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IPVS now supports fragmented packets, with support from nf_conntrack_reasm.c
Based on patch from: Hans Schillstrom.
IPVS do like conntrack i.e. use the skb->nfct_reasm
(i.e. when all fragments is collected, nf_ct_frag6_output()
starts a "re-play" of all fragments into the interrupted
PREROUTING chain at prio -399 (NF_IP6_PRI_CONNTRACK_DEFRAG+1)
with nfct_reasm pointing to the assembled packet.)
Notice, module nf_defrag_ipv6 must be loaded for this to work.
IPVS adds a new hook into prerouting chain at prio
-99 (NF_IP6_PRI_NAT_DST+1) to catch fragments, and copy fw-mark
info from the first packet with an upper layer header.
Also, for IPv6, handle all ICMPv6 NONE Informational Messages (via
ICMPV6_INFOMSG_MASK). This actually only extend our handling to
type ICMPV6_PARAMPROB (Parameter Problem), and future types.
- Fixed refcnt bug since last.
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Hans Schillstrom <hans@xxxxxxxxxxxxxxx>
---
include/net/ip_vs.h | 16 ++++
net/netfilter/ipvs/Kconfig | 7 +-
net/netfilter/ipvs/ip_vs_conn.c | 2
net/netfilter/ipvs/ip_vs_core.c | 173 ++++++++++++++++++++++++++++-----------
net/netfilter/ipvs/ip_vs_xmit.c | 24 ++++-
5 files changed, 161 insertions(+), 61 deletions(-)
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 8d5920f..50f377e 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -123,11 +123,27 @@ static inline struct sk_buff *skb_nfct_reasm(const struct
sk_buff *skb)
{
return skb->nfct_reasm;
}
+static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset,
+ int len, void *buffer,
+ const struct ip_vs_iphdr *ipvsh)
+{
+ if (unlikely(ipvsh->fragoffs && skb_nfct_reasm(skb)))
+ return skb_header_pointer(skb_nfct_reasm(skb), ipvsh->offs,
+ len, buffer);
+
+ return skb_header_pointer(skb, offset, len, buffer);
+}
#else
static inline struct sk_buff *skb_nfct_reasm(const struct sk_buff *skb)
{
return NULL;
}
+static inline void *frag_safe_skb_hp(const struct sk_buff *skb, int offset,
+ int len, void *buffer,
+ const struct ip_vs_iphdr *ipvsh)
+{
+ return skb_header_pointer(skb, offset, len, buffer);
+}
#endif
static inline void
diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
index 8b2cffd..0c3b167 100644
--- a/net/netfilter/ipvs/Kconfig
+++ b/net/netfilter/ipvs/Kconfig
@@ -28,12 +28,11 @@ if IP_VS
config IP_VS_IPV6
bool "IPv6 support for IPVS"
depends on IPV6 = y || IP_VS = IPV6
+ select IP6_NF_IPTABLES
---help---
- Add IPv6 support to IPVS. This is incomplete and might be dangerous.
+ Add IPv6 support to IPVS.
- See http://www.mindbasket.com/ipvs for more information.
-
- Say N if unsure.
+ Say Y if unsure.
config IP_VS_DEBUG
bool "IP virtual server debugging"
diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index a00db99..30e764a 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -313,7 +313,7 @@ ip_vs_conn_fill_param_proto(int af, const struct sk_buff
*skb,
__be16 _ports[2], *pptr;
struct net *net = skb_net(skb);
- pptr = skb_header_pointer(skb, iph->len, sizeof(_ports), _ports);
+ pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports, iph);
if (pptr == NULL)
return 1;
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 32c69ed..9f2e167 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -402,7 +402,7 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff
*skb,
/*
* IPv6 frags, only the first hit here.
