Ejemplo n.º 1
0
void add_addr(struct nftnl_rule *r, int offset,
	      void *data, void *mask, size_t len, uint32_t op)
{
	add_payload(r, offset, len, NFT_PAYLOAD_NETWORK_HEADER);
	add_bitwise(r, mask, len);

	add_cmp_ptr(r, op, data, len);
}
Ejemplo n.º 2
0
static int build_rule_nat(const char *address, unsigned char prefixlen,
				const char *interface, struct nftnl_rule **res)
{
	struct nftnl_rule *rule;
	struct in_addr ipv4_addr, ipv4_mask;
	struct nftnl_expr *expr;
	int err;

	/*
	 * # nft --debug netlink add rule connman nat-postrouting	\
	 *	oifname eth0 ip saddr 10.10.0.0/24 masquerade
	 *
	 *	ip connman nat-postrouting
	 *	  [ meta load oifname => reg 1 ]
	 *	  [ cmp eq reg 1 0x30687465 0x00000000 0x00000000 0x00000000 ]
	 *	  [ payload load 4b @ network header + 12 => reg 1 ]
	 *	  [ bitwise reg 1 = (reg=1 & 0x00ffffff ) ^ 0x00000000 ]
	 *	  [ cmp eq reg 1 0x00000a0a ]
	 *	  [ masq ]
	 */

	rule = nftnl_rule_alloc();
	if (!rule)
		return -ENOMEM;

	nftnl_rule_set(rule, NFTNL_RULE_TABLE, CONNMAN_TABLE);
	nftnl_rule_set(rule, NFTNL_RULE_CHAIN, CONNMAN_CHAIN_NAT_POST);

	/* family ipv4 */
	nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, NFPROTO_IPV4);

	/* oifname */
	expr = nftnl_expr_alloc("meta");
	if (!expr)
		goto err;
	nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, NFT_META_OIFNAME);
	nftnl_expr_set_u32(expr, NFTNL_EXPR_META_DREG, NFT_REG_1);
	nftnl_rule_add_expr(rule, expr);
	err = add_cmp(rule, NFT_REG_1, NFT_CMP_EQ, interface,
			strlen(interface) + 1);
	if (err < 0)
		goto err;

	/* source */
	ipv4_mask.s_addr = htonl((0xffffffff << (32 - prefixlen)) & 0xffffffff);
	ipv4_addr.s_addr = inet_addr(address);
	ipv4_addr.s_addr &= ipv4_mask.s_addr;

	err = add_payload(rule, NFT_PAYLOAD_NETWORK_HEADER, NFT_REG_1,
			offsetof(struct iphdr, saddr), sizeof(struct in_addr));
	if (err < 0)
		goto err;
	err = add_bitwise(rule, NFT_REG_1, &ipv4_mask.s_addr,
				sizeof(struct in_addr));
	if (err < 0)
		goto err;
	err = add_cmp(rule, NFT_REG_1, NFT_CMP_EQ, &ipv4_addr.s_addr,
			sizeof(struct in_addr));
	if (err < 0)
		goto err;

	/* masquerade */
        expr = nftnl_expr_alloc("masq");
        if (!expr)
		goto err;
        nftnl_rule_add_expr(rule, expr);

	*res = rule;
	return 0;

err:
	nftnl_rule_free(rule);
	return -ENOMEM;
}