libxtables: Fix guided option parser for use with arptables

With an unexpected value in afinfo->family, guided option parser was
rather useless when called from arptables extensions. Introduce
afinfo_family() wrapper to sanitize at least NFPROTO_ARP value.

Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/libxtables/xtoptions.c b/libxtables/xtoptions.c
index 0667315ceccf89b26d9deeeda4cfb83c693e6acb..25540f8b88c6da9e3c4da9975b71454210aec542 100644 (file)
--- a/libxtables/xtoptions.c
+++ b/libxtables/xtoptions.c
@@ -65,6 +65,19 @@ static const size_t xtopt_psize[] = {
        [XTTYPE_ETHERMAC]    = sizeof(uint8_t[6]),
 };
 
+/**
+ * Return a sanitized afinfo->family value, covering for NFPROTO_ARP
+ */
+static uint8_t afinfo_family(void)
+{
+       switch (afinfo->family) {
+       case NFPROTO_ARP:
+               return NFPROTO_IPV4;
+       default:
+               return afinfo->family;
+       }
+}
+
 /**
  * Creates getopt options from the x6-style option map, and assigns each a
  * getopt id.
@@ -461,7 +474,7 @@ static socklen_t xtables_sa_hostlen(unsigned int afproto)
  */
 static void xtopt_parse_host(struct xt_option_call *cb)
 {
-       struct addrinfo hints = {.ai_family = afinfo->family};
+       struct addrinfo hints = {.ai_family = afinfo_family()};
        unsigned int adcount = 0;
        struct addrinfo *res, *p;
        int ret;
@@ -472,7 +485,7 @@ static void xtopt_parse_host(struct xt_option_call *cb)
                        "getaddrinfo: %s\n", gai_strerror(ret));
 
        memset(&cb->val.hmask, 0xFF, sizeof(cb->val.hmask));
-       cb->val.hlen = (afinfo->family == NFPROTO_IPV4) ? 32 : 128;
+       cb->val.hlen = (afinfo_family() == NFPROTO_IPV4) ? 32 : 128;
 
        for (p = res; p != NULL; p = p->ai_next) {
                if (adcount == 0) {
@@ -615,7 +628,7 @@ static void xtopt_parse_mport(struct xt_option_call *cb)
 
 static int xtopt_parse_mask(struct xt_option_call *cb)
 {
-       struct addrinfo hints = {.ai_family = afinfo->family,
+       struct addrinfo hints = {.ai_family = afinfo_family(),
                                 .ai_flags = AI_NUMERICHOST };
        struct addrinfo *res;
        int ret;
@@ -627,7 +640,7 @@ static int xtopt_parse_mask(struct xt_option_call *cb)
        memcpy(&cb->val.hmask, xtables_sa_host(res->ai_addr, res->ai_family),
               xtables_sa_hostlen(res->ai_family));
 
-       switch(afinfo->family) {
+       switch(afinfo_family()) {
        case AF_INET:
                cb->val.hlen = xtables_ipmask_to_cidr(&cb->val.hmask.in);
                break;
@@ -649,7 +662,7 @@ static void xtopt_parse_plen(struct xt_option_call *cb)
        const struct xt_option_entry *entry = cb->entry;
        unsigned int prefix_len = 128; /* happiness is a warm gcc */
 
-       cb->val.hlen = (afinfo->family == NFPROTO_IPV4) ? 32 : 128;
+       cb->val.hlen = (afinfo_family() == NFPROTO_IPV4) ? 32 : 128;
        if (!xtables_strtoui(cb->arg, NULL, &prefix_len, 0, cb->val.hlen)) {
                /* Is this mask expressed in full format? e.g. 255.255.255.0 */
                if (xtopt_parse_mask(cb))