/*
* em_ipset.c IPset Ematch
*
* (C) 2012 Florian Westphal <fw@strlen.de>
*
* Parts taken from iptables libxt_set.h:
* Copyright (C) 2000-2002 Joakim Axelsson <gozem@linux.nu>
* Patrick Schaaf <bof@bof.de>
* Martin Josefsson <gandalf@wlug.westbo.se>
* Copyright (C) 2003-2010 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <stdbool.h>
#include <stdio.h>
#include <errno.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <xtables.h>
#include <linux/netfilter/ipset/ip_set.h>
#ifndef IPSET_INVALID_ID
typedef __u16 ip_set_id_t;
enum ip_set_dim {
IPSET_DIM_ZERO = 0,
IPSET_DIM_ONE,
IPSET_DIM_TWO,
IPSET_DIM_THREE,
IPSET_DIM_MAX = 6,
};
#endif /* IPSET_INVALID_ID */
#include <linux/netfilter/xt_set.h>
#include "m_ematch.h"
#ifndef IPSET_INVALID_ID
#define IPSET_INVALID_ID 65535
#define SO_IP_SET 83
union ip_set_name_index {
char name[IPSET_MAXNAMELEN];
__u16 index;
};
#define IP_SET_OP_GET_BYNAME 0x00000006 /* Get set index by name */
struct ip_set_req_get_set {
unsigned op;
unsigned version;
union ip_set_name_index set;
};
#define IP_SET_OP_GET_BYINDEX 0x00000007 /* Get set name by index */
/* Uses ip_set_req_get_set */
#define IP_SET_OP_VERSION 0x00000100 /* Ask kernel version */
struct ip_set_req_version {
unsigned op;
unsigned version;
};
#endif /* IPSET_INVALID_ID */
extern struct ematch_util ipset_ematch_util;
static int get_version(unsigned *version)
{
int res, sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
struct ip_set_req_version req_version;
socklen_t size = sizeof(req_version);
if (sockfd < 0) {
fputs("Can't open socket to ipset.\n", stderr);
return -1;
}
req_version.op = IP_SET_OP_VERSION;
res = getsockopt(sockfd, SOL_IP, SO_IP_SET, &req_version, &size);
if (res != 0) {
perror("xt_set getsockopt");
return -1;
}
*version = req_version.version;
return sockfd;
}
static int do_getsockopt(struct ip_set_req_get_set *req)
{
int sockfd, res;
socklen_t size = sizeof(struct ip_set_req_get_set);
sockfd = get_version(&req->version);
if (sockfd < 0)
return -1;
res = getsockopt(sockfd, SOL_IP, SO_IP_SET, req, &size);
if (res != 0)
perror("Problem when communicating with ipset");
close(sockfd);
if (res != 0)
return -1;
if (size != sizeof(struct ip_set_req_get_set)) {
fprintf(stderr,
"Incorrect return size from kernel during ipset lookup, "
"(want %zu, got %zu)\n",
sizeof(struct ip_set_req_get_set), (size_t)size);
return -1;
}
return res;
}
static int
get_set_byid(char *setname, unsigned int idx)
{
struct ip_set_req_get_set req;
int res;
req.op = IP_SET_OP_GET_BYINDEX;
req.set.index = idx;
res = do_getsockopt(&req);
if (res != 0)
return -1;
if (req.set.name[0] == '\0') {
fprintf(stderr,
"Set with index %i in kernel doesn't exist.\n", idx);
return -1;
}
strncpy(setname, req.set.name, IPSET_MAXNAMELEN);
return 0;
}
static int
get_set_byname(const char *setname, struct xt_set_info *info)
{
struct ip_set_req_get_set req;
int res;
req.op = IP_SET_OP_GET_BYNAME;
strncpy(req.set.name, setname, IPSET_MAXNAMELEN);
req.set.name[IPSET_MAXNAMELEN - 1] = '\0';
res = do_getsockopt(&req);
if (res != 0)
return -1;
if (req.set.index == IPSET_INVALID_ID)
return -1;
info->index = req.set.index;
return 0;
}
static int
parse_dirs(const char *opt_arg, struct xt_set_info *info)
{
char *saved = strdup(opt_arg);
char *ptr, *tmp = saved;
if (!tmp) {
perror("strdup");
return -1;
}
while (info->dim < IPSET_DIM_MAX && tmp != NULL) {
info->dim++;
ptr = strsep(&tmp, ",");
if (strncmp(ptr, "src", 3) == 0)
info->flags |= (1 << info->dim);
else if (strncmp(ptr, "dst", 3) != 0) {
fputs("You must specify (the comma separated list of) 'src' or 'dst'\n", stderr);
free(saved);
return -1;
}
}
if (tmp)
fprintf(stderr, "Can't be more src/dst options than %u", IPSET_DIM_MAX);
free(saved);
return tmp ? -1 : 0;
}
static void ipset_print_usage(FILE *fd)
{
fprintf(fd,
"Usage: ipset(SETNAME FLAGS)\n" \
"where: SETNAME:= string\n" \
" FLAGS := { FLAG[,FLAGS] }\n" \
" FLAG := { src | dst }\n" \
"\n" \
"Example: 'ipset(bulk src,dst)'\n");
}
static int ipset_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
struct bstr *args)
{
struct xt_set_info set_info;
int ret;
memset(&set_info, 0, sizeof(set_info));
#define PARSE_ERR(CARG, FMT, ARGS...) \
em_parse_error(EINVAL, args, CARG, &ipset_ematch_util, FMT ,##ARGS)
if (args == NULL)
return PARSE_ERR(args, "ipset: missing set name");
if (args->len >= IPSET_MAXNAMELEN)
return PARSE_ERR(args, "ipset: set name too long (max %u)", IPSET_MAXNAMELEN - 1);
ret = get_set_byname(args->data, &set_info);
if (ret < 0)
return PARSE_ERR(args, "ipset: unknown set name '%s'", args->data);
if (args->next == NULL)
return PARSE_ERR(args, "ipset: missing set flags");
args = bstr_next(args);
if (parse_dirs(args->data, &set_info))
return PARSE_ERR(args, "ipset: error parsing set flags");
if (args->next) {
args = bstr_next(args);
return PARSE_ERR(args, "ipset: unknown parameter");
}
addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
addraw_l(n, MAX_MSG, &set_info, sizeof(set_info));
#undef PARSE_ERR
return 0;
}
static int ipset_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
int data_len)
{
int i;
char setname[IPSET_MAXNAMELEN];
const struct xt_set_info *set_info = data;
if (data_len != sizeof(*set_info)) {
fprintf(stderr, "xt_set_info struct size mismatch\n");
return -1;
}
if (get_set_byid(setname, set_info->index))
return -1;
fputs(setname, fd);
for (i = 1; i <= set_info->dim; i++) {
fprintf(fd, "%s%s", i == 1 ? " " : ",", set_info->flags & (1 << i) ? "src" : "dst");
}
return 0;
}
struct ematch_util ipset_ematch_util = {
.kind = "ipset",
.kind_num = TCF_EM_IPSET,
.parse_eopt = ipset_parse_eopt,
.print_eopt = ipset_print_eopt,
.print_usage = ipset_print_usage
};