extensions: ipt_DNAT: Merge v1/v2 print/save code

Turn print_range() function into sprint_range() so it becomes more
versatile. Make it accept the new nf_nat_range2 data structure and
make v1 callers convert their nf_nat_ipv4_multi_range_compat structs
to that.
This allows to introduce an inner __DNAT_print() which acts for v1 and
v2 and prints either 'print' or 'save' syntax.

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

diff --git a/extensions/libipt_DNAT.c b/extensions/libipt_DNAT.c
index 2a7b1bc4ec0a6e04a2b0b4c43cdc6354b25079ad..b72437d5e92f28f8e246ed8a1d753ccd9fa5baf3 100644 (file)
--- a/extensions/libipt_DNAT.c
+++ b/extensions/libipt_DNAT.c
@@ -9,6 +9,15 @@
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter/nf_nat.h>
 
+#define TO_IPV4_MRC(ptr) ((const struct nf_nat_ipv4_multi_range_compat *)(ptr))
+#define RANGE2_INIT_FROM_IPV4_MRC(ptr) {                       \
+       .flags          = TO_IPV4_MRC(ptr)->range[0].flags,     \
+       .min_addr.ip    = TO_IPV4_MRC(ptr)->range[0].min_ip,    \
+       .max_addr.ip    = TO_IPV4_MRC(ptr)->range[0].max_ip,    \
+       .min_proto      = TO_IPV4_MRC(ptr)->range[0].min,       \
+       .max_proto      = TO_IPV4_MRC(ptr)->range[0].max,       \
+};
+
 enum {
        O_TO_DEST = 0,
        O_RANDOM,
@@ -206,51 +215,55 @@ static void DNAT_fcheck(struct xt_fcheck_call *cb)
                              "Shifted portmap ranges not supported with this kernel");
 }
 
-static void print_range(const struct nf_nat_ipv4_range *r)
+static char *sprint_range(const struct nf_nat_range2 *r)
 {
-       if (r->flags & NF_NAT_RANGE_MAP_IPS) {
-               struct in_addr a;
+       static char buf[INET_ADDRSTRLEN * 2 + 1 + 6 * 3];
 
-               a.s_addr = r->min_ip;
-               printf("%s", xtables_ipaddr_to_numeric(&a));
-               if (r->max_ip != r->min_ip) {
-                       a.s_addr = r->max_ip;
-                       printf("-%s", xtables_ipaddr_to_numeric(&a));
-               }
+       if (r->flags & NF_NAT_RANGE_MAP_IPS) {
+               sprintf(buf, "%s", xtables_ipaddr_to_numeric(&r->min_addr.in));
+               if (memcmp(&r->min_addr, &r->max_addr, sizeof(r->min_addr)))
+                       sprintf(buf + strlen(buf), "-%s",
+                               xtables_ipaddr_to_numeric(&r->max_addr.in));
+       } else {
+               buf[0] = '\0';
        }
        if (r->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
-               printf(":");
-               printf("%hu", ntohs(r->min.tcp.port));
-               if (r->max.tcp.port != r->min.tcp.port)
-                       printf("-%hu", ntohs(r->max.tcp.port));
+               sprintf(buf + strlen(buf), ":%hu",
+                       ntohs(r->min_proto.tcp.port));
+               if (r->max_proto.tcp.port != r->min_proto.tcp.port)
+                       sprintf(buf + strlen(buf), "-%hu",
+                               ntohs(r->max_proto.tcp.port));
+               if (r->flags & NF_NAT_RANGE_PROTO_OFFSET)
+                       sprintf(buf + strlen(buf), "/%hu",
+                               ntohs(r->base_proto.tcp.port));
        }
+       return buf;
+}
+
+static void __DNAT_print(const struct nf_nat_range2 *r, bool save)
+{
+       const char *dashdash = save ? "--" : "";
+
+       printf(" %s%s", save ? "--to-destination " : "to:", sprint_range(r));
+       if (r->flags & NF_NAT_RANGE_PROTO_RANDOM)
+               printf(" %srandom", dashdash);
+       if (r->flags & NF_NAT_RANGE_PERSISTENT)
+               printf(" %spersistent", dashdash);
 }
 
 static void DNAT_print(const void *ip, const struct xt_entry_target *target,
                        int numeric)
 {
-       const struct nf_nat_ipv4_multi_range_compat *mr =
-                               (const void *)target->data;
-
-       printf(" to:");
-       print_range(mr->range);
-       if (mr->range->flags & NF_NAT_RANGE_PROTO_RANDOM)
-               printf(" random");
-       if (mr->range->flags & NF_NAT_RANGE_PERSISTENT)
-               printf(" persistent");
+       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
+
+       __DNAT_print(&range, false);
 }
 
 static void DNAT_save(const void *ip, const struct xt_entry_target *target)
 {
-       const struct nf_nat_ipv4_multi_range_compat *mr =
-                               (const void *)target->data;
-
-       printf(" --to-destination ");
-       print_range(mr->range);
-       if (mr->range->flags & NF_NAT_RANGE_PROTO_RANDOM)
-               printf(" --random");
-       if (mr->range->flags & NF_NAT_RANGE_PERSISTENT)
-               printf(" --persistent");
+       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
+
+       __DNAT_print(&range, true);
 }
 
 static void print_range_xlate(const struct nf_nat_ipv4_range *r,
@@ -312,47 +325,15 @@ static void DNAT_fcheck_v2(struct xt_fcheck_call *cb)
                range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
 }
 
-static void print_range_v2(const struct nf_nat_range2 *range)
-{
-       if (range->flags & NF_NAT_RANGE_MAP_IPS) {
-               printf("%s", xtables_ipaddr_to_numeric(&range->min_addr.in));
-               if (memcmp(&range->min_addr, &range->max_addr,
-                          sizeof(range->min_addr)))
-                       printf("-%s", xtables_ipaddr_to_numeric(&range->max_addr.in));
-       }
-       if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
-               printf(":");
-               printf("%hu", ntohs(range->min_proto.tcp.port));
-               if (range->max_proto.tcp.port != range->min_proto.tcp.port)
-                       printf("-%hu", ntohs(range->max_proto.tcp.port));
-               if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
-                       printf("/%hu", ntohs(range->base_proto.tcp.port));
-       }
-}
-
 static void DNAT_print_v2(const void *ip, const struct xt_entry_target *target,
                        int numeric)
 {
-       const struct nf_nat_range2 *range = (const void *)target->data;
-
-       printf(" to:");
-       print_range_v2(range);
-       if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
-               printf(" random");
-       if (range->flags & NF_NAT_RANGE_PERSISTENT)
-               printf(" persistent");
+       __DNAT_print((const void *)target->data, false);
 }
 
 static void DNAT_save_v2(const void *ip, const struct xt_entry_target *target)
 {
-       const struct nf_nat_range2 *range = (const void *)target->data;
-
-       printf(" --to-destination ");
-       print_range_v2(range);
-       if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
-               printf(" --random");
-       if (range->flags & NF_NAT_RANGE_PERSISTENT)
-               printf(" --persistent");
+       __DNAT_print((const void *)target->data, true);
 }
 
 static void print_range_xlate_v2(const struct nf_nat_range2 *range,