*/
- pptr = skb_header_pointer(skb, iph->len, sizeof(_ports), _ports);
+ pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports, iph);
if (pptr == NULL)
return NULL;
@@ -505,7 +505,7 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff
*skb,
int unicast;
#endif
- pptr = skb_header_pointer(skb, iph->len, sizeof(_ports), _ports);
+ pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports, iph);
if (pptr == NULL) {
ip_vs_service_put(svc);
return NF_DROP;
@@ -651,14 +651,6 @@ static inline int ip_vs_gather_frags(struct sk_buff *skb,
u_int32_t user)
return err;
}
-#ifdef CONFIG_IP_VS_IPV6
-static inline int ip_vs_gather_frags_v6(struct sk_buff *skb, u_int32_t user)
-{
- /* TODO IPv6: Find out what to do here for IPv6 */
- return 0;
-}
-#endif
-
static int ip_vs_route_me_harder(int af, struct sk_buff *skb)
{
#ifdef CONFIG_IP_VS_IPV6
@@ -729,10 +721,22 @@ void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct
ip_vs_protocol *pp,
struct ip_vs_conn *cp, int inout)
{
struct ipv6hdr *iph = ipv6_hdr(skb);
- unsigned int icmp_offset = sizeof(struct ipv6hdr);
- struct icmp6hdr *icmph = (struct icmp6hdr *)(skb_network_header(skb) +
- icmp_offset);
- struct ipv6hdr *ciph = (struct ipv6hdr *)(icmph + 1);
+ unsigned int icmp_offset = 0;
+ unsigned int offs = 0; /* header offset*/
+ int protocol;
+ struct icmp6hdr *icmph;
+ struct ipv6hdr *ciph;
+ unsigned short fragoffs;
+
+ ipv6_find_hdr(skb, &icmp_offset, IPPROTO_ICMPV6, &fragoffs, NULL);
+ icmph = (struct icmp6hdr *)(skb_network_header(skb) + icmp_offset);
+ offs = icmp_offset + sizeof(struct icmp6hdr);
+ ciph = (struct ipv6hdr *)(skb_network_header(skb) + offs);
+
+ protocol = ipv6_find_hdr(skb, &offs, -1, &fragoffs, NULL);
+
+ if (!skb_make_writable(skb, offs + sizeof(__u32)))
+ return;
if (inout) {
iph->saddr = cp->vaddr.in6;
@@ -743,10 +747,13 @@ void ip_vs_nat_icmp_v6(struct sk_buff *skb, struct
ip_vs_protocol *pp,
}
/* the TCP/UDP/SCTP port */
- if (IPPROTO_TCP == ciph->nexthdr || IPPROTO_UDP == ciph->nexthdr ||
- IPPROTO_SCTP == ciph->nexthdr) {
- __be16 *ports = (void *)ciph + sizeof(struct ipv6hdr);
+ if (!fragoffs && (IPPROTO_TCP == protocol || IPPROTO_UDP == protocol ||
+ IPPROTO_SCTP == protocol)) {
+ __be16 *ports = (void *)(skb_network_header(skb) + offs);
+ IP_VS_DBG(11, "%s() changed port %d to %d\n", __func__,
+ ntohs(inout ? ports[1] : ports[0]),
+ ntohs(inout ? cp->vport : cp->dport));
if (inout)
ports[1] = cp->vport;
else
@@ -919,12 +926,12 @@ static int ip_vs_out_icmp_v6(struct sk_buff *skb, int
*related,
union nf_inet_addr snet;
*related = 1;
-
- ic = skb_header_pointer(skb, ipvsh->len, sizeof(_icmph), &_icmph);
+ ic = frag_safe_skb_hp(skb, ipvsh->len, sizeof(_icmph), &_icmph, ipvsh);
if (ic == NULL)
return NF_DROP;
- IP_VS_DBG(12, "Outgoing ICMPv6 (%d,%d) %pI6c->%pI6c\n",
+ IP_VS_DBG(12, "Outgoing ICMPv6 %s(%d,%d) %pI6c->%pI6c\n",
+ ipvsh->flags & IP6T_FH_F_FRAG ? "Fragment " : "",
ic->icmp6_type, ntohs(icmpv6_id(ic)),
&ipvsh->saddr, &ipvsh->daddr);
@@ -935,12 +942,15 @@ static int ip_vs_out_icmp_v6(struct sk_buff *skb, int
*related,
* this means that some packets will manage to get a long way
* down this stack and then be rejected, but that's life.
