* [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update
@ 2016-04-11 22:29 Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 1/4] ipv6: datagram: Refactor flowi6 init codes to a new function Martin KaFai Lau
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Martin KaFai Lau @ 2016-04-11 22:29 UTC (permalink / raw)
To: netdev; +Cc: Cong Wang, Eric Dumazet, Wei Wang, Kernel Team
v2:
~ Protect __sk_dst_get() operations with rcu_read_lock in
release_cb() because another thread may do ip6_dst_store()
for a udp sk without taking the sk lock (e.g. in sendmsg).
~ Do a ipv6_addr_v4mapped(&sk->sk_v6_daddr) check before
calling ip6_datagram_dst_update() in patch 3 and 4. It is
similar to how __ip6_datagram_connect handles it.
~ One fix in ip6_datagram_dst_update() in patch 2. It needs
to check (np->flow_label & IPV6_FLOWLABEL_MASK) before
doing fl6_sock_lookup. I was confused with the naming
of IPV6_FLOWLABEL_MASK and IPV6_FLOWINFO_MASK.
~ Check dst->obsolete just on the safe side, although I think it
should at least have DST_OBSOLETE_FORCE_CHK by now.
~ Add Fixes tag to patch 3 and 4
~ Add some points from the previous discussion about holding
sk lock to the commit message in patch 3.
v1:
There is a case in connected UDP socket such that
getsockopt(IPV6_MTU) will return a stale MTU value. The reproducible
sequence could be the following:
1. Create a connected UDP socket
2. Send some datagrams out
3. Receive a ICMPV6_PKT_TOOBIG
4. No new outgoing datagrams to trigger the sk_dst_check()
logic to update the sk->sk_dst_cache.
5. getsockopt(IPV6_MTU) returns the mtu from the invalid
sk->sk_dst_cache instead of the newly created RTF_CACHE clone.
Patch 1 and 2 are the prep work.
Patch 3 and 4 are the fixes.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 net 1/4] ipv6: datagram: Refactor flowi6 init codes to a new function
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
@ 2016-04-11 22:29 ` Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 2/4] ipv6: datagram: Refactor dst lookup and update " Martin KaFai Lau
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Martin KaFai Lau @ 2016-04-11 22:29 UTC (permalink / raw)
To: netdev; +Cc: Cong Wang, Eric Dumazet, Wei Wang, Kernel Team
Move flowi6 init codes for connected datagram sk to a newly created
function ip6_datagram_flow_key_init().
Notes:
1. fl6_flowlabel is used instead of fl6.flowlabel in __ip6_datagram_connect
2. ipv6_addr_is_multicast(&fl6->daddr) is used instead of
(addr_type & IPV6_ADDR_MULTICAST) in ip6_datagram_flow_key_init()
This new function will be reused during pmtu update in the later patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
---
net/ipv6/datagram.c | 50 ++++++++++++++++++++++++++++++--------------------
1 file changed, 30 insertions(+), 20 deletions(-)
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 4281621..f07c1dd 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -40,6 +40,30 @@ static bool ipv6_mapped_addr_any(const struct in6_addr *a)
return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
}
+static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct ipv6_pinfo *np = inet6_sk(sk);
+
+ memset(fl6, 0, sizeof(*fl6));
+ fl6->flowi6_proto = sk->sk_protocol;
+ fl6->daddr = sk->sk_v6_daddr;
+ fl6->saddr = np->saddr;
+ fl6->flowi6_oif = sk->sk_bound_dev_if;
+ fl6->flowi6_mark = sk->sk_mark;
+ fl6->fl6_dport = inet->inet_dport;
+ fl6->fl6_sport = inet->inet_sport;
+ fl6->flowlabel = np->flow_label;
+
+ if (!fl6->flowi6_oif)
+ fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+
+ if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr))
+ fl6->flowi6_oif = np->mcast_oif;
+
+ security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
+}
+
static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
@@ -52,6 +76,7 @@ static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int a
struct ipv6_txoptions *opt;
int addr_type;
int err;
+ __be32 fl6_flowlabel = 0;
if (usin->sin6_family == AF_INET) {
if (__ipv6_only_sock(sk))
@@ -66,11 +91,10 @@ static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int a
if (usin->sin6_family != AF_INET6)
return -EAFNOSUPPORT;
- memset(&fl6, 0, sizeof(fl6));
if (np->sndflow) {
- fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
- if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
- flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
+ fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
+ if (fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
+ flowlabel = fl6_sock_lookup(sk, fl6_flowlabel);
if (!flowlabel)
return -EINVAL;
}
@@ -145,7 +169,7 @@ ipv4_connected:
}
sk->sk_v6_daddr = *daddr;
- np->flow_label = fl6.flowlabel;
+ np->flow_label = fl6_flowlabel;
inet->inet_dport = usin->sin6_port;
@@ -154,21 +178,7 @@ ipv4_connected:
* destination cache for it.
