Refactoring original code so functions fits with xtables_target
structure.
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@xxxxxxxxxxxxxxx>
---
extensions/libxt_mangle.c | 389 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 389 insertions(+)
create mode 100644 extensions/libxt_mangle.c
diff --git a/extensions/libxt_mangle.c b/extensions/libxt_mangle.c
new file mode 100644
index 0000000..822033c
--- /dev/null
+++ b/extensions/libxt_mangle.c
@@ -0,0 +1,389 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Authors:
+ * Libarptc code from: Bart De Schuymer <bdschuym@xxxxxxxxxx>
+ * Port to libxtables: Tomasz Bursztyka <tomasz.bursztyka@xxxxxxxxxxxxxxx>
+ */
+
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <getopt.h>
+#include <errno.h>
+#include <netinet/ether.h>
+
+#include <xtables.h>
+#include <linux/netfilter_arp/arpt_mangle.h>
+
+static void mangle_help(void)
+{
+ printf(
+"mangle target options:\n"
+"--mangle-ip-s IP address\n"
+"--mangle-ip-d IP address\n"
+"--mangle-mac-s MAC address\n"
+"--mangle-mac-d MAC address\n"
+"--mangle-target target (DROP, CONTINUE or ACCEPT -- default is ACCEPT)\n"
+ );
+}
+
+#define MANGLE_IPS '1'
+#define MANGLE_IPT '2'
+#define MANGLE_DEVS '3'
+#define MANGLE_DEVT '4'
+#define MANGLE_TARGET '5'
+static const struct xt_option_entry mangle_opts[] = {
+ { .name = "mangle-ip-s", .id = MANGLE_IPS, .type = XTTYPE_STRING,
+ .flags = XTOPT_MAND },
+ { .name = "mangle-ip-d", .id = MANGLE_IPT, .type = XTTYPE_STRING,
+ .flags = XTOPT_MAND },
+ { .name = "mangle-mac-s", .id = MANGLE_DEVS, .type = XTTYPE_STRING,
+ .flags = XTOPT_MAND },
+ { .name = "mangle-mac-d", .id = MANGLE_DEVT, .type = XTTYPE_STRING,
+ .flags = XTOPT_MAND },
+ { .name = "mangle-target", .id = MANGLE_TARGET, .type = XTTYPE_STRING,
+ .flags = XTOPT_MAND },
+ XTOPT_TABLEEND,
+};
+
+
+static struct in_addr *network_to_addr(const char *name)
+{
+ struct netent *net;
+ static struct in_addr addr;
+
+ if ((net = getnetbyname(name)) != NULL) {
+ if (net->n_addrtype != AF_INET)
+ return (struct in_addr *) NULL;
+ addr.s_addr = htonl((unsigned long) net->n_net);
+ return &addr;
+ }
+
+ return (struct in_addr *) NULL;
+}
+
+static void inaddrcpy(struct in_addr *dst, struct in_addr *src)
+{
+ dst->s_addr = src->s_addr;
+}
+
+static struct in_addr *host_to_addr(const char *name, unsigned int *naddr)
+{
+ struct hostent *host;
+ struct in_addr *addr;
+ unsigned int i;
+
+ *naddr = 0;
+ if ((host = gethostbyname(name)) != NULL) {
+ if (host->h_addrtype != AF_INET ||
+ host->h_length != sizeof(struct in_addr))
+ return (struct in_addr *) NULL;
+
+ while (host->h_addr_list[*naddr] != (char *) NULL)
+ (*naddr)++;
+ addr = xtables_calloc(*naddr, sizeof(struct in_addr));
+ for (i = 0; i < *naddr; i++)
+ inaddrcpy(&(addr[i]),
+ (struct in_addr *) host->h_addr_list[i]);
+ return addr;
+ }
+
+ return (struct in_addr *) NULL;
+}
+
+static int string_to_number(const char *s, unsigned int min,
+ unsigned int max, unsigned int *ret)
+{
+ long number;
+ char *end;
+
+ /* Handle hex, octal, etc. */
+ errno = 0;
+ number = strtol(s, &end, 0);
+ if (*end == '\0' && end != s) {
+ /* we parsed a number, let's see if we want this */
+ if (errno != ERANGE && min <= number && number <= max) {
+ *ret = number;
+ return 0;
+ }
+ }
+ return -1;
+}
+
+static struct in_addr *dotted_to_addr(const char *dotted)
+{
+ static struct in_addr addr;
