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netutils/netlib: Add netfilter conntrack functions

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Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
This commit is contained in:
Zhe Weng 2024-03-25 16:36:30 +08:00 committed by Xiang Xiao
parent 000a8bcdf1
commit 7e7b108ef9
4 changed files with 424 additions and 0 deletions
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64
include/netutils/netlib.h
View File

@ -123,6 +123,60 @@ struct netlib_device_s
};
#endif /* CONFIG_NETLINK_ROUTE*/
#ifdef CONFIG_NETLINK_NETFILTER
/* Describes one connection returned by netlib_get_conntrack() */
union netlib_conntrack_addr_u
{
#ifdef CONFIG_NET_IPv4
struct in_addr ipv4;
#endif
#ifdef CONFIG_NET_IPv6
struct in6_addr ipv6;
#endif
};
struct netlib_conntrack_tuple_s
{
union netlib_conntrack_addr_u src;
union netlib_conntrack_addr_u dst;
union
{
struct
{
uint16_t sport;
uint16_t dport;
} tcp; /* and udp */
struct
{
uint16_t id;
uint8_t type;
uint8_t code;
} icmp; /* and icmp6 */
} l4;
uint8_t l4proto;
};
struct netlib_conntrack_s
{
struct netlib_conntrack_tuple_s orig;
struct netlib_conntrack_tuple_s reply;
sa_family_t family; /* AF_INET or AF_INET6 */
uint8_t type; /* IPCTNL_MSG_CT_* */
};
/* There might be many conntrack entries, so we don't use array of data, but
* use callback instead.
*/
typedef CODE int (*netlib_conntrack_cb_t)(FAR struct netlib_conntrack_s *ct);
#endif /* CONFIG_NETLINK_NETFILTER */
#ifdef CONFIG_NETUTILS_NETLIB_GENERICURLPARSER
struct url_s
{
@ -355,6 +409,16 @@ FAR struct ipt_entry *netlib_ipt_masquerade_entry(FAR const char *ifname);
# endif
#endif
#ifdef CONFIG_NETLINK_NETFILTER
/* Netfilter connection tracking support */
struct nlmsghdr; /* Forward reference */
int netlib_parse_conntrack(FAR const struct nlmsghdr *nlh, size_t len,
FAR struct netlib_conntrack_s *ct);
int netlib_get_conntrack(sa_family_t family, netlib_conntrack_cb_t cb);
#endif
/* HTTP support */
int netlib_parsehttpurl(FAR const char *url, uint16_t *port,

6
netutils/netlib/CMakeLists.txt
View File

@ -84,6 +84,12 @@ if(CONFIG_NETUTILS_NETLIB)
endif()
endif()
# Netfilter connection support
if(CONFIG_NETLINK_NETFILTER)
list(APPEND SRCS netlib_conntrack.c)
endif()
# These require TCP support
if(CONFIG_NET_TCP)

6
netutils/netlib/Makefile
View File

@ -85,6 +85,12 @@ CSRCS += netlib_getroute.c
endif
endif
# Netfilter connection support
ifeq ($(CONFIG_NETLINK_NETFILTER),y)
CSRCS += netlib_conntrack.c
endif
# These require TCP support
ifeq ($(CONFIG_NET_TCP),y)

