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yaml
---
r: 215497
b: refs/heads/master
c: cc6eb43
h: refs/heads/master
i:
  215495: a186245
v: v3
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Balazs Scheidler authored and Patrick McHardy committed Oct 21, 2010
1 parent 196eb32 commit ab135df
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Showing 2 changed files with 133 additions and 71 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: b64c9256a9b76fc9f059f71bd08ba88fb0cbba2e
refs/heads/master: cc6eb433856983e91071469c4ce57accb6947ccb
202 changes: 132 additions & 70 deletions trunk/net/netfilter/xt_TPROXY.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,15 +16,41 @@
#include <net/checksum.h>
#include <net/udp.h>
#include <net/inet_sock.h>

#include <linux/inetdevice.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/xt_TPROXY.h>

#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
#include <net/if_inet6.h>
#include <net/addrconf.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif

#include <net/netfilter/nf_tproxy_core.h>
#include <linux/netfilter/xt_TPROXY.h>

static inline __be32
tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
{
struct in_device *indev;
__be32 laddr;

if (user_laddr)
return user_laddr;

laddr = 0;
rcu_read_lock();
indev = __in_dev_get_rcu(skb->dev);
for_primary_ifa(indev) {
laddr = ifa->ifa_local;
break;
} endfor_ifa(indev);
rcu_read_unlock();

return laddr ? laddr : daddr;
}

/**
* tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
Expand Down Expand Up @@ -75,60 +101,6 @@ tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
return sk;
}

/**
* tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.
* @tproto: Transport protocol.
* @thoff: Transport protocol header offset.
* @par: Iptables target parameters.
* @sk: The TIME_WAIT TCP socket found by the lookup.
*
* We have to handle SYN packets arriving to TIME_WAIT sockets
* differently: instead of reopening the connection we should rather
* redirect the new connection to the proxy if there's a listener
* socket present.
*
* tproxy_handle_time_wait6() consumes the socket reference passed in.
*
* Returns the listener socket if there's one, the TIME_WAIT socket if
* no such listener is found, or NULL if the TCP header is incomplete.
*/
static struct sock *
tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
const struct xt_action_param *par,
struct sock *sk)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct tcphdr _hdr, *hp;
const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;

hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
if (hp == NULL) {
inet_twsk_put(inet_twsk(sk));
return NULL;
}

if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
/* SYN to a TIME_WAIT socket, we'd rather redirect it
* to a listener socket if there's one */
struct sock *sk2;

sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
&iph->saddr,
!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
hp->source,
tgi->lport ? tgi->lport : hp->dest,
skb->dev, NFT_LOOKUP_LISTENER);
if (sk2) {
inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
inet_twsk_put(inet_twsk(sk));
sk = sk2;
}
}

return sk;
}

static unsigned int
tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
u_int32_t mark_mask, u_int32_t mark_value)
Expand All @@ -150,6 +122,10 @@ tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
hp->source, hp->dest,
skb->dev, NFT_LOOKUP_ESTABLISHED);

laddr = tproxy_laddr4(skb, laddr, iph->daddr);
if (!lport)
lport = hp->dest;

/* UDP has no TCP_TIME_WAIT state, so we never enter here */
if (sk && sk->sk_state == TCP_TIME_WAIT)
/* reopening a TIME_WAIT connection needs special handling */
Expand All @@ -158,8 +134,8 @@ tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
/* no, there's no established connection, check if
* there's a listener on the redirected addr/port */
sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), iph->protocol,
iph->saddr, laddr ? laddr : iph->daddr,
hp->source, lport ? lport : hp->dest,
iph->saddr, laddr,
hp->source, lport,
skb->dev, NFT_LOOKUP_LISTENER);

/* NOTE: assign_sock consumes our sk reference */
Expand All @@ -174,9 +150,9 @@ tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
return NF_ACCEPT;
}

pr_debug("no socket, dropping: proto %hhu %08x:%hu -> %08x:%hu, mark: %x\n",
iph->protocol, ntohl(iph->daddr), ntohs(hp->dest),
ntohl(laddr), ntohs(lport), skb->mark);
pr_debug("no socket, dropping: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
iph->protocol, &iph->saddr, ntohs(hp->source),
&iph->daddr, ntohs(hp->dest), skb->mark);
return NF_DROP;
}