+ unsigned char *addrp;
+ char *p, *q;
+ unsigned int onebyte;
+ int i;
+ char buf[20];
+
+ /* copy dotted string, because we need to modify it */
+ strncpy(buf, dotted, sizeof(buf) - 1);
+ addrp = (unsigned char *) &(addr.s_addr);
+
+ p = buf;
+ for (i = 0; i < 3; i++) {
+ if ((q = strchr(p, '.')) == NULL)
+ return (struct in_addr *) NULL;
+
+ *q = '\0';
+ if (string_to_number(p, 0, 255, &onebyte) == -1)
+ return (struct in_addr *) NULL;
+
+ addrp[i] = (unsigned char) onebyte;
+ p = q + 1;
+ }
+
+ /* we've checked 3 bytes, now we check the last one */
+ if (string_to_number(p, 0, 255, &onebyte) == -1)
+ return (struct in_addr *) NULL;
+
+ addrp[3] = (unsigned char) onebyte;
+
+ return &addr;
+}
+
+static struct in_addr *parse_hostnetwork(const char *name,
+ unsigned int *naddrs)
+{
+ struct in_addr *addrp, *addrptmp;
+
+ if ((addrptmp = dotted_to_addr(name)) != NULL ||
+ (addrptmp = network_to_addr(name)) != NULL) {
+ addrp = xtables_malloc(sizeof(struct in_addr));
+ inaddrcpy(addrp, addrptmp);
+ *naddrs = 1;
+ return addrp;
+ }
+ if ((addrp = host_to_addr(name, naddrs)) != NULL)
+ return addrp;
+
+ xtables_error(PARAMETER_PROBLEM, "host/network `%s' not found", name);
+}
+
+static void mangle_parse(struct xt_option_call *cb)
+{
+ const struct arpt_entry *e = cb->xt_entry;
+ struct arpt_mangle *mangle = cb->data;
+ struct in_addr *ipaddr;
+ struct ether_addr *macaddr;
+
+ /* mangle target is by default "ACCEPT". Setting it here,
+ * since original arpt_mangle.c init() no longer exists*/
+ mangle->target = NF_ACCEPT;
+
+ xtables_option_parse(cb);
+ switch (cb->entry->id) {
+ case MANGLE_IPS:
+/*
+ if (e->arp.arpln_mask == 0)
+ xtables_error(PARAMETER_PROBLEM, "no pln defined");
+
+ if (e->arp.invflags & ARPT_INV_ARPPLN)
+ xtables_error(PARAMETER_PROBLEM,
+ "! pln not allowed for --mangle-ip-s");
+*/
+/*
+ if (e->arp.arpln != 4)
+ xtables_error(PARAMETER_PROBLEM, "only pln=4 supported");
+*/
+ {
+ unsigned int nr;
+ ipaddr = parse_hostnetwork(cb->arg, &nr);
+ }
+ mangle->u_s.src_ip.s_addr = ipaddr->s_addr;
+ free(ipaddr);
+ mangle->flags |= ARPT_MANGLE_SIP;
+ break;
+ case MANGLE_IPT:
+/*
+ if (e->arp.arpln_mask == 0)
+ xtables_error(PARAMETER_PROBLEM, "no pln defined");
+
+ if (e->arp.invflags & ARPT_INV_ARPPLN)
+ xtables_error(PARAMETER_PROBLEM,
+ "! pln not allowed for --mangle-ip-d");
+*/
+/*
+ if (e->arp.arpln != 4)
+ xtables_error(PARAMETER_PROBLEM, "only pln=4 supported");
+*/
+ {
+ unsigned int nr;
+ ipaddr = parse_hostnetwork(cb->arg, &nr);
+ }
+ mangle->u_t.tgt_ip.s_addr = ipaddr->s_addr;
+ free(ipaddr);
+ mangle->flags |= ARPT_MANGLE_TIP;
+ break;
+ case MANGLE_DEVS:
+ if (e->arp.arhln_mask == 0)
+ xtables_error(PARAMETER_PROBLEM,
+ "no --h-length defined");
+ if (e->arp.invflags & ARPT_INV_ARPHLN)
+ xtables_error(PARAMETER_PROBLEM,
+ "! --h-length not allowed for "
+ "--mangle-mac-s");
+ if (e->arp.arhln != 6)
+ xtables_error(PARAMETER_PROBLEM,
+ "only --h-length 6 supported");
+ macaddr = ether_aton(cb->arg);
+ if (macaddr == NULL)
+ xtables_error(PARAMETER_PROBLEM, "invalid source MAC");
+ memcpy(mangle->src_devaddr, macaddr, e->arp.arhln);
+ mangle->flags |= ARPT_MANGLE_SDEV;
+ break;
+ case MANGLE_DEVT:
+ if (e->arp.arhln_mask == 0)
+ xtables_error(PARAMETER_PROBLEM,
+ "no --h-length defined");
+ if (e->arp.invflags & ARPT_INV_ARPHLN)
+ xtables_error(PARAMETER_PROBLEM,
+ "! hln not allowed for --mangle-mac-d");