*/
- fl6.flowi6_proto = sk->sk_protocol;
- fl6.daddr = sk->sk_v6_daddr;
- fl6.saddr = np->saddr;
- fl6.flowi6_oif = sk->sk_bound_dev_if;
- fl6.flowi6_mark = sk->sk_mark;
- fl6.fl6_dport = inet->inet_dport;
- fl6.fl6_sport = inet->inet_sport;
-
- if (!fl6.flowi6_oif)
- fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
-
- if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
- fl6.flowi6_oif = np->mcast_oif;
-
- security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
+ ip6_datagram_flow_key_init(&fl6, sk);
rcu_read_lock();
opt = flowlabel ? flowlabel->opt : rcu_dereference(np->opt);
--
2.5.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 net 2/4] ipv6: datagram: Refactor dst lookup and update codes to a new function
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 1/4] ipv6: datagram: Refactor flowi6 init codes to a new function Martin KaFai Lau
@ 2016-04-11 22:29 ` Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 3/4] ipv6: datagram: Update dst cache of a connected datagram sk during pmtu update Martin KaFai Lau
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Martin KaFai Lau @ 2016-04-11 22:29 UTC (permalink / raw)
To: netdev; +Cc: Cong Wang, Eric Dumazet, Wei Wang, Kernel Team
This patch moves the route lookup and update codes for connected
datagram sk to a newly created function ip6_datagram_dst_update()
It will be reused during the pmtu update in the later patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
---
net/ipv6/datagram.c | 103 +++++++++++++++++++++++++++++-----------------------
1 file changed, 57 insertions(+), 46 deletions(-)
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index f07c1dd..669585e 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -64,16 +64,65 @@ static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
}
+static int ip6_datagram_dst_update(struct sock *sk)
+{
+ struct ip6_flowlabel *flowlabel = NULL;
+ struct in6_addr *final_p, final;
+ struct ipv6_txoptions *opt;
+ struct dst_entry *dst;
+ struct inet_sock *inet = inet_sk(sk);
+ struct ipv6_pinfo *np = inet6_sk(sk);
+ struct flowi6 fl6;
+ int err = 0;
+
+ if (np->sndflow && (np->flow_label & IPV6_FLOWLABEL_MASK)) {
+ flowlabel = fl6_sock_lookup(sk, np->flow_label);
+ if (!flowlabel)
+ return -EINVAL;
+ }
+ ip6_datagram_flow_key_init(&fl6, sk);
+
+ rcu_read_lock();
+ opt = flowlabel ? flowlabel->opt : rcu_dereference(np->opt);
+ final_p = fl6_update_dst(&fl6, opt, &final);
+ rcu_read_unlock();
+
+ dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
+ if (IS_ERR(dst)) {
+ err = PTR_ERR(dst);
+ goto out;
+ }
+
+ if (ipv6_addr_any(&np->saddr))
+ np->saddr = fl6.saddr;
+
+ if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
+ sk->sk_v6_rcv_saddr = fl6.saddr;
+ inet->inet_rcv_saddr = LOOPBACK4_IPV6;
+ if (sk->sk_prot->rehash)
+ sk->sk_prot->rehash(sk);
+ }
+
+ ip6_dst_store(sk, dst,
+ ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
+ &sk->sk_v6_daddr : NULL,
+#ifdef CONFIG_IPV6_SUBTREES
+ ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
+ &np->saddr :
+#endif
+ NULL);
+
+out:
+ fl6_sock_release(flowlabel);
+ return err;
+}
+
static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
struct inet_sock *inet = inet_sk(sk);
struct ipv6_pinfo *np = inet6_sk(sk);
- struct in6_addr *daddr, *final_p, final;
- struct dst_entry *dst;
- struct flowi6 fl6;
- struct ip6_flowlabel *flowlabel = NULL;
- struct ipv6_txoptions *opt;
+ struct in6_addr *daddr;
int addr_type;
int err;
__be32 fl6_flowlabel = 0;
@@ -91,14 +140,8 @@ static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int a
if (usin->sin6_family != AF_INET6)
return -EAFNOSUPPORT;
- if (np->sndflow) {
+ if (np->sndflow)
fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
- if (fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
- flowlabel = fl6_sock_lookup(sk, fl6_flowlabel);
- if (!flowlabel)
- return -EINVAL;
- }
- }
addr_type = ipv6_addr_type(&usin->sin6_addr);
@@ -178,45 +221,13 @@ ipv4_connected:
* destination cache for it.
