extensions: DNAT: Generate print, save and xlate callbacks

Each extension's callbacks follow the same scheme so introduce a
generator which accepts the specifics as parameter - including the
method to transform from per-extension data into struct nf_nat_range2.

Also move the different parser frontends and fcheck callbacks in one
spot for clarity.

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

diff --git a/extensions/libxt_DNAT.c b/extensions/libxt_DNAT.c
index 9b94062512c09d2828150f10f1609770c29f45c7..e53002541ee037ef82ec2ced15e2c231cee1168d 100644 (file)
--- a/extensions/libxt_DNAT.c
+++ b/extensions/libxt_DNAT.c
@@ -25,6 +25,14 @@
        .min_proto      = TO_IPV4_MRC(ptr)->range[0].min,       \
        .max_proto      = TO_IPV4_MRC(ptr)->range[0].max,       \
 };
+#define TO_NF_NAT_RANGE(ptr) ((const struct nf_nat_range *)(ptr))
+#define RANGE2_INIT_FROM_RANGE(ptr) {                          \
+       .flags          = TO_NF_NAT_RANGE(ptr)->flags,          \
+       .min_addr       = TO_NF_NAT_RANGE(ptr)->min_addr,       \
+       .max_addr       = TO_NF_NAT_RANGE(ptr)->max_addr,       \
+       .min_proto      = TO_NF_NAT_RANGE(ptr)->min_proto,      \
+       .max_proto      = TO_NF_NAT_RANGE(ptr)->max_proto,      \
+};
 
 enum {
        O_TO_DEST = 0,
@@ -256,6 +264,30 @@ static void DNAT_parse(struct xt_option_call *cb)
        }
 }
 
+static void DNAT_parse6(struct xt_option_call *cb)
+{
+       struct nf_nat_range2 range = RANGE2_INIT_FROM_RANGE(cb->data);
+       struct nf_nat_range *range_v1 = (void *)cb->data;
+       const struct ip6t_entry *entry = cb->xt_entry;
+
+       __DNAT_parse(cb, entry->ipv6.proto, &range, AF_INET6);
+       memcpy(range_v1, &range, sizeof(*range_v1));
+}
+
+static void DNAT_parse_v2(struct xt_option_call *cb)
+{
+       const struct ipt_entry *entry = cb->xt_entry;
+
+       __DNAT_parse(cb, entry->ip.proto, cb->data, AF_INET);
+}
+
+static void DNAT_parse6_v2(struct xt_option_call *cb)
+{
+       const struct ip6t_entry *entry = cb->xt_entry;
+
+       __DNAT_parse(cb, entry->ipv6.proto, cb->data, AF_INET6);
+}
+
 static void DNAT_fcheck(struct xt_fcheck_call *cb)
 {
        struct nf_nat_ipv4_multi_range_compat *mr = cb->data;
@@ -267,6 +299,15 @@ static void DNAT_fcheck(struct xt_fcheck_call *cb)
                              "Shifted portmap ranges not supported with this kernel");
 }
 
+static void DNAT_fcheck6(struct xt_fcheck_call *cb)
+{
+       struct nf_nat_range *range = (void *)cb->data;
+
+       if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
+               xtables_error(PARAMETER_PROBLEM,
+                             "Shifted portmap ranges not supported with this kernel");
+}
+
 static char *sprint_range(const struct nf_nat_range2 *r, int family)
 {
        bool brackets = family == AF_INET6 &&
@@ -317,25 +358,6 @@ static void __NAT_print(const struct nf_nat_range2 *r, int family,
        if (r->flags & NF_NAT_RANGE_PERSISTENT)
                printf(" %spersistent", flag_pfx);
 }
-#define __DNAT_print(r, family) __NAT_print(r, family, "to:", "", false)
-#define __DNAT_save(r, family) __NAT_print(r, family, "--to-destination ", "--", false)
-#define __REDIRECT_print(r) __NAT_print(r, AF_INET, "redir ports ", "", true)
-#define __REDIRECT_save(r) __NAT_print(r, AF_INET, "--to-ports ", "--", true)
-
-static void DNAT_print(const void *ip, const struct xt_entry_target *target,
-                       int numeric)
-{
-       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
-
-       __DNAT_print(&range, AF_INET);
-}
-
-static void DNAT_save(const void *ip, const struct xt_entry_target *target)
-{
-       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
-
-       __DNAT_save(&range, AF_INET);
-}
 
 static int
 __NAT_xlate(struct xt_xlate *xl, const struct nf_nat_range2 *r,
@@ -362,162 +384,46 @@ __NAT_xlate(struct xt_xlate *xl, const struct nf_nat_range2 *r,
        return 1;
 }
 