+ if (e->arp.arhln != 6)
+ xtables_error(PARAMETER_PROBLEM,
+ "only --h-length 6 supported");
+ macaddr = ether_aton(cb->arg);
+ if (macaddr == NULL)
+ xtables_error(PARAMETER_PROBLEM, "invalid target MAC");
+ memcpy(mangle->tgt_devaddr, macaddr, e->arp.arhln);
+ mangle->flags |= ARPT_MANGLE_TDEV;
+ break;
+ case MANGLE_TARGET:
+ if (!strcmp(cb->arg, "DROP"))
+ mangle->target = NF_DROP;
+ else if (!strcmp(cb->arg, "ACCEPT"))
+ mangle->target = NF_ACCEPT;
+ else if (!strcmp(cb->arg, "CONTINUE"))
+ mangle->target = ARPT_CONTINUE;
+ else
+ xtables_error(PARAMETER_PROBLEM,
+ "bad target for --mangle-target");
+ break;
+ }
+}
+
+static void mangle_fcheck(struct xt_fcheck_call *cb)
+{
+}
+
+static char *addr_to_dotted(const struct in_addr *addrp)
+{
+ static char buf[20];
+ const unsigned char *bytep;
+
+ bytep = (const unsigned char *) &(addrp->s_addr);
+ sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
+ return buf;
+}
+
+static char *addr_to_host(const struct in_addr *addr)
+{
+ struct hostent *host;
+
+ if ((host = gethostbyaddr((char *) addr,
+ sizeof(struct in_addr), AF_INET)) != NULL)
+ return (char *) host->h_name;
+
+ return (char *) NULL;
+}
+
+static char *addr_to_network(const struct in_addr *addr)
+{
+ struct netent *net;
+
+ if ((net = getnetbyaddr((long) ntohl(addr->s_addr), AF_INET)) != NULL)
+ return (char *) net->n_name;
+
+ return (char *) NULL;
+}
+
+static char *addr_to_anyname(const struct in_addr *addr)
+{
+ char *name;
+
+ if ((name = addr_to_host(addr)) != NULL ||
+ (name = addr_to_network(addr)) != NULL)
+ return name;
+
+ return addr_to_dotted(addr);
+}
+
+static void print_mac(const unsigned char *mac, int l)
+{
+ int j;
+
+ for (j = 0; j < l; j++)
+ printf("%02x%s", mac[j],
+ (j==l-1) ? "" : ":");
+}
+
+static void mangle_print(const void *ip, const struct xt_entry_target *target,
+ int numeric)
+{
+ const struct arpt_mangle *m = (const void *)target;
+ char buf[100];
+
+ if (m->flags & ARPT_MANGLE_SIP) {
+ if (numeric)
+ sprintf(buf, "%s", addr_to_dotted(&(m->u_s.src_ip)));
+ else
+ sprintf(buf, "%s", addr_to_anyname(&(m->u_s.src_ip)));
+ printf("--mangle-ip-s %s ", buf);
+ }
+ if (m->flags & ARPT_MANGLE_SDEV) {
+ printf("--mangle-mac-s ");
+ print_mac((unsigned char *)m->src_devaddr, 6);
+ printf(" ");
+ }
+ if (m->flags & ARPT_MANGLE_TIP) {
+ if (numeric)
+ sprintf(buf, "%s", addr_to_dotted(&(m->u_t.tgt_ip)));
+ else
+ sprintf(buf, "%s", addr_to_anyname(&(m->u_t.tgt_ip)));
+ printf("--mangle-ip-d %s ", buf);
+ }
+ if (m->flags & ARPT_MANGLE_TDEV) {
+ printf("--mangle-mac-d ");
+ print_mac((unsigned char *)m->tgt_devaddr, 6);
+ printf(" ");
+ }
+ if (m->target != NF_ACCEPT) {
+ printf("--mangle-target ");
+ if (m->target == NF_DROP)
+ printf("DROP ");
+ else
+ printf("CONTINUE ");
+ }
+}
+
+static void mangle_save(const void *ip, const struct xt_entry_target *target)
+{
+}
+
+static struct xtables_target mangle_tg_reg = {
+ .family = NFPROTO_ARP,
+ .name = "mangle",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct arpt_mangle)),
+ .userspacesize = XT_ALIGN(sizeof(struct arpt_mangle)),
+ .help = mangle_help,
+ .x6_parse = mangle_parse,
+ .x6_fcheck = mangle_fcheck,
+ .print = mangle_print,
+ .save = mangle_save,
+ .x6_options = mangle_opts,
+};
+
+void _init(void)
+{
+ xtables_register_target(&mangle_tg_reg);
+}
--
1.8.3.2
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