*/
- if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
- (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
- (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
+ if (ic->icmp6_type & ICMPV6_INFOMSG_MASK) {
*related = 0;
return NF_ACCEPT;
}
+ /* Fragment header that is before ICMP header tells us that:
+ * it's not an error message since they can't be fragmented.
+ */
+ if (ipvsh->flags & IP6T_FH_F_FRAG)
+ return NF_DROP;
/* Now find the contained IP header */
ipvsh->len += sizeof(_icmph);
@@ -1095,6 +1105,12 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int
af)
ip_vs_fill_iph_skb(af, skb, &iph);
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
+ if (!iph.fragoffs && skb_nfct_reasm(skb)) {
+ struct sk_buff *reasm = skb_nfct_reasm(skb);
+ /* Save fw mark for coming frags */
+ reasm->ipvs_property = 1;
+ reasm->mark = skb->mark;
+ }
if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
int related;
int verdict = ip_vs_out_icmp_v6(skb, &related,
@@ -1102,7 +1118,6 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int
af)
if (related)
return verdict;
- ip_vs_fill_iph_skb(af, skb, &iph);
}
} else
#endif
@@ -1112,7 +1127,6 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int
af)
if (related)
return verdict;
- ip_vs_fill_ip4hdr(skb_network_header(skb), &iph);
}
pd = ip_vs_proto_data_get(net, iph.protocol);
@@ -1145,8 +1159,8 @@ ip_vs_out(unsigned int hooknum, struct sk_buff *skb, int
af)
pp->protocol == IPPROTO_SCTP)) {
__be16 _ports[2], *pptr;
- pptr = skb_header_pointer(skb, iph.len,
- sizeof(_ports), _ports);
+ pptr = frag_safe_skb_hp(skb, iph.len,
+ sizeof(_ports), _ports, &iph);
if (pptr == NULL)
return NF_ACCEPT; /* Not for me */
if (ip_vs_lookup_real_service(net, af, iph.protocol,
@@ -1432,20 +1446,21 @@ static int ip_vs_in_icmp_v6(struct sk_buff *skb, int
*related,
unsigned int hooknum, struct ip_vs_iphdr *iph)
{
struct net *net = NULL;
+ const struct ipv6hdr _ip6h, *ip6h;
struct icmp6hdr _icmph, *ic;
struct ip_vs_iphdr ciph;
struct ip_vs_conn *cp;
struct ip_vs_protocol *pp;
struct ip_vs_proto_data *pd;
- unsigned int offset, verdict;
+ unsigned int offs_ciph, verdict;
*related = 1;
- ic = skb_header_pointer(skb, iph->len, sizeof(_icmph), &_icmph);
+ ic = frag_safe_skb_hp(skb, iph->len, sizeof(_icmph), &_icmph, iph);
if (ic == NULL)
return NF_DROP;
- IP_VS_DBG(12, "Incoming ICMPv6 (%d,%d) %pI6c->%pI6c\n",
+ IP_VS_DBG(12, "Incoming ICMPv6 %d(%d,%d) %pI6c->%pI6c\n", hooknum,
ic->icmp6_type, ntohs(icmpv6_id(ic)),
&iph->saddr, &iph->daddr);
@@ -1456,51 +1471,64 @@ static int ip_vs_in_icmp_v6(struct sk_buff *skb, int
*related,
* this means that some packets will manage to get a long way
* down this stack and then be rejected, but that's life.
*/
- if ((ic->icmp6_type != ICMPV6_DEST_UNREACH) &&
- (ic->icmp6_type != ICMPV6_PKT_TOOBIG) &&
- (ic->icmp6_type != ICMPV6_TIME_EXCEED)) {
+ if (ic->icmp6_type & ICMPV6_INFOMSG_MASK) {
*related = 0;
return NF_ACCEPT;
}
+ /* Fragment header that is before ICMP header tells us that:
+ * it's not an error message since they can't be fragmented.
