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-rw-r--r--libipq/libipq.c380
1 files changed, 380 insertions, 0 deletions
diff --git a/libipq/libipq.c b/libipq/libipq.c
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+++ b/libipq/libipq.c
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+/*
+ * libipq.c
+ *
+ * IPQ userspace library.
+ *
+ * Please note that this library is still developmental, and there may
+ * be some API changes.
+ *
+ * Author: James Morris <jmorris@intercode.com.au>
+ *
+ * 07-11-2001 Modified by Fernando Anton to add support for IPv6.
+ *
+ * Copyright (c) 2000-2001 Netfilter Core Team
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+#include <libipq/libipq.h>
+#include <netinet/in.h>
+#include <linux/netfilter.h>
+
+/****************************************************************************
+ *
+ * Private interface
+ *
+ ****************************************************************************/
+
+enum {
+ IPQ_ERR_NONE = 0,
+ IPQ_ERR_IMPL,
+ IPQ_ERR_HANDLE,
+ IPQ_ERR_SOCKET,
+ IPQ_ERR_BIND,
+ IPQ_ERR_BUFFER,
+ IPQ_ERR_RECV,
+ IPQ_ERR_NLEOF,
+ IPQ_ERR_ADDRLEN,
+ IPQ_ERR_STRUNC,
+ IPQ_ERR_RTRUNC,
+ IPQ_ERR_NLRECV,
+ IPQ_ERR_SEND,
+ IPQ_ERR_SUPP,
+ IPQ_ERR_RECVBUF,
+ IPQ_ERR_TIMEOUT,
+ IPQ_ERR_PROTOCOL
+};
+#define IPQ_MAXERR IPQ_ERR_PROTOCOL
+
+struct ipq_errmap_t {
+ int errcode;
+ char *message;
+} ipq_errmap[] = {
+ { IPQ_ERR_NONE, "Unknown error" },
+ { IPQ_ERR_IMPL, "Implementation error" },
+ { IPQ_ERR_HANDLE, "Unable to create netlink handle" },
+ { IPQ_ERR_SOCKET, "Unable to create netlink socket" },
+ { IPQ_ERR_BIND, "Unable to bind netlink socket" },
+ { IPQ_ERR_BUFFER, "Unable to allocate buffer" },
+ { IPQ_ERR_RECV, "Failed to receive netlink message" },
+ { IPQ_ERR_NLEOF, "Received EOF on netlink socket" },
+ { IPQ_ERR_ADDRLEN, "Invalid peer address length" },
+ { IPQ_ERR_STRUNC, "Sent message truncated" },
+ { IPQ_ERR_RTRUNC, "Received message truncated" },
+ { IPQ_ERR_NLRECV, "Received error from netlink" },
+ { IPQ_ERR_SEND, "Failed to send netlink message" },
+ { IPQ_ERR_SUPP, "Operation not supported" },
+ { IPQ_ERR_RECVBUF, "Receive buffer size invalid" },
+ { IPQ_ERR_TIMEOUT, "Timeout"},
+ { IPQ_ERR_PROTOCOL, "Invalid protocol specified" }
+};
+
+static int ipq_errno = IPQ_ERR_NONE;
+
+static ssize_t ipq_netlink_sendto(const struct ipq_handle *h,
+ const void *msg, size_t len);
+
+static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h,
+ unsigned char *buf, size_t len,
+ int timeout);
+
+static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h,
+ const struct msghdr *msg,
+ unsigned int flags);
+
+static char *ipq_strerror(int errcode);
+
+static ssize_t ipq_netlink_sendto(const struct ipq_handle *h,
+ const void *msg, size_t len)
+{
+ int status = sendto(h->fd, msg, len, 0,
+ (struct sockaddr *)&h->peer, sizeof(h->peer));
+ if (status < 0)
+ ipq_errno = IPQ_ERR_SEND;
+ return status;
+}
+
+static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h,
+ const struct msghdr *msg,
+ unsigned int flags)
+{
+ int status = sendmsg(h->fd, msg, flags);
