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Diffstat (limited to 'examples/netfilter/nfct-create-batch.c')
| -rw-r--r-- | examples/netfilter/nfct-create-batch.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/examples/netfilter/nfct-create-batch.c b/examples/netfilter/nfct-create-batch.c new file mode 100644 index 0000000..36ad8c7 --- /dev/null +++ b/examples/netfilter/nfct-create-batch.c @@ -0,0 +1,192 @@ +/* + * (C) 2010 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * This software may be used and distributed according to the terms + * of the GNU General Public License, incorporated herein by reference. + */ +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <arpa/inet.h> +#include <time.h> +#include <sys/select.h> +#include <string.h> + +#include <libmnl/libmnl.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nfnetlink_conntrack.h> +#include <linux/netfilter/nf_conntrack_common.h> +#include <linux/netfilter/nf_conntrack_tcp.h> + +static void put_msg(char *buf, uint16_t i, int seq) +{ + struct nlmsghdr *nlh; + struct nfgenmsg *nfh; + struct nlattr *nest1, *nest2; + + nlh = mnl_nlmsg_put_header(buf); + nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW; + nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_EXCL|NLM_F_ACK; + nlh->nlmsg_seq = seq; + + nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg)); + nfh->nfgen_family = AF_INET; + nfh->version = NFNETLINK_V0; + nfh->res_id = 0; + + nest1 = mnl_attr_nest_start(nlh, CTA_TUPLE_ORIG); + nest2 = mnl_attr_nest_start(nlh, CTA_TUPLE_IP); + mnl_attr_put_u32(nlh, CTA_IP_V4_SRC, inet_addr("1.1.1.1")); + mnl_attr_put_u32(nlh, CTA_IP_V4_DST, inet_addr("2.2.2.2")); + mnl_attr_nest_end(nlh, nest2); + + nest2 = mnl_attr_nest_start(nlh, CTA_TUPLE_PROTO); + mnl_attr_put_u8(nlh, CTA_PROTO_NUM, IPPROTO_TCP); + mnl_attr_put_u16(nlh, CTA_PROTO_SRC_PORT, htons(i)); + mnl_attr_put_u16(nlh, CTA_PROTO_DST_PORT, htons(1025)); + mnl_attr_nest_end(nlh, nest2); + mnl_attr_nest_end(nlh, nest1); + + nest1 = mnl_attr_nest_start(nlh, CTA_TUPLE_REPLY); + nest2 = mnl_attr_nest_start(nlh, CTA_TUPLE_IP); + mnl_attr_put_u32(nlh, CTA_IP_V4_SRC, inet_addr("2.2.2.2")); + mnl_attr_put_u32(nlh, CTA_IP_V4_DST, inet_addr("1.1.1.1")); + mnl_attr_nest_end(nlh, nest2); + + nest2 = mnl_attr_nest_start(nlh, CTA_TUPLE_PROTO); + mnl_attr_put_u8(nlh, CTA_PROTO_NUM, IPPROTO_TCP); + mnl_attr_put_u16(nlh, CTA_PROTO_SRC_PORT, htons(1025)); + mnl_attr_put_u16(nlh, CTA_PROTO_DST_PORT, htons(i)); + mnl_attr_nest_end(nlh, nest2); + mnl_attr_nest_end(nlh, nest1); + + nest1 = mnl_attr_nest_start(nlh, CTA_PROTOINFO); + nest2 = mnl_attr_nest_start(nlh, CTA_PROTOINFO_TCP); + mnl_attr_put_u8(nlh, CTA_PROTOINFO_TCP_STATE, TCP_CONNTRACK_SYN_SENT); + mnl_attr_nest_end(nlh, nest2); + mnl_attr_nest_end(nlh, nest1); + + mnl_attr_put_u32(nlh, CTA_STATUS, htonl(IPS_CONFIRMED)); + mnl_attr_put_u32(nlh, CTA_TIMEOUT, htonl(1000)); +} + +static int cb_err(const struct nlmsghdr *nlh, void *data) +{ + struct nlmsgerr *err = (void *)(nlh + 1); + if (err->error != 0) + printf("message with seq %u has failed: %s\n", + nlh->nlmsg_seq, strerror(-err->error)); + return MNL_CB_OK; +} + +static mnl_cb_t cb_ctl_array[NLMSG_MIN_TYPE] = { + [NLMSG_ERROR] = cb_err, +}; + +static void +send_batch(struct mnl_socket *nl, struct mnl_nlmsg_batch *b, int portid) +{ + int ret, fd = mnl_socket_get_fd(nl); + size_t len = mnl_nlmsg_batch_size(b); + char rcv_buf[MNL_SOCKET_BUFFER_SIZE]; + + ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(b), len); + if (ret == -1) { + perror("mnl_socket_recvfrom"); + exit(EXIT_FAILURE); + } + + /* receive and digest all the acknowledgments from the kernel. */ + struct timeval tv = { + .tv_sec = 0, + .tv_usec = 0 + }; + fd_set readfds; + FD_ZERO(&readfds); + FD_SET(fd, &readfds); + + ret = select(fd+1, &readfds, NULL, NULL, &tv); + if (ret == -1) { + perror("select"); + exit(EXIT_FAILURE); + } + while (ret > 0 && FD_ISSET(fd, &readfds)) { + ret = mnl_socket_recvfrom(nl, rcv_buf, sizeof(rcv_buf)); + if (ret == -1) { + perror("mnl_socket_recvfrom"); + exit(EXIT_FAILURE); + } + + ret = mnl_cb_run2(rcv_buf, ret, 0, portid, + NULL, NULL, cb_ctl_array, + MNL_ARRAY_SIZE(cb_ctl_array)); + if (ret == -1) { + perror("mnl_cb_run"); + exit(EXIT_FAILURE); + } + + ret = select(fd+1, &readfds, NULL, NULL, &tv); + if (ret == -1) { + perror("select"); + exit(EXIT_FAILURE); + } + FD_ZERO(&readfds); + FD_SET(fd, &readfds); + } +} + +int main(void) +{ + struct mnl_socket *nl; + char snd_buf[MNL_SOCKET_BUFFER_SIZE*2]; + struct mnl_nlmsg_batch *b; + int j; + unsigned int seq, portid; + uint16_t i; + + nl = mnl_socket_open(NETLINK_NETFILTER); + if (nl == NULL) { + perror("mnl_socket_open"); + exit(EXIT_FAILURE); + } + if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) { + perror("mnl_socket_bind"); + exit(EXIT_FAILURE); + } + portid = mnl_socket_get_portid(nl); + + /* The buffer that we use to batch messages is MNL_SOCKET_BUFFER_SIZE + * multiplied by 2 bytes long, but we limit the batch to half of it + * since the last message that does not fit the batch goes over the + * upper boundary, if you break this rule, expect memory corruptions. */ + b = mnl_nlmsg_batch_start(snd_buf, MNL_SOCKET_BUFFER_SIZE); + if (b == NULL) { + perror("mnl_nlmsg_batch_start"); + exit(EXIT_FAILURE); + } + + seq = time(NULL); + for (i=1024, j=0; i<65535; i++, j++) { + put_msg(mnl_nlmsg_batch_current(b), i, seq+j); + + /* is there room for more messages in this batch? + * if so, continue. */ + if (mnl_nlmsg_batch_next(b)) + continue; + + send_batch(nl, b, portid); + + /* this moves the last message that did not fit into the + * batch to the head of it. */ + mnl_nlmsg_batch_reset(b); + } + + /* check if there is any message in the batch not sent yet. */ + if (!mnl_nlmsg_batch_is_empty(b)) + send_batch(nl, b, portid); + + mnl_nlmsg_batch_stop(b); + mnl_socket_close(nl); + + return 0; +} |