*/
- ip6_datagram_flow_key_init(&fl6, sk);
-
- rcu_read_lock();
- opt = flowlabel ? flowlabel->opt : rcu_dereference(np->opt);
- final_p = fl6_update_dst(&fl6, opt, &final);
- rcu_read_unlock();
-
- dst = ip6_dst_lookup_flow(sk, &fl6, final_p);
- err = 0;
- if (IS_ERR(dst)) {
- err = PTR_ERR(dst);
+ err = ip6_datagram_dst_update(sk);
+ if (err)
goto out;
- }
-
- /* source address lookup done in ip6_dst_lookup */
-
- if (ipv6_addr_any(&np->saddr))
- np->saddr = fl6.saddr;
-
- if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
- sk->sk_v6_rcv_saddr = fl6.saddr;
- inet->inet_rcv_saddr = LOOPBACK4_IPV6;
- if (sk->sk_prot->rehash)
- sk->sk_prot->rehash(sk);
- }
-
- ip6_dst_store(sk, dst,
- ipv6_addr_equal(&fl6.daddr, &sk->sk_v6_daddr) ?
- &sk->sk_v6_daddr : NULL,
-#ifdef CONFIG_IPV6_SUBTREES
- ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
- &np->saddr :
-#endif
- NULL);
sk->sk_state = TCP_ESTABLISHED;
sk_set_txhash(sk);
out:
- fl6_sock_release(flowlabel);
return err;
}
--
2.5.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 net 3/4] ipv6: datagram: Update dst cache of a connected datagram sk during pmtu update
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 1/4] ipv6: datagram: Refactor flowi6 init codes to a new function Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 2/4] ipv6: datagram: Refactor dst lookup and update " Martin KaFai Lau
@ 2016-04-11 22:29 ` Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 4/4] ipv6: udp: Do a route lookup and update during release_cb Martin KaFai Lau
2016-04-14 20:45 ` [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update David Miller
4 siblings, 0 replies; 6+ messages in thread
From: Martin KaFai Lau @ 2016-04-11 22:29 UTC (permalink / raw)
To: netdev; +Cc: Cong Wang, Eric Dumazet, Wei Wang, Kernel Team
There is a case in connected UDP socket such that
getsockopt(IPV6_MTU) will return a stale MTU value. The reproducible
sequence could be the following:
1. Create a connected UDP socket
2. Send some datagrams out
3. Receive a ICMPV6_PKT_TOOBIG
4. No new outgoing datagrams to trigger the sk_dst_check()
logic to update the sk->sk_dst_cache.
5. getsockopt(IPV6_MTU) returns the mtu from the invalid
sk->sk_dst_cache instead of the newly created RTF_CACHE clone.
This patch updates the sk->sk_dst_cache for a connected datagram sk
during pmtu-update code path.
Note that the sk->sk_v6_daddr is used to do the route lookup
instead of skb->data (i.e. iph). It is because a UDP socket can become
connected after sending out some datagrams in un-connected state. or
It can be connected multiple times to different destinations. Hence,
iph may not be related to where sk is currently connected to.
It is done under '!sock_owned_by_user(sk)' condition because
the user may make another ip6_datagram_connect() (i.e changing
the sk->sk_v6_daddr) while dst lookup is happening in the pmtu-update
code path.
For the sock_owned_by_user(sk) == true case, the next patch will
introduce a release_cb() which will update the sk->sk_dst_cache.
