static int build_rule_snat(int index, const char *address,
struct nftnl_rule **res)
{
struct nftnl_rule *rule;
struct nftnl_expr *expr;
uint32_t snat;
int err;
/*
* # nft --debug netlink add rule connman nat-postrouting \
* oif eth0 snat 1.2.3.4
* ip connman nat-postrouting
* [ meta load oif => reg 1 ]
* [ cmp eq reg 1 0x0000000b ]
* [ immediate reg 1 0x04030201 ]
* [ nat snat ip addr_min reg 1 addr_max reg 0 ]
*/
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);
/* OIF */
expr = nftnl_expr_alloc("meta");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, NFT_META_OIF);
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, &index, sizeof(index));
if (err < 0)
goto err;
/* snat */
expr = nftnl_expr_alloc("immediate");
if (!expr)
goto err;
snat = inet_addr(address);
nftnl_expr_set_u32(expr, NFTNL_EXPR_IMM_DREG, NFT_REG_1);
nftnl_expr_set(expr, NFTNL_EXPR_IMM_DATA, &snat, sizeof(snat));
nftnl_rule_add_expr(rule, expr);
expr = nftnl_expr_alloc("nat");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_NAT_TYPE, NFT_NAT_SNAT);
nftnl_expr_set_u32(expr, NFTNL_EXPR_NAT_FAMILY, NFPROTO_IPV4);
nftnl_expr_set_u32(expr, NFTNL_EXPR_NAT_REG_ADDR_MIN, NFT_REG_1);
nftnl_rule_add_expr(rule, expr);
*res = rule;
return 0;
err:
nftnl_rule_free(rule);
return -ENOMEM;
}
static int build_rule_src_ip(const char *src_ip, uint32_t mark, struct nftnl_rule **res)
{
struct nftnl_rule *rule;
struct nftnl_expr *expr;
int err;
in_addr_t s_addr;
/*
* # nft --debug netlink add rule connman route-output \
* ip saddr 192.168.10.31 mark set 1234
*
* ip connman route-output
* [ payload load 4b @ network header + 12 => reg 1 ]
* [ cmp eq reg 1 0x1f0aa8c0 ]
* [ immediate reg 1 0x000004d2 ]
* [ meta set mark with reg 1 ]
*/
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_ROUTE_OUTPUT);
/* family ipv4 */
nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, NFPROTO_IPV4);
/* source IP */
err = add_payload(rule, NFT_PAYLOAD_NETWORK_HEADER, NFT_REG_1,
offsetof(struct iphdr, saddr), sizeof(struct in_addr));
if (err < 0)
goto err;
s_addr = inet_addr(src_ip);
err = add_cmp(rule, NFT_REG_1, NFT_CMP_EQ, &s_addr, sizeof(s_addr));
if (err < 0)
goto err;
expr = nftnl_expr_alloc("immediate");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_IMM_DREG, NFT_REG_1);
nftnl_expr_set(expr, NFTNL_EXPR_IMM_DATA, &mark, sizeof(mark));
nftnl_rule_add_expr(rule, expr);
expr = nftnl_expr_alloc("meta");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, NFT_META_MARK);
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_SREG, NFT_REG_1);
nftnl_rule_add_expr(rule, expr);
*res = rule;
return 0;
err:
return -ENOMEM;
}
static int build_rule_marking(uid_t uid, uint32_t mark, struct nftnl_rule **res)
{
struct nftnl_rule *rule;
struct nftnl_expr *expr;
int err;
/*
* http://wiki.nftables.org/wiki-nftables/index.php/Setting_packet_metainformation
* http://wiki.nftables.org/wiki-nftables/index.php/Matching_packet_metainformation
*
* # nft --debug netlink add rule connman route-output \
* meta skuid wagi mark set 1234
*
* ip connman route-output
* [ meta load skuid => reg 1 ]
* [ cmp eq reg 1 0x000003e8 ]
* [ immediate reg 1 0x000004d2 ]
* [ meta set mark with reg 1 ]
*/
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_ROUTE_OUTPUT);
expr = nftnl_expr_alloc("meta");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, NFT_META_SKUID);
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, &uid, sizeof(uid));
if (err < 0)
goto err;
expr = nftnl_expr_alloc("immediate");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_IMM_DREG, NFT_REG_1);
nftnl_expr_set(expr, NFTNL_EXPR_IMM_DATA, &mark, sizeof(mark));
nftnl_rule_add_expr(rule, expr);
expr = nftnl_expr_alloc("meta");
if (!expr)
goto err;
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, NFT_META_MARK);
nftnl_expr_set_u32(expr, NFTNL_EXPR_META_SREG, NFT_REG_1);
nftnl_rule_add_expr(rule, expr);
*res = rule;
return 0;
err:
return -ENOMEM;
}
static struct nftnl_rule *setup_rule(uint8_t family, const char *table,
const char *chain, const char *handle)
{
struct nftnl_rule *r = NULL;
uint8_t proto;
uint16_t dport;
uint64_t handle_num;
r = nftnl_rule_alloc();
if (r == NULL) {
perror("OOM");
exit(EXIT_FAILURE);
}
nftnl_rule_set(r, NFTNL_RULE_TABLE, table);
nftnl_rule_set(r, NFTNL_RULE_CHAIN, chain);
nftnl_rule_set_u32(r, NFTNL_RULE_FAMILY, family);
if (handle != NULL) {
handle_num = atoll(handle);
nftnl_rule_set_u64(r, NFTNL_RULE_POSITION, handle_num);
}
proto = IPPROTO_TCP;
add_payload(r, NFT_PAYLOAD_NETWORK_HEADER, NFT_REG_1,
offsetof(struct iphdr, protocol), sizeof(uint8_t));
add_cmp(r, NFT_REG_1, NFT_CMP_EQ, &proto, sizeof(uint8_t));
dport = htons(22);
add_payload(r, NFT_PAYLOAD_TRANSPORT_HEADER, NFT_REG_1,
offsetof(struct tcphdr, dest), sizeof(uint16_t));
add_cmp(r, NFT_REG_1, NFT_CMP_EQ, &dport, sizeof(uint16_t));
add_counter(r);
return r;
}
char* opcode(unsigned char* arg0) {
switch (arg0[0])
{
case 0x33:
return "xor";
case 0x83:
return add_cmp(&arg0[1]);
case 0x85:
return "test";
case 0x89:
return "mov";
case 0x8b:
return "mov";
default:
return "unknown";
}
}
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;
}