                       ipaddr <<= 8;
+
+                               } else if (*p > 8) {
+                                       ipaddr = fr_net_to_uint16(p + 1);
+                                       ipaddr <<= 16;
+
+                               } else { /* 1..8 */
+                                       ipaddr = p[1];
+                                       ipaddr <<= 24;
+                               }
+                       } else { /* prefix == 0 */
                                ipaddr = 0;
+                               mask = 0;
                        }
 
                        vp->vp_ipv4addr = htonl(ipaddr & mask);
+                       p += needs;
                        break;
                }