common: Improve valid_domain and check correct return

Improvement for #218.

diff --git a/src/dhcp-common.c b/src/dhcp-common.c
index ef33d2466e47b35e1ce30e953409ee867255d360..679af243286ae237745094eaf7ace3c93a4cf25a 100644 (file)
--- a/src/dhcp-common.c
+++ b/src/dhcp-common.c
@@ -413,26 +413,23 @@ decode_rfc1035(char *out, size_t len, const uint8_t *p, size_t pl)
 }
 
 /* Check for a valid name as per RFC952 and RFC1123 section 2.1 */
-static int
+static ssize_t
 valid_domainname(char *lbl, int type)
 {
-       char *slbl, *lst;
+       char *slbl = lbl, *lst = NULL;
        unsigned char c;
-       int start, len, errset;
+       int len = 0;
+       bool start = true, errset = false;
 
        if (lbl == NULL || *lbl == '\0') {
                errno = EINVAL;
                return 0;
        }
 
-       slbl = lbl;
-       lst = NULL;
-       start = 1;
-       len = errset = 0;
        for (;;) {
                c = (unsigned char)*lbl++;
                if (c == '\0')
-                       return 1;
+                       return lbl - slbl - 1;
                if (c == ' ') {
                        if (lbl - 1 == slbl) /* No space at start */
                                break;
@@ -440,7 +437,7 @@ valid_domainname(char *lbl, int type)
                                break;
                        /* Skip to the next label */
                        if (!start) {
-                               start = 1;
+                               start = true;
                                lst = lbl - 1;
                        }
                        if (len)
@@ -459,13 +456,13 @@ valid_domainname(char *lbl, int type)
                {
                        if (++len > NS_MAXLABEL) {
                                errno = ERANGE;
-                               errset = 1;
+                               errset = true;
                                break;
                        }
                } else
                        break;
                if (start)
-                       start = 0;
+                       start = false;
        }
 
        if (!errset)
@@ -473,7 +470,7 @@ valid_domainname(char *lbl, int type)
        if (lst) {
                /* At least one valid domain, return it */
                *lst = '\0';
-               return 1;
+               return lst - slbl;
        }
        return 0;
 }
@@ -665,7 +662,7 @@ print_option(FILE *fp, const char *prefix, const struct dhcp_opt *opt,
                        goto err;
                if (sl == 0)
                        goto done;
-               if (valid_domainname(domain, opt->type) == -1)
+               if (!valid_domainname(domain, opt->type))
                        goto err;
                return efprintf(fp, "%s", domain);
        }