diff options
Diffstat (limited to 'examples/nft-rule-add.c')
-rw-r--r-- | examples/nft-rule-add.c | 257 |
1 files changed, 147 insertions, 110 deletions
diff --git a/examples/nft-rule-add.c b/examples/nft-rule-add.c index f896bc0..0534fa5 100644 --- a/examples/nft-rule-add.c +++ b/examples/nft-rule-add.c @@ -14,126 +14,178 @@ #include <string.h> #include <stddef.h> /* for offsetof */ #include <netinet/in.h> +#include <netinet/ip.h> +#include <netinet/tcp.h> #include <arpa/inet.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <errno.h> #include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> #include <linux/netfilter/nf_tables.h> #include <libmnl/libmnl.h> #include <libnftables/rule.h> #include <libnftables/expr.h> -#include <linux/netfilter_ipv4/ipt_LOG.h> -#include <linux/netfilter/xt_iprange.h> - -#include <netinet/ip.h> - -static void add_target_log(struct nft_rule_expr *e) +static void add_payload(struct nft_rule *r, uint32_t base, uint32_t dreg, + uint32_t offset, uint32_t len) { - struct ipt_log_info *info; + struct nft_rule_expr *e; - nft_rule_expr_set(e, NFT_EXPR_TG_NAME, "LOG", strlen("LOG")); - nft_rule_expr_set_u32(e, NFT_EXPR_TG_REV, 0); - - info = calloc(1, sizeof(struct ipt_log_info)); - if (info == NULL) - return; + e = nft_rule_expr_alloc("payload"); + if (e == NULL) { + perror("expr payload oom"); + exit(EXIT_FAILURE); + } - sprintf(info->prefix, "test: "); - info->prefix[sizeof(info->prefix)-1] = '\0'; - info->logflags = 0x0f; - info->level = 5; + nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_BASE, base); + nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_DREG, dreg); + nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_OFFSET, offset); + nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_LEN, len); - nft_rule_expr_set(e, NFT_EXPR_TG_INFO, info, sizeof(*info)); + nft_rule_add_expr(r, e); } -static void add_expr_target(struct nft_rule *r) +static void add_cmp(struct nft_rule *r, uint32_t sreg, uint32_t op, + const void *data, uint32_t data_len) { - struct nft_rule_expr *expr; + struct nft_rule_expr *e; - expr = nft_rule_expr_alloc("target"); - if (expr == NULL) - return; + e = nft_rule_expr_alloc("cmp"); + if (e == NULL) { + perror("expr cmp oom"); + exit(EXIT_FAILURE); + } - add_target_log(expr); + nft_rule_expr_set_u32(e, NFT_EXPR_CMP_SREG, sreg); + nft_rule_expr_set_u32(e, NFT_EXPR_CMP_OP, op); + nft_rule_expr_set(e, NFT_EXPR_CMP_DATA, data, data_len); - nft_rule_add_expr(r, expr); + nft_rule_add_expr(r, e); } -static void add_match_iprange(struct nft_rule_expr *e) +static void add_counter(struct nft_rule *r) { - struct xt_iprange_mtinfo *info; - - nft_rule_expr_set(e, NFT_EXPR_MT_NAME, "iprange", strlen("iprange")); - nft_rule_expr_set_u32(e, NFT_EXPR_MT_REV, 1); + struct nft_rule_expr *e; - info = calloc(1, sizeof(struct xt_iprange_mtinfo)); - if (info == NULL) - return; - - info->src_min.ip = info->dst_min.ip = inet_addr("127.0.0.1"); - info->src_max.ip = info->dst_max.ip = inet_addr("127.0.0.1"); - info->flags = IPRANGE_SRC; + e = nft_rule_expr_alloc("counter"); + if (e == NULL) { + perror("expr counter oom"); + exit(EXIT_FAILURE); + } - nft_rule_expr_set(e, NFT_EXPR_MT_INFO, info, sizeof(*info)); + nft_rule_add_expr(r, e); } -static void add_expr_match(struct nft_rule *r) +static struct nft_rule *setup_rule(uint8_t family, const char *table, + const char *chain) { - struct nft_rule_expr *expr; + struct nft_rule *r = NULL; + uint8_t proto; + uint16_t dport; - expr = nft_rule_expr_alloc("match"); - if (expr == NULL) - return; + r = nft_rule_alloc(); + if (r == NULL) { + perror("OOM"); + exit(EXIT_FAILURE); + } - add_match_iprange(expr); + nft_rule_attr_set(r, NFT_RULE_ATTR_TABLE, table); + nft_rule_attr_set(r, NFT_RULE_ATTR_CHAIN, chain); + nft_rule_attr_set_u32(r, NFT_RULE_ATTR_FAMILY, family); - nft_rule_add_expr(r, expr); -} + 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)); -#define field_sizeof(t, f) (sizeof(((t *)NULL)->f)) + 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)); -static void add_payload2(struct nft_rule_expr *e) -{ - nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_BASE, - NFT_PAYLOAD_NETWORK_HEADER); - nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_DREG, NFT_REG_1); - nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_OFFSET, - offsetof(struct