-static int DNAT_xlate(struct xt_xlate *xl,
-                     const struct xt_xlate_tg_params *params)
-{
-       struct nf_nat_range2 range =
-               RANGE2_INIT_FROM_IPV4_MRC(params->target->data);
-
-       return __NAT_xlate(xl, &range, AF_INET, "dnat");
-}
-
-static void DNAT_parse_v2(struct xt_option_call *cb)
-{
-       const struct ipt_entry *entry = cb->xt_entry;
-
-       __DNAT_parse(cb, entry->ip.proto, cb->data, AF_INET);
-}
-
-static void DNAT_print_v2(const void *ip, const struct xt_entry_target *target,
-                       int numeric)
-{
-       __DNAT_print((const void *)target->data, AF_INET);
-}
-
-static void DNAT_save_v2(const void *ip, const struct xt_entry_target *target)
-{
-       __DNAT_save((const void *)target->data, AF_INET);
-}
-
-static int DNAT_xlate_v2(struct xt_xlate *xl,
-                         const struct xt_xlate_tg_params *params)
-{
-       return __NAT_xlate(xl, (const void *)params->target->data,
-                          AF_INET, "dnat");
-}
-
-static void DNAT_parse6(struct xt_option_call *cb)
-{
-       const struct ip6t_entry *entry = cb->xt_entry;
-       struct nf_nat_range *range_v1 = (void *)cb->data;
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, range_v1, sizeof(*range_v1));
-       __DNAT_parse(cb, entry->ipv6.proto, &range, AF_INET6);
-       memcpy(range_v1, &range, sizeof(*range_v1));
-}
-
-static void DNAT_fcheck6(struct xt_fcheck_call *cb)
-{
-       struct nf_nat_range *range = (void *)cb->data;
-
-       if (range->flags & NF_NAT_RANGE_PROTO_OFFSET)
-               xtables_error(PARAMETER_PROBLEM,
-                             "Shifted portmap ranges not supported with this kernel");
+#define PSX_GEN(name, converter, family,                                       \
+               print_rangeopt, save_rangeopt, skip_colon, xlate)              \
+static void name##_print(const void *ip, const struct xt_entry_target *target, \
+                        int numeric)                                          \
+{                                                                              \
+       struct nf_nat_range2 range = converter(target->data);                  \
+                                                                              \
+       __NAT_print(&range, family, print_rangeopt, "", skip_colon);           \
+}                                                                              \
+static void name##_save(const void *ip, const struct xt_entry_target *target)  \
+{                                                                              \
+       struct nf_nat_range2 range = converter(target->data);                  \
+                                                                              \
+       __NAT_print(&range, family, save_rangeopt, "--", skip_colon);          \
+}                                                                              \
+static int name##_xlate(struct xt_xlate *xl,                                   \
+                       const struct xt_xlate_tg_params *params)               \
+{                                                                              \
+       struct nf_nat_range2 range = converter(params->target->data);          \
+                                                                              \
+       return __NAT_xlate(xl, &range, family, xlate);                         \
 }
 
-static void DNAT_print6(const void *ip, const struct xt_entry_target *target,
-                       int numeric)
-{
-       struct nf_nat_range2 range = {};
+PSX_GEN(DNAT, RANGE2_INIT_FROM_IPV4_MRC, \
+       AF_INET, "to:", "--to-destination ", false, "dnat")
 
-       memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range));
-       __DNAT_print(&range, AF_INET6);
-}
+PSX_GEN(DNATv2, *(struct nf_nat_range2 *), \
+       AF_INET, "to:", "--to-destination ", false, "dnat")
 
-static void DNAT_save6(const void *ip, const struct xt_entry_target *target)
-{
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range));
-       __DNAT_save(&range, AF_INET6);
-}
-
-static int DNAT_xlate6(struct xt_xlate *xl,
-                      const struct xt_xlate_tg_params *params)
-{
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, (const void *)params->target->data,
-              sizeof(struct nf_nat_range));
-       return __NAT_xlate(xl, &range, AF_INET6, "dnat");
-}
+PSX_GEN(DNAT6, RANGE2_INIT_FROM_RANGE, \
+       AF_INET6, "to:", "--to-destination ", false, "dnat")
 
-static void DNAT_parse6_v2(struct xt_option_call *cb)
-{
-       const struct ip6t_entry *entry = cb->xt_entry;
-
-       __DNAT_parse(cb, entry->ipv6.proto, cb->data, AF_INET6);
-}
+PSX_GEN(DNAT6v2, *(struct nf_nat_range2 *), \
+       AF_INET6, "to:", "--to-destination ", false, "dnat")
 
-static void DNAT_print6_v2(const void *ip, const struct xt_entry_target *target,
-                          int numeric)
-{
-       __DNAT_print((const void *)target->data, AF_INET6);
-}
+PSX_GEN(REDIRECT, RANGE2_INIT_FROM_IPV4_MRC, \
+       AF_INET, "redir ports ", "--to-ports ", true, "redirect")
 