Test:
Server (Connected UDP Socket):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Route Details:
[root@arch-fb-vm1 ~]# ip -6 r show | egrep '2fac'
2fac::/64 dev eth0 proto kernel metric 256 pref medium
2fac:face::/64 via 2fac::face dev eth0 metric 1024 pref medium
A simple python code to create a connected UDP socket:
import socket
import errno
HOST = '2fac::1'
PORT = 8080
s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
s.bind((HOST, PORT))
s.connect(('2fac:face::face', 53))
print("connected")
while True:
try:
data = s.recv(1024)
except socket.error as se:
if se.errno == errno.EMSGSIZE:
pmtu = s.getsockopt(41, 24)
print("PMTU:%d" % pmtu)
break
s.close()
Python program output after getting a ICMPV6_PKT_TOOBIG:
[root@arch-fb-vm1 ~]# python2 ~/devshare/kernel/tasks/fib6/udp-connect-53-8080.py
connected
PMTU:1300
Cache routes after recieving TOOBIG:
[root@arch-fb-vm1 ~]# ip -6 r show table cache
2fac:face::face via 2fac::face dev eth0 metric 0
cache expires 463sec mtu 1300 pref medium
Client (Send the ICMPV6_PKT_TOOBIG):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
scapy is used to generate the TOOBIG message. Here is the scapy script I have
used:
>>> p=Ether(src='da:75:4d:36:ac:32', dst='52:54:00:12:34:66', type=0x86dd)/IPv6(src='2fac::face', dst='2fac::1')/ICMPv6PacketTooBig(mtu=1300)/IPv6(src='2fac::
1',dst='2fac:face::face', nh='UDP')/UDP(sport=8080,dport=53)
>>> sendp(p, iface='qemubr0')
Fixes: 45e4fd26683c ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reported-by: Wei Wang <weiwan@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
---
include/net/ipv6.h | 1 +
net/ipv6/datagram.c | 20 +++++++++++---------
net/ipv6/route.c | 12 ++++++++++++
3 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index d0aeb97..fd02e90 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -959,6 +959,7 @@ int compat_ipv6_getsockopt(struct sock *sk, int level, int optname,
int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
int addr_len);
+int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr);
int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
int *addr_len);
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 669585e..59e01f27 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -64,7 +64,7 @@ static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
}
-static int ip6_datagram_dst_update(struct sock *sk)
+int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr)
{
struct ip6_flowlabel *flowlabel = NULL;
struct in6_addr *final_p, final;
@@ -93,14 +93,16 @@ static int ip6_datagram_dst_update(struct sock *sk)
goto out;
}
- if (ipv6_addr_any(&np->saddr))
- np->saddr = fl6.saddr;
+ if (fix_sk_saddr) {
+ if (ipv6_addr_any(&np->saddr))
+ np->saddr = fl6.saddr;
- if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
- sk->sk_v6_rcv_saddr = fl6.saddr;
- inet->inet_rcv_saddr = LOOPBACK4_IPV6;
- if (sk->sk_prot->rehash)
- sk->sk_prot->rehash(sk);
+ if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
+ sk->sk_v6_rcv_saddr = fl6.saddr;
+ inet->inet_rcv_saddr = LOOPBACK4_IPV6;
+ if (sk->sk_prot->rehash)
+ sk->sk_prot->rehash(sk);
+ }
}
ip6_dst_store(sk, dst,
@@ -221,7 +223,7 @@ ipv4_connected:
* destination cache for it.
*/
- err = ip6_datagram_dst_update(sk);
+ err = ip6_datagram_dst_update(sk, true);
if (err)
goto out;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1d8871a..d916d6a 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1418,8 +1418,20 @@ EXPORT_SYMBOL_GPL(ip6_update_pmtu);
void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu)
{
+ struct dst_entry *dst;
+
ip6_update_pmtu(skb, sock_net(sk), mtu,
sk->sk_bound_dev_if, sk->sk_mark);
+
+ dst = __sk_dst_get(sk);
+ if (!dst || !dst->obsolete ||
+ dst->ops->check(dst, inet6_sk(sk)->dst_cookie))
+ return;
+
+ bh_lock_sock(sk);
+ if (!sock_owned_by_user(sk) && !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+ ip6_datagram_dst_update(sk, false);
+ bh_unlock_sock(sk);
}
EXPORT_SYMBOL_GPL(ip6_sk_update_pmtu);
--
2.5.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 net 4/4] ipv6: udp: Do a route lookup and update during release_cb
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
` (2 preceding siblings ...)
2016-04-11 22:29 ` [PATCH v2 net 3/4] ipv6: datagram: Update dst cache of a connected datagram sk during pmtu update Martin KaFai Lau
@ 2016-04-11 22:29 ` Martin KaFai Lau
2016-04-14 20:45 ` [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update David Miller
4 siblings, 0 replies; 6+ messages in thread
From: Martin KaFai Lau @ 2016-04-11 22:29 UTC (permalink / raw)
To: netdev; +Cc: Cong Wang, Eric Dumazet, Wei Wang, Kernel Team
This patch adds a release_cb for UDPv6. It does a route lookup
and updates sk->sk_dst_cache if it is needed. It picks up the
left-over job from ip6_sk_update_pmtu() if the sk was owned
by user during the pmtu update.
