Added service hash for resolving port/protocol numbers to names.

Minor fix to handling of netmasks end /32.

serv_hash.c

@@ -0,0 +1,66 @@
+/* hash table */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <netdb.h>
+#include "serv_hash.h"
+#include "hash.h"
+#include "iftop.h"
+
+// Deliberately not a power of 2 or 10
+#define hash_table_size 123
+
+int serv_hash_compare(void* a, void* b) {
+    ip_service* aa = (ip_service*)a;
+    ip_service* bb = (ip_service*)b;
+    return (aa->port == bb->port &&
+            aa->protocol == bb->protocol);
+}
+
+int serv_hash_hash(void* key) {
+    ip_service* serv = (ip_service*)key;
+    return serv->protocol;
+}
+
+void* serv_hash_copy_key(void* orig) {
+    ip_service* copy;
+    copy = xmalloc(sizeof *copy);
+    *copy = *(ip_service*)orig;
+    return copy;
+}
+
+void serv_hash_delete_key(void* key) {
+    free(key);
+}
+
+/*
+ * Allocate and return a hash
+ */
+hash_type* serv_hash_create() {
+    hash_type* hash_table;
+    hash_table = xcalloc(hash_table_size, sizeof *hash_table);
+    hash_table->size = hash_table_size;
+    hash_table->compare = &serv_hash_compare;
+    hash_table->hash = &serv_hash_hash;
+    hash_table->delete_key = &serv_hash_delete_key;
+    hash_table->copy_key = &serv_hash_copy_key;
+    hash_initialise(hash_table);
+    return hash_table;
+}
+
+void serv_hash_initialise(hash_type* sh) {
+  struct servent* ent;
+  struct protoent* pent;
+  ip_service* service;
+  setprotoent(1);
+  while((ent = getservent()) != NULL) {
+    pent = getprotobyname(ent->s_proto);
+    if(pent != NULL) {
+      service = xmalloc(sizeof(ip_service));
+      service->port = ntohs(ent->s_port);
+      service->protocol = pent->p_proto;
+      hash_insert(sh, service, xstrdup(ent->s_name));
+    }
+  }
+  endprotoent();
+}