-static void DNAT_save6_v2(const void *ip, const struct xt_entry_target *target)
-{
-       __DNAT_save((const void *)target->data, AF_INET6);
-}
-
-static int DNAT_xlate6_v2(struct xt_xlate *xl,
-                         const struct xt_xlate_tg_params *params)
-{
-       return __NAT_xlate(xl, (const void *)params->target->data,
-                          AF_INET6, "dnat");
-}
-
-static void REDIRECT_print(const void *ip, const struct xt_entry_target *target,
-                           int numeric)
-{
-       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
-
-       __REDIRECT_print(&range);
-}
-
-static void REDIRECT_save(const void *ip, const struct xt_entry_target *target)
-{
-       struct nf_nat_range2 range = RANGE2_INIT_FROM_IPV4_MRC(target->data);
-
-       __REDIRECT_save(&range);
-}
-
-static int REDIRECT_xlate(struct xt_xlate *xl,
-                          const struct xt_xlate_tg_params *params)
-{
-       struct nf_nat_range2 range =
-               RANGE2_INIT_FROM_IPV4_MRC(params->target->data);
-
-       return __NAT_xlate(xl, &range, AF_INET, "redirect");
-}
-
-static void REDIRECT_print6(const void *ip, const struct xt_entry_target *target,
-                            int numeric)
-{
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range));
-       __REDIRECT_print(&range);
-}
-
-static void REDIRECT_save6(const void *ip, const struct xt_entry_target *target)
-{
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, (const void *)target->data, sizeof(struct nf_nat_range));
-       __REDIRECT_save(&range);
-}
-
-static int REDIRECT_xlate6(struct xt_xlate *xl,
-                          const struct xt_xlate_tg_params *params)
-{
-       struct nf_nat_range2 range = {};
-
-       memcpy(&range, (const void *)params->target->data,
-              sizeof(struct nf_nat_range));
-       return __NAT_xlate(xl, &range, AF_INET6, "redirect");
-}
+PSX_GEN(REDIRECT6, RANGE2_INIT_FROM_RANGE, \
+       AF_INET6, "redir ports ", "--to-ports ", true, "redirect")
 
 static struct xtables_target dnat_tg_reg[] = {
        {
@@ -558,12 +464,12 @@ static struct xtables_target dnat_tg_reg[] = {
                .size           = XT_ALIGN(sizeof(struct nf_nat_range)),
                .userspacesize  = XT_ALIGN(sizeof(struct nf_nat_range)),
                .help           = DNAT_help,
-               .print          = DNAT_print6,
-               .save           = DNAT_save6,
+               .print          = DNAT6_print,
+               .save           = DNAT6_save,
                .x6_parse       = DNAT_parse6,
                .x6_fcheck      = DNAT_fcheck6,
                .x6_options     = DNAT_opts,
-               .xlate          = DNAT_xlate6,
+               .xlate          = DNAT6_xlate,
        },
        {
                .name           = "REDIRECT",
@@ -572,12 +478,12 @@ static struct xtables_target dnat_tg_reg[] = {
                .size           = XT_ALIGN(sizeof(struct nf_nat_range)),
                .userspacesize  = XT_ALIGN(sizeof(struct nf_nat_range)),
                .help           = REDIRECT_help,
-               .print          = REDIRECT_print6,
-               .save           = REDIRECT_save6,
+               .print          = REDIRECT6_print,
+               .save           = REDIRECT6_save,
                .x6_parse       = DNAT_parse6,
                .x6_fcheck      = DNAT_fcheck6,
                .x6_options     = REDIRECT_opts,
-               .xlate          = REDIRECT_xlate6,
+               .xlate          = REDIRECT6_xlate,
        },
        {
                .name           = "DNAT",
@@ -587,11 +493,11 @@ static struct xtables_target dnat_tg_reg[] = {
                .size           = XT_ALIGN(sizeof(struct nf_nat_range2)),
                .userspacesize  = XT_ALIGN(sizeof(struct nf_nat_range2)),
                .help           = DNAT_help_v2,
-               .print          = DNAT_print_v2,
-               .save           = DNAT_save_v2,
+               .print          = DNATv2_print,
+               .save           = DNATv2_save,
                .x6_parse       = DNAT_parse_v2,
                .x6_options     = DNAT_opts,
-               .xlate          = DNAT_xlate_v2,
+               .xlate          = DNATv2_xlate,
        },
        {
                .name           = "DNAT",
@@ -601,11 +507,11 @@ static struct xtables_target dnat_tg_reg[] = {
                .size           = XT_ALIGN(sizeof(struct nf_nat_range2)),
                .userspacesize  = XT_ALIGN(sizeof(struct nf_nat_range2)),
                .help           = DNAT_help_v2,
-               .print          = DNAT_print6_v2,
-               .save           = DNAT_save6_v2,
+               .print          = DNAT6v2_print,
+               .save           = DNAT6v2_save,
                .x6_parse       = DNAT_parse6_v2,
                .x6_options     = DNAT_opts,
-               .xlate          = DNAT_xlate6_v2,
+               .xlate          = DNAT6v2_xlate,
        },
 };