iphdr, protocol)); - nft_rule_expr_set_u32(e, NFT_EXPR_PAYLOAD_LEN, 1); + add_counter(r); + + return r; } -static void add_payload(struct nft_rule *r) +static int seq; + +static void nft_mnl_batch_put(struct mnl_nlmsg_batch *batch, int type) { - struct nft_rule_expr *expr; + struct nlmsghdr *nlh; + struct nfgenmsg *nfg; - expr = nft_rule_expr_alloc("payload"); - if (expr == NULL) - return; + nlh = mnl_nlmsg_put_header(mnl_nlmsg_batch_current(batch)); + nlh->nlmsg_type = type; + nlh->nlmsg_flags = NLM_F_REQUEST; + nlh->nlmsg_seq = seq++; - add_payload2(expr); + nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg)); + nfg->nfgen_family = AF_INET; + nfg->version = NFNETLINK_V0; + nfg->res_id = NFNL_SUBSYS_NFTABLES; - nft_rule_add_expr(r, expr); + mnl_nlmsg_batch_next(batch); +} + +static int nft_mnl_batch_talk(struct mnl_socket *nl, struct mnl_nlmsg_batch *b) +{ + int ret, fd = mnl_socket_get_fd(nl); + char rcv_buf[MNL_SOCKET_BUFFER_SIZE]; + fd_set readfds; + struct timeval tv = { + .tv_sec = 0, + .tv_usec = 0 + }; + + ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(b), + mnl_nlmsg_batch_size(b)); + if (ret == -1) + goto err; + + FD_ZERO(&readfds); + FD_SET(fd, &readfds); + + /* receive and digest all the acknowledgments from the kernel. */ + ret = select(fd+1, &readfds, NULL, NULL, &tv); + if (ret == -1) + goto err; + + while (ret > 0 && FD_ISSET(fd, &readfds)) { + ret = mnl_socket_recvfrom(nl, rcv_buf, sizeof(rcv_buf)); + if (ret == -1) + goto err; + + ret = mnl_cb_run(rcv_buf, ret, 0, mnl_socket_get_portid(nl), + NULL, NULL); + if (ret < 0) + goto err; + + ret = select(fd+1, &readfds, NULL, NULL, &tv); + if (ret == -1) + goto err; + + FD_ZERO(&readfds); + FD_SET(fd, &readfds); + } +err: + return ret; } int main(int argc, char *argv[]) { struct mnl_socket *nl; - char buf[MNL_SOCKET_BUFFER_SIZE]; + struct nft_rule *r; struct nlmsghdr *nlh; - uint32_t portid, seq; - struct nft_rule *r = NULL; - int ret, family; + struct mnl_nlmsg_batch *batch; + uint8_t family; + char buf[4096]; if (argc != 4) { - fprintf(stderr, "Usage: %s <family> <table> <chain>\n", - argv[0]); - exit(EXIT_FAILURE); - } - - r = nft_rule_alloc(); - if (r == NULL) { - perror("OOM"); + fprintf(stderr, "Usage: %s <family> <table> <chain>\n", argv[0]); exit(EXIT_FAILURE); } @@ -141,32 +193,12 @@ int main(int argc, char *argv[]) family = NFPROTO_IPV4; else if (strcmp(argv[1], "ip6") == 0) family = NFPROTO_IPV6; - else if (strcmp(argv[1], "bridge") == 0) - family = NFPROTO_BRIDGE; - else if (strcmp(argv[1], "arp") == 0) - family = NFPROTO_ARP; else { - fprintf(stderr, "Unknown family: ip, ip6, bridge, arp\n"); + fprintf(stderr, "Unknown family: ip, ip6\n"); exit(EXIT_FAILURE); } - nft_rule_attr_set(r, NFT_RULE_ATTR_TABLE, argv[2]); - nft_rule_attr_set(r, NFT_RULE_ATTR_CHAIN, argv[3]); - - add_expr_match(r); - add_payload(r); - add_expr_target(r); - - char tmp[1024]; - nft_rule_snprintf(tmp, sizeof(tmp), r, 0, 0); - printf("%s\n", tmp); - - seq = time(NULL); - nlh = nft_rule_nlmsg_build_hdr(buf, NFT_MSG_NEWRULE, family, - NLM_F_APPEND|NLM_F_ACK|NLM_F_CREATE, - seq); - nft_rule_nlmsg_build_payload(nlh, r); - nft_rule_free(r); + r = setup_rule(family, argv[2], argv[3]); nl = mnl_socket_open(NETLINK_NETFILTER); if (nl == NULL) { @@ -178,24 +210,29 @@ int main(int argc, char *argv[]) perror("mnl_socket_bind"); exit(EXIT_FAILURE); } - portid = mnl_socket_get_portid(nl); - if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { - perror("mnl_socket_send"); - exit(EXIT_FAILURE); - } + batch = mnl_nlmsg_batch_start(buf, sizeof(buf)); - ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); - while (ret > 0) { - ret = mnl_cb_run(buf, ret, seq, portid, NULL, NULL); - if (ret <= 0) - break; - ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); - } - if (ret == -1) { - perror("error"); + nft_mnl_batch_put(batch, NFNL_MSG_BATCH_BEGIN); + + nlh = nft_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch), + NFT_MSG_NEWRULE, + nft_rule_attr_get_u32(r, NFT_RULE_ATTR_FAMILY), + NLM_F_APPEND|NLM_F_CREATE, seq); + + nft_rule_nlmsg_build_payload(nlh, r); + nft_rule_free(r); + mnl_nlmsg_batch_next(batch); + + nft_mnl_batch_put(batch, NFNL_MSG_BATCH_END); + + if (nft_mnl_batch_talk(nl, batch) < 0) { + perror("Netlink problem"); exit(EXIT_FAILURE); } + + mnl_nlmsg_batch_stop(batch); + mnl_socket_close(nl); return EXIT_SUCCESS; |