+ if (status < 0)
+ ipq_errno = IPQ_ERR_SEND;
+ return status;
+}
+
+static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h,
+ unsigned char *buf, size_t len,
+ int timeout)
+{
+ unsigned int addrlen;
+ int status;
+ struct nlmsghdr *nlh;
+
+ if (len < sizeof(struct nlmsgerr)) {
+ ipq_errno = IPQ_ERR_RECVBUF;
+ return -1;
+ }
+ addrlen = sizeof(h->peer);
+
+ if (timeout != 0) {
+ int ret;
+ struct timeval tv;
+ fd_set read_fds;
+
+ if (timeout < 0) {
+ /* non-block non-timeout */
+ tv.tv_sec = 0;
+ tv.tv_usec = 0;
+ } else {
+ tv.tv_sec = timeout / 1000000;
+ tv.tv_usec = timeout % 1000000;
+ }
+
+ FD_ZERO(&read_fds);
+ FD_SET(h->fd, &read_fds);
+ ret = select(h->fd+1, &read_fds, NULL, NULL, &tv);
+ if (ret < 0) {
+ if (errno == EINTR) {
+ return 0;
+ } else {
+ ipq_errno = IPQ_ERR_RECV;
+ return -1;
+ }
+ }
+ if (!FD_ISSET(h->fd, &read_fds)) {
+ ipq_errno = IPQ_ERR_TIMEOUT;
+ return 0;
+ }
+ }
+ status = recvfrom(h->fd, buf, len, 0,
+ (struct sockaddr *)&h->peer, &addrlen);
+ if (status < 0) {
+ ipq_errno = IPQ_ERR_RECV;
+ return status;
+ }
+ if (addrlen != sizeof(h->peer)) {
+ ipq_errno = IPQ_ERR_RECV;
+ return -1;
+ }
+ if (h->peer.nl_pid != 0) {
+ ipq_errno = IPQ_ERR_RECV;
+ return -1;
+ }
+ if (status == 0) {
+ ipq_errno = IPQ_ERR_NLEOF;
+ return -1;
+ }
+ nlh = (struct nlmsghdr *)buf;
+ if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) {
+ ipq_errno = IPQ_ERR_RTRUNC;
+ return -1;
+ }
+ return status;
+}
+
+static char *ipq_strerror(int errcode)
+{
+ if (errcode < 0 || errcode > IPQ_MAXERR)
+ errcode = IPQ_ERR_IMPL;
+ return ipq_errmap[errcode].message;
+}
+
+/****************************************************************************
+ *
+ * Public interface
+ *
+ ****************************************************************************/
+
+/*
+ * Create and initialise an ipq handle.
+ */
+struct ipq_handle *ipq_create_handle(u_int32_t flags, u_int32_t protocol)
+{
+ int status;
+ struct ipq_handle *h;
+
+ h = (struct ipq_handle *)malloc(sizeof(struct ipq_handle));
+ if (h == NULL) {
+ ipq_errno = IPQ_ERR_HANDLE;
+ return NULL;
+ }
+
+ memset(h, 0, sizeof(struct ipq_handle));
+
+ if (protocol == NFPROTO_IPV4)
+ h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_FIREWALL);
+ else if (protocol == NFPROTO_IPV6)
+ h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IP6_FW);
+ else {
+ ipq_errno = IPQ_ERR_PROTOCOL;
+ free(h);
+ return NULL;
+ }
+
+ if (h->fd == -1) {
+ ipq_errno = IPQ_ERR_SOCKET;
+ close(h->fd);
+ free(h);
+ return NULL;
+ }
+ memset(&h->local, 0, sizeof(struct sockaddr_nl));
+ h->local.nl_family = AF_NETLINK;
+ h->local.nl_pid = getpid();
+ h->local.nl_groups = 0;
+ status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local));
+ if (status == -1) {
+ ipq_errno = IPQ_ERR_BIND;
+ close(h->fd);
+ free(h);
+ return NULL;
+ }
+ memset(&h->peer, 0, sizeof(struct sockaddr_nl));
+ h->peer.nl_family = AF_NETLINK;
+ h->peer.nl_pid = 0;
+ h->peer.nl_groups = 0;
+ return h;
+}
+
+/*
+ * No error condition is checked here at this stage, but it may happen
+ * if/when reliable messaging is implemented.