348
netutils/netlib/netlib_conntrack.c Normal file
View File

@ -0,0 +1,348 @@
/****************************************************************************
* apps/netutils/netlib/netlib_conntrack.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <netpacket/netlink.h>
#include <nuttx/net/ip.h>
#include "netutils/netlib.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define RXBUFFER_SIZE 256
/****************************************************************************
* Private Types
****************************************************************************/
struct netlib_conntrack_sendto_request_s
{
struct nlmsghdr hdr;
struct nfgenmsg msg;
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: netlib_ct_parse_ip
****************************************************************************/
static void netlib_ct_parse_ip(FAR const struct nfattr *attr,
FAR struct netlib_conntrack_tuple_s *tuple)
{
FAR const struct nfattr *subattr = NFA_DATA(attr);
ssize_t paylen = NFA_PAYLOAD(attr);
for (; NFA_OK(subattr, paylen); subattr = NFA_NEXT(subattr, paylen))
{
switch (NFA_TYPE(subattr))
{
case CTA_IP_V4_SRC:
net_ipv4addr_hdrcopy(&tuple->src.ipv4, NFA_DATA(subattr));
break;
case CTA_IP_V4_DST:
net_ipv4addr_hdrcopy(&tuple->dst.ipv4, NFA_DATA(subattr));
break;
case CTA_IP_V6_SRC:
net_ipv6addr_hdrcopy(&tuple->src.ipv6, NFA_DATA(subattr));
break;
case CTA_IP_V6_DST:
net_ipv6addr_hdrcopy(&tuple->dst.ipv6, NFA_DATA(subattr));
break;
}
}
}
/****************************************************************************
* Name: netlib_ct_parse_proto
****************************************************************************/
static void netlib_ct_parse_proto(FAR const struct nfattr *attr,
FAR struct netlib_conntrack_tuple_s *tuple)
{
FAR const struct nfattr *subattr = NFA_DATA(attr);
ssize_t paylen = NFA_PAYLOAD(attr);
for (; NFA_OK(subattr, paylen); subattr = NFA_NEXT(subattr, paylen))
{
switch (NFA_TYPE(subattr))
{
case CTA_PROTO_NUM:
tuple->l4proto = *(FAR uint8_t *)NFA_DATA(subattr);
break;
case CTA_PROTO_SRC_PORT:
tuple->l4.tcp.sport = ntohs(*(FAR uint16_t *)NFA_DATA(subattr));
break;
case CTA_PROTO_DST_PORT:
tuple->l4.tcp.dport = ntohs(*(FAR uint16_t *)NFA_DATA(subattr));
break;
case CTA_PROTO_ICMP_ID:
case CTA_PROTO_ICMPV6_ID:
tuple->l4.icmp.id = ntohs(*(FAR uint16_t *)NFA_DATA(subattr));
break;
case CTA_PROTO_ICMP_TYPE:
case CTA_PROTO_ICMPV6_TYPE:
tuple->l4.icmp.type = *(FAR uint8_t *)NFA_DATA(subattr);
break;
case CTA_PROTO_ICMP_CODE:
case CTA_PROTO_ICMPV6_CODE:
tuple->l4.icmp.code = *(FAR uint8_t *)NFA_DATA(subattr);
break;
}
}
}
/****************************************************************************
* Name: netlib_ct_parse_tuple
****************************************************************************/
static void netlib_ct_parse_tuple(FAR const struct nfattr *attr,
FAR struct netlib_conntrack_tuple_s *tuple)
{
FAR const struct nfattr *subattr = NFA_DATA(attr);
ssize_t paylen = NFA_PAYLOAD(attr);
for (; NFA_OK(subattr, paylen); subattr = NFA_NEXT(subattr, paylen))
{
switch (NFA_TYPE(subattr))
{
case CTA_TUPLE_IP:
netlib_ct_parse_ip(subattr, tuple);
break;
case CTA_TUPLE_PROTO:
netlib_ct_parse_proto(subattr, tuple);
break;
}
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: netlib_parse_conntrack
*
* Description:
* Parse a conntrack message.
*
* Input Parameters:
* nlh - The netlink message to parse.
* ct - The conntrack to fill.
*
* Returned Value:
* OK on success, -errno on failure.
*
****************************************************************************/
int netlib_parse_conntrack(FAR const struct nlmsghdr *nlh, size_t len,
FAR struct netlib_conntrack_s *ct)
{
FAR const struct nfgenmsg *nfmsg;
FAR const struct nfattr *attr;
