unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

[NETFILTER] ctnetlink: allow userspace to change TCP state

Browse source 
This patch adds the ability of changing the state a TCP connection. I know
that this must be used with care but it's required to provide a complete
conntrack creation via conntrack_netlink. So I'll document this aspect on
the upcoming docs.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pablo Neira Ayuso 2005-10-10 21:23:28 -07:00 committed by David S. Miller
parent a051a8f730
commit 3392315375
2 changed files with 26 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
include/linux/netfilter_ipv4/ip_conntrack_protocol.h
View file

@ -52,6 +52,9 @@ struct ip_conntrack_protocol
int (*to_nfattr)(struct sk_buff *skb, struct nfattr *nfa,
const struct ip_conntrack *ct);
/* convert nfnetlink attributes to protoinfo */
int (*from_nfattr)(struct nfattr *tb[], struct ip_conntrack *ct);
int (*tuple_to_nfattr)(struct sk_buff *skb,
const struct ip_conntrack_tuple *t);
int (*nfattr_to_tuple)(struct nfattr *tb[],

23
net/ipv4/netfilter/ip_conntrack_proto_tcp.c
View file

@ -356,6 +356,28 @@ static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
read_unlock_bh(&tcp_lock);
return -1;
}
static int nfattr_to_tcp(struct nfattr *cda[], struct ip_conntrack *ct)
{
struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
if (nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr) < 0)
goto nfattr_failure;
if (!tb[CTA_PROTOINFO_TCP_STATE-1])
return -EINVAL;
write_lock_bh(&tcp_lock);
ct->proto.tcp.state =
*(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
write_unlock_bh(&tcp_lock);
return 0;
nfattr_failure:
return -1;
}
#endif
static unsigned int get_conntrack_index(const struct tcphdr *tcph)
@ -1127,6 +1149,7 @@ struct ip_conntrack_protocol ip_conntrack_protocol_tcp =
#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
.to_nfattr = tcp_to_nfattr,
.from_nfattr = nfattr_to_tcp,
.tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
.nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
#endif