+ */
+ if (iph->flags & IP6T_FH_F_FRAG)
+ return NF_DROP;
/* Now find the contained IP header */
ciph.len = iph->len + sizeof(_icmph);
ciph.flags = 0;
ciph.fragoffs = 0;
+ offs_ciph = ciph.len; /* Save ip header offset */
+ ip6h = skb_header_pointer(skb, ciph.len, sizeof(_ip6h),
+ (void *)&_ip6h);
ciph.protocol = ipv6_find_hdr(skb, &ciph.len, -1, &ciph.fragoffs,
&ciph.flags);
- ciph.saddr = iph->saddr; /* con_in_get() handles reverse order */
- ciph.daddr = iph->daddr;
+ ciph.saddr.in6 = ip6h->saddr; /* con_in_get() handles reverse order */
+ ciph.daddr.in6 = ip6h->daddr;
net = skb_net(skb);
pd = ip_vs_proto_data_get(net, ciph.protocol);
- if (!pd)
- return NF_ACCEPT;
- pp = pd->pp;
- /* Is the embedded protocol header present?
- * If it's the second or later fragment we don't know what it is
+ /* Is not the embedded protocol header present?
+ * or it's the second or later fragment we don't know what it is
* i.e. just let it through.
*/
- if (ciph.fragoffs)
+ if (!pd || ciph.fragoffs)
return NF_ACCEPT;
+ pp = pd->pp;
- offset = ciph.len;
- IP_VS_DBG_PKT(11, AF_INET6, pp, skb, offset,
+ IP_VS_DBG_PKT(11, AF_INET6, pp, skb, offs_ciph,
"Checking incoming ICMPv6 for");
- /* The embedded headers contain source and dest in reverse order */
- cp = pp->conn_in_get(AF_INET6, skb, &ciph, 1);
+ /* The embedded headers contain source and dest in reverse order
+ * if not from localhost
+ */
+ cp = pp->conn_in_get(AF_INET6, skb, &ciph,
+ (hooknum == NF_INET_LOCAL_OUT) ? 0 : 1);
+
if (!cp)
return NF_ACCEPT;
+ /* VS/TUN, VS/DR and LOCALNODE just let it go */
+ if ((hooknum == NF_INET_LOCAL_OUT) &&
+ (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)) {
+ __ip_vs_conn_put(cp);
+ return NF_ACCEPT;
+ }
/* do the statistics and put it back */
ip_vs_in_stats(cp, skb);
if (IPPROTO_TCP == ciph.protocol || IPPROTO_UDP == ciph.protocol ||
IPPROTO_SCTP == ciph.protocol)
- offset = ciph.len + (2 * sizeof(__u16));
+ offs_ciph = ciph.len;
- verdict = ip_vs_icmp_xmit_v6(skb, cp, pp, offset, hooknum, &ciph);
+ verdict = ip_vs_icmp_xmit_v6(skb, cp, pp, offs_ciph, hooknum, &ciph);
__ip_vs_conn_put(cp);
@@ -1562,6 +1590,12 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int
af)
#ifdef CONFIG_IP_VS_IPV6
if (af == AF_INET6) {
+ if (!iph.fragoffs && skb_nfct_reasm(skb)) {
+ struct sk_buff *reasm = skb_nfct_reasm(skb);
+ /* Save fw mark for coming frags. */
+ reasm->ipvs_property = 1;
+ reasm->mark = skb->mark;
+ }
if (unlikely(iph.protocol == IPPROTO_ICMPV6)) {
int related;
int verdict = ip_vs_in_icmp_v6(skb, &related, hooknum,
@@ -1587,12 +1621,12 @@ ip_vs_in(unsigned int hooknum, struct sk_buff *skb, int
af)
pp = pd->pp;
/*
* Check if the packet belongs to an existing connection entry
- * Only sched first IPv6 fragment.
*/
cp = pp->conn_in_get(af, skb, &iph, 0);
- if (unlikely(!cp) && !iph.fragoffs) {
+ if (unlikely(!cp)) {
int v;
+ /* Schedule and create new connection entry into &cp */
if (!pp->conn_schedule(af, skb, pd, &v, &cp, &iph))
return v;
}
@@ -1685,6 +1719,39 @@ ip_vs_local_request4(unsigned int hooknum, struct
sk_buff *skb,
#ifdef CONFIG_IP_VS_IPV6
/*
+ * AF_INET6 fragment handling
+ * Copy info from first fragment, to the rest of them.