ssize_t paylen;
if (len < sizeof(struct nlmsghdr) || len < nlh->nlmsg_len)
{
fprintf(stderr, "Error message length got %zd vs %" PRIu32 "\n",
len, nlh->nlmsg_len);
return -EINVAL;
}
if (NFNL_SUBSYS_ID(nlh->nlmsg_type) != NFNL_SUBSYS_CTNETLINK)
{
fprintf(stderr, "Unknown message type %" PRIx32 "\n", nlh->nlmsg_type);
return -ENOTSUP;
}
nfmsg = NLMSG_DATA(nlh);
attr = NFM_NFA(nfmsg);
paylen = NFM_PAYLOAD(nlh);
ct->family = nfmsg->nfgen_family;
ct->type = NFNL_MSG_TYPE(nlh->nlmsg_type);
for (; NFA_OK(attr, paylen); attr = NFA_NEXT(attr, paylen))
{
switch (NFA_TYPE(attr))
{
case CTA_TUPLE_ORIG:
netlib_ct_parse_tuple(attr, &ct->orig);
break;
case CTA_TUPLE_REPLY:
netlib_ct_parse_tuple(attr, &ct->reply);
break;
}
}
return OK;
}
/****************************************************************************
* Name: netlib_get_conntrack
*
* Description:
* Get the conntrack table.
*
* Input Parameters:
* family - The address family to get the conntrack table for.
* cb - The callback to call for each conntrack entry.
*
* Returned Value:
* The number of conntrack entries processed on success, -errno on failure.
*
****************************************************************************/
int netlib_get_conntrack(sa_family_t family, netlib_conntrack_cb_t cb)
{
FAR const struct nlmsghdr *nlh;
struct netlib_conntrack_sendto_request_s req;
struct netlib_conntrack_s ct;
struct sockaddr_nl addr;
static unsigned int seqno = 0;
unsigned int thiseq;
uint8_t buf[RXBUFFER_SIZE];
ssize_t nrecvd;
size_t cnt;
int fd;
int ret;
/* Create a NetLink socket with NETLINK_NETFILTER protocol */
fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_NETFILTER);
if (fd < 0)
{
perror("ERROR: failed to create netlink socket");
return -errno;
}
addr.nl_family = AF_NETLINK;
addr.nl_pad = 0;
addr.nl_pid = getpid();
addr.nl_groups = 0;
if (bind(fd, (FAR const struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("ERROR: failed to bind netlink socket");
ret = -errno;
goto errout_with_socket;
}
/* Initialize the request */
thiseq = ++seqno;
memset(&req, 0, sizeof(req));
req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct nfgenmsg));
req.hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
req.hdr.nlmsg_seq = thiseq;
req.hdr.nlmsg_type = NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_CT_GET;
req.hdr.nlmsg_pid = addr.nl_pid;
req.msg.nfgen_family = family;
req.msg.version = NFNETLINK_V0;
req.msg.res_id = 0;
ret = send(fd, &req, req.hdr.nlmsg_len, 0);
if (ret < 0)
{
perror("ERROR: send() failed");
ret = -errno;
goto errout_with_socket;
}
/* Read the response */
for (cnt = 0; ; cnt++)
{
nrecvd = recv(fd, buf, sizeof(buf), 0);
if (nrecvd < 0)
{
perror("ERROR: recv() failed");
ret = -errno;
goto errout_with_socket;
}
nlh = (FAR struct nlmsghdr *)buf;
/* Verify the data and transfer the connection info to the caller */
if (nrecvd < sizeof(struct nlmsghdr) ||
nlh->nlmsg_len < sizeof(struct nlmsghdr))
{
fprintf(stderr, "ERROR: Bad message\n");
ret = -EIO;
goto errout_with_socket;
}
/* The sequence number in the response should match the sequence
* number in the request (since we created the socket, this should
* always be true).
*/
if (nlh->nlmsg_seq != thiseq)
{
fprintf(stderr, "ERROR: Bad sequence number in response\n");
ret = -EIO;
goto errout_with_socket;
}
/* Callback the connection info to the caller */
if (nlh->nlmsg_type == NLMSG_DONE)
{
ret = cnt;
break;
}
ret = netlib_parse_conntrack(nlh, nrecvd, &ct);
if (ret < 0)
{
fprintf(stderr, "ERROR: failed to parse conntrack message\n");
goto errout_with_socket;
}
ret = cb(&ct);
if (ret < 0)
{
fprintf(stderr, "ERROR: callback failed\n");
goto errout_with_socket;
}
}
errout_with_socket:
close(fd);
return ret;
}