+ */
+int ipq_destroy_handle(struct ipq_handle *h)
+{
+ if (h) {
+ close(h->fd);
+ free(h);
+ }
+ return 0;
+}
+
+int ipq_set_mode(const struct ipq_handle *h,
+ u_int8_t mode, size_t range)
+{
+ struct {
+ struct nlmsghdr nlh;
+ ipq_peer_msg_t pm;
+ } req;
+
+ memset(&req, 0, sizeof(req));
+ req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
+ req.nlh.nlmsg_flags = NLM_F_REQUEST;
+ req.nlh.nlmsg_type = IPQM_MODE;
+ req.nlh.nlmsg_pid = h->local.nl_pid;
+ req.pm.msg.mode.value = mode;
+ req.pm.msg.mode.range = range;
+ return ipq_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
+}
+
+/*
+ * timeout is in microseconds (1 second is 1000000 (1 million) microseconds)
+ *
+ */
+ssize_t ipq_read(const struct ipq_handle *h,
+ unsigned char *buf, size_t len, int timeout)
+{
+ return ipq_netlink_recvfrom(h, buf, len, timeout);
+}
+
+int ipq_message_type(const unsigned char *buf)
+{
+ return ((struct nlmsghdr*)buf)->nlmsg_type;
+}
+
+int ipq_get_msgerr(const unsigned char *buf)
+{
+ struct nlmsghdr *h = (struct nlmsghdr *)buf;
+ struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
+ return -err->error;
+}
+
+ipq_packet_msg_t *ipq_get_packet(const unsigned char *buf)
+{
+ return NLMSG_DATA((struct nlmsghdr *)(buf));
+}
+
+int ipq_set_verdict(const struct ipq_handle *h,
+ ipq_id_t id,
+ unsigned int verdict,
+ size_t data_len,
+ unsigned char *buf)
+{
+ unsigned char nvecs;
+ size_t tlen;
+ struct nlmsghdr nlh;
+ ipq_peer_msg_t pm;
+ struct iovec iov[3];
+ struct msghdr msg;
+
+ memset(&nlh, 0, sizeof(nlh));
+ nlh.nlmsg_flags = NLM_F_REQUEST;
+ nlh.nlmsg_type = IPQM_VERDICT;
+ nlh.nlmsg_pid = h->local.nl_pid;
+ memset(&pm, 0, sizeof(pm));
+ pm.msg.verdict.value = verdict;
+ pm.msg.verdict.id = id;
+ pm.msg.verdict.data_len = data_len;
+ iov[0].iov_base = &nlh;
+ iov[0].iov_len = sizeof(nlh);
+ iov[1].iov_base = &pm;
+ iov[1].iov_len = sizeof(pm);
+ tlen = sizeof(nlh) + sizeof(pm);
+ nvecs = 2;
+ if (data_len && buf) {
+ iov[2].iov_base = buf;
+ iov[2].iov_len = data_len;
+ tlen += data_len;
+ nvecs++;
+ }
+ msg.msg_name = (void *)&h->peer;
+ msg.msg_namelen = sizeof(h->peer);
+ msg.msg_iov = iov;
+ msg.msg_iovlen = nvecs;
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_flags = 0;
+ nlh.nlmsg_len = tlen;
+ return ipq_netlink_sendmsg(h, &msg, 0);
+}
+
+/* Not implemented yet */
+int ipq_ctl(const struct ipq_handle *h, int request, ...)
+{
+ return 1;
+}
+
+char *ipq_errstr(void)
+{
+ return ipq_strerror(ipq_errno);
+}
+
+void ipq_perror(const char *s)
+{
+ if (s)
+ fputs(s, stderr);
+ else
+ fputs("ERROR", stderr);
+ if (ipq_errno)
+ fprintf(stderr, ": %s", ipq_errstr());
+ if (errno)
+ fprintf(stderr, ": %s", strerror(errno));
+ fputc('\n', stderr);
+}
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