+ */
+static unsigned int
+ip_vs_preroute_frag6(unsigned int hooknum, struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ int (*okfn)(struct sk_buff *))
+{
+ struct ip_vs_iphdr iphdr = { .len = 0, .flags = 0, };
+ struct sk_buff *reasm = skb_nfct_reasm(skb);
+ struct net *net;
+
+ /* Skip if not a "replay" from nf_ct_frag6_output or first fragment.
+ * ipvs_property is set when checking first fragment
+ * in ip_vs_in() and ip_vs_out().
+ */
+ if (reasm)
+ IP_VS_DBG(2, "Fragment recv prop:%d\n", reasm->ipvs_property);
+ if (!reasm || !reasm->ipvs_property)
+ return NF_ACCEPT;
+
+ net = skb_net(skb);
+ if (!net_ipvs(net)->enable)
+ return NF_ACCEPT;
+
+ /* Copy stored fw mark, saved in ip_vs_{in,out} */
+ skb->mark = reasm->mark;
+
+ return NF_ACCEPT;
+}
+
+/*
* AF_INET6 handler in NF_INET_LOCAL_IN chain
* Schedule and forward packets from remote clients
*/
@@ -1823,6 +1890,14 @@ static struct nf_hook_ops ip_vs_ops[] __read_mostly = {
.priority = 100,
},
#ifdef CONFIG_IP_VS_IPV6
+ /* After mangle & nat fetch 2:nd fragment and following */
+ {
+ .hook = ip_vs_preroute_frag6,
+ .owner = THIS_MODULE,
+ .pf = NFPROTO_IPV6,
+ .hooknum = NF_INET_PRE_ROUTING,
+ .priority = NF_IP6_PRI_NAT_DST + 1,
+ },
/* After packet filtering, change source only for VS/NAT */
{
.hook = ip_vs_reply6,
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 925cca2..422b92f 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -497,7 +497,9 @@ ip_vs_bypass_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
skb->dev = net->loopback_dev;
}
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ /* only send ICMP too big on first fragment */
+ if (!iph->fragoffs)
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
dst_release(&rt->dst);
IP_VS_DBG_RL("%s(): frag needed\n", __func__);
goto tx_error;
@@ -667,7 +669,7 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
EnterFunction(10);
/* check if it is a connection of no-client-port */
- if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) {
+ if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT && !iph->fragoffs)) {
__be16 _pt, *p;
p = skb_header_pointer(skb, iph->len, sizeof(_pt), &_pt);
if (p == NULL)
@@ -693,7 +695,7 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
if (ct && !nf_ct_is_untracked(ct)) {
IP_VS_DBG_RL_PKT(10, AF_INET6, pp, skb, 0,
- "ip_vs_nat_xmit_v6(): "
+ "ip_vs_nat_xmit_v6(): "\
"stopping DNAT to local address");
goto tx_error_put;
}
@@ -717,7 +719,9 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
skb->dev = net->loopback_dev;
}
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ /* only send ICMP too big on first fragment */
+ if (!iph->fragoffs)
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
IP_VS_DBG_RL_PKT(0, AF_INET6, pp, skb, 0,
"ip_vs_nat_xmit_v6(): frag needed for");
goto tx_error_put;
@@ -952,7 +956,9 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
skb->dev = net->loopback_dev;
}
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ /* only send ICMP too big on first fragment */
+ if (!ipvsh->fragoffs)
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
IP_VS_DBG_RL("%s(): frag needed\n", __func__);
goto tx_error_put;
}
@@ -1118,7 +1124,9 @@ ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
skb->dev = net->loopback_dev;
}
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ /* only send ICMP too big on first fragment */
+ if (!iph->fragoffs)
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
dst_release(&rt->dst);
IP_VS_DBG_RL("%s(): frag needed\n", __func__);
goto tx_error;
@@ -1356,7 +1364,9 @@ ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn
*cp,
skb->dev = net->loopback_dev;
}
- icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+ /* only send ICMP too big on first fragment */
+ if (!iph->fragoffs)
+ icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
IP_VS_DBG_RL("%s(): frag needed\n", __func__);
goto tx_error_put;
}
--
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