It takes a rcu_read_lock to protect the __sk_dst_get() operations
because another thread may do ip6_dst_store() without taking the
sk lock (e.g. sendmsg).
Fixes: 45e4fd26683c ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reported-by: Wei Wang <weiwan@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
---
include/net/ipv6.h | 1 +
net/ipv6/datagram.c | 20 ++++++++++++++++++++
net/ipv6/udp.c | 1 +
3 files changed, 22 insertions(+)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index fd02e90..1be050a 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -960,6 +960,7 @@ int ip6_datagram_connect(struct sock *sk, struct sockaddr *addr, int addr_len);
int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *addr,
int addr_len);
int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr);
+void ip6_datagram_release_cb(struct sock *sk);
int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
int *addr_len);
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 59e01f27..9dd3882 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -119,6 +119,26 @@ out:
return err;
}
+void ip6_datagram_release_cb(struct sock *sk)
+{
+ struct dst_entry *dst;
+
+ if (ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+ return;
+
+ rcu_read_lock();
+ dst = __sk_dst_get(sk);
+ if (!dst || !dst->obsolete ||
+ dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {
+ rcu_read_unlock();
+ return;
+ }
+ rcu_read_unlock();
+
+ ip6_datagram_dst_update(sk, false);
+}
+EXPORT_SYMBOL_GPL(ip6_datagram_release_cb);
+
static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 8125931..6bc5c66 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1539,6 +1539,7 @@ struct proto udpv6_prot = {
.sendmsg = udpv6_sendmsg,
.recvmsg = udpv6_recvmsg,
.backlog_rcv = __udpv6_queue_rcv_skb,
+ .release_cb = ip6_datagram_release_cb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.rehash = udp_v6_rehash,
--
2.5.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
` (3 preceding siblings ...)
2016-04-11 22:29 ` [PATCH v2 net 4/4] ipv6: udp: Do a route lookup and update during release_cb Martin KaFai Lau
@ 2016-04-14 20:45 ` David Miller
4 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2016-04-14 20:45 UTC (permalink / raw)
To: kafai; +Cc: netdev, xiyou.wangcong, edumazet, weiwan, kernel-team
From: Martin KaFai Lau <kafai@fb.com>
Date: Mon, 11 Apr 2016 15:29:33 -0700
> v2:
> ~ Protect __sk_dst_get() operations with rcu_read_lock in
> release_cb() because another thread may do ip6_dst_store()
> for a udp sk without taking the sk lock (e.g. in sendmsg).
> ~ Do a ipv6_addr_v4mapped(&sk->sk_v6_daddr) check before
> calling ip6_datagram_dst_update() in patch 3 and 4. It is
> similar to how __ip6_datagram_connect handles it.
> ~ One fix in ip6_datagram_dst_update() in patch 2. It needs
> to check (np->flow_label & IPV6_FLOWLABEL_MASK) before
> doing fl6_sock_lookup. I was confused with the naming
> of IPV6_FLOWLABEL_MASK and IPV6_FLOWINFO_MASK.
> ~ Check dst->obsolete just on the safe side, although I think it
> should at least have DST_OBSOLETE_FORCE_CHK by now.
> ~ Add Fixes tag to patch 3 and 4
> ~ Add some points from the previous discussion about holding
> sk lock to the commit message in patch 3.
>
> v1:
> There is a case in connected UDP socket such that
> getsockopt(IPV6_MTU) will return a stale MTU value. The reproducible
> sequence could be the following:
> 1. Create a connected UDP socket
> 2. Send some datagrams out
> 3. Receive a ICMPV6_PKT_TOOBIG
> 4. No new outgoing datagrams to trigger the sk_dst_check()
> logic to update the sk->sk_dst_cache.
> 5. getsockopt(IPV6_MTU) returns the mtu from the invalid
> sk->sk_dst_cache instead of the newly created RTF_CACHE clone.
>
> Patch 1 and 2 are the prep work.
> Patch 3 and 4 are the fixes.
Series applied, thanks Martin.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-04-14 20:45 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-04-11 22:29 [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 1/4] ipv6: datagram: Refactor flowi6 init codes to a new function Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 2/4] ipv6: datagram: Refactor dst lookup and update " Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 3/4] ipv6: datagram: Update dst cache of a connected datagram sk during pmtu update Martin KaFai Lau
2016-04-11 22:29 ` [PATCH v2 net 4/4] ipv6: udp: Do a route lookup and update during release_cb Martin KaFai Lau
2016-04-14 20:45 ` [PATCH v2 net 0/4] ipv6: datagram: Update dst cache of a connected udp sk during pmtu update David Miller
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