Expand All @@ -197,13 +173,97 @@ tproxy_tg4_v1(struct sk_buff *skb, const struct xt_action_param *par)
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

static inline const struct in6_addr *
tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
const struct in6_addr *daddr)
{
struct inet6_dev *indev;
struct inet6_ifaddr *ifa;
struct in6_addr *laddr;

if (!ipv6_addr_any(user_laddr))
return user_laddr;
laddr = NULL;

rcu_read_lock();
indev = __in6_dev_get(skb->dev);
if (indev)
list_for_each_entry(ifa, &indev->addr_list, if_list) {
if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED))
continue;

laddr = &ifa->addr;
break;
}
rcu_read_unlock();

return laddr ? laddr : daddr;
}

/**
* tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.
* @tproto: Transport protocol.
* @thoff: Transport protocol header offset.
* @par: Iptables target parameters.
* @sk: The TIME_WAIT TCP socket found by the lookup.
*
* We have to handle SYN packets arriving to TIME_WAIT sockets
* differently: instead of reopening the connection we should rather
* redirect the new connection to the proxy if there's a listener
* socket present.
*
* tproxy_handle_time_wait6() consumes the socket reference passed in.
*
* Returns the listener socket if there's one, the TIME_WAIT socket if
* no such listener is found, or NULL if the TCP header is incomplete.
*/
static struct sock *
tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
const struct xt_action_param *par,
struct sock *sk)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct tcphdr _hdr, *hp;
const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;

hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr);
if (hp == NULL) {
inet_twsk_put(inet_twsk(sk));
return NULL;
}

if (hp->syn && !hp->rst && !hp->ack && !hp->fin) {
/* SYN to a TIME_WAIT socket, we'd rather redirect it
* to a listener socket if there's one */
struct sock *sk2;

sk2 = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
&iph->saddr,
tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr),
hp->source,
tgi->lport ? tgi->lport : hp->dest,
skb->dev, NFT_LOOKUP_LISTENER);
if (sk2) {
inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
inet_twsk_put(inet_twsk(sk));
sk = sk2;
}
}

return sk;
}

static unsigned int
tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
const struct xt_tproxy_target_info_v1 *tgi = par->targinfo;
struct udphdr _hdr, *hp;
struct sock *sk;
const struct in6_addr *laddr;
__be16 lport;
int thoff;
int tproto;

Expand All @@ -228,6 +288,9 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
hp->source, hp->dest,
par->in, NFT_LOOKUP_ESTABLISHED);

laddr = tproxy_laddr6(skb, &tgi->laddr.in6, &iph->daddr);
lport = tgi->lport ? tgi->lport : hp->dest;

/* UDP has no TCP_TIME_WAIT state, so we never enter here */
if (sk && sk->sk_state == TCP_TIME_WAIT)
/* reopening a TIME_WAIT connection needs special handling */
Expand All @@ -236,10 +299,8 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
/* no there's no established connection, check if
* there's a listener on the redirected addr/port */
sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
&iph->saddr,
!ipv6_addr_any(&tgi->laddr.in6) ? &tgi->laddr.in6 : &iph->daddr,
hp->source,
tgi->lport ? tgi->lport : hp->dest,
&iph->saddr, laddr,
hp->source, lport,
par->in, NFT_LOOKUP_LISTENER);

/* NOTE: assign_sock consumes our sk reference */
Expand All @@ -249,14 +310,15 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;

pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
tproto, &iph->saddr, ntohs(hp->dest),
&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
tproto, &iph->saddr, ntohs(hp->source),
laddr, ntohs(lport), skb->mark);
return NF_ACCEPT;
}

pr_debug("no socket, dropping: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
tproto, &iph->saddr, ntohs(hp->dest),
&tgi->laddr.in6, ntohs(tgi->lport), skb->mark);
tproto, &iph->saddr, ntohs(hp->source),
&iph->daddr, ntohs(hp->dest), skb->mark);

return NF_DROP;
}

Expand Down

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