* [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs
@ 2015-07-28 23:02 Tom Herbert
2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert
` (2 more replies)
0 siblings, 3 replies; 15+ messages in thread
From: Tom Herbert @ 2015-07-28 23:02 UTC (permalink / raw)
To: davem, netdev; +Cc: kernel-team
This patch set implements a common function to simply set sk_txhash to
a random number instead of going through the trouble to call flow
dissector. From dst_negative_advice we now reset the sk_txhash in hopes
of finding a better ECMP path through the network. Changing sk_txhash
affects:
- IPv6 flow label and UDP source port which affect ECMP in the network
- Local EMCP route selection (pending changes to use sk_txhash)
Tom Herbert (2):
net: Set sk_txhash from a random number
net: Recompute sk_txhash on negative routing advice
include/net/ip.h | 16 ----------------
include/net/ipv6.h | 19 -------------------
include/net/sock.h | 16 ++++++++++++++++
net/ipv4/datagram.c | 2 +-
net/ipv4/tcp_ipv4.c | 4 ++--
net/ipv6/datagram.c | 2 +-
net/ipv6/tcp_ipv6.c | 4 ++--
7 files changed, 22 insertions(+), 41 deletions(-)
--
1.8.1
^ permalink raw reply [flat|nested] 15+ messages in thread* [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-28 23:02 [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs Tom Herbert @ 2015-07-28 23:02 ` Tom Herbert 2015-07-29 9:13 ` Thomas Graf 2015-12-08 8:33 ` [net-next,1/2] " Alexander Drozdov 2015-07-28 23:02 ` [PATCH net-next 2/2] net: Recompute sk_txhash on negative routing advice Tom Herbert 2015-07-30 5:44 ` [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs David Miller 2 siblings, 2 replies; 15+ messages in thread From: Tom Herbert @ 2015-07-28 23:02 UTC (permalink / raw) To: davem, netdev; +Cc: kernel-team This patch creates sk_set_txhash and eliminates protocol specific inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a random number instead of performing flow dissection. sk_set_txash is also allowed to be called multiple times for the same socket, we'll need this when redoing the hash for negative routing advice. Signed-off-by: Tom Herbert <tom@herbertland.com> --- include/net/ip.h | 16 ---------------- include/net/ipv6.h | 19 ------------------- include/net/sock.h | 8 ++++++++ net/ipv4/datagram.c | 2 +- net/ipv4/tcp_ipv4.c | 4 ++-- net/ipv6/datagram.c | 2 +- net/ipv6/tcp_ipv6.c | 4 ++-- 7 files changed, 14 insertions(+), 41 deletions(-) diff --git a/include/net/ip.h b/include/net/ip.h index d5fe9f2..bee5f35 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -370,22 +370,6 @@ static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow, flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; } -static inline void inet_set_txhash(struct sock *sk) -{ - struct inet_sock *inet = inet_sk(sk); - struct flow_keys keys; - - memset(&keys, 0, sizeof(keys)); - - keys.addrs.v4addrs.src = inet->inet_saddr; - keys.addrs.v4addrs.dst = inet->inet_daddr; - keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; - keys.ports.src = inet->inet_sport; - keys.ports.dst = inet->inet_dport; - - sk->sk_txhash = flow_hash_from_keys(&keys); -} - static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto) { const struct iphdr *iph = skb_gro_network_header(skb); diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 82dbdb0..7c79798 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -707,25 +707,6 @@ static inline void iph_to_flow_copy_v6addrs(struct flow_keys *flow, } #if IS_ENABLED(CONFIG_IPV6) -static inline void ip6_set_txhash(struct sock *sk) -{ - struct inet_sock *inet = inet_sk(sk); - struct ipv6_pinfo *np = inet6_sk(sk); - struct flow_keys keys; - - memset(&keys, 0, sizeof(keys)); - - memcpy(&keys.addrs.v6addrs.src, &np->saddr, - sizeof(keys.addrs.v6addrs.src)); - memcpy(&keys.addrs.v6addrs.dst, &sk->sk_v6_daddr, - sizeof(keys.addrs.v6addrs.dst)); - keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; - keys.ports.src = inet->inet_sport; - keys.ports.dst = inet->inet_dport; - - sk->sk_txhash = flow_hash_from_keys(&keys); -} - static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb, __be32 flowlabel, bool autolabel) { diff --git a/include/net/sock.h b/include/net/sock.h index 4353ef7..fe735c4 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1687,6 +1687,14 @@ static inline void sock_graft(struct sock *sk, struct socket *parent) kuid_t sock_i_uid(struct sock *sk); unsigned long sock_i_ino(struct sock *sk); +static inline void sk_set_txhash(struct sock *sk) +{ + sk->sk_txhash = prandom_u32(); + + if (unlikely(!sk->sk_txhash)) + sk->sk_txhash = 1; +} + static inline struct dst_entry * __sk_dst_get(struct sock *sk) { diff --git a/net/ipv4/datagram.c b/net/ipv4/datagram.c index 574fad9..f915abf 100644 --- a/net/ipv4/datagram.c +++ b/net/ipv4/datagram.c @@ -74,7 +74,7 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len inet->inet_daddr = fl4->daddr; inet->inet_dport = usin->sin_port; sk->sk_state = TCP_ESTABLISHED; - inet_set_txhash(sk); + sk_set_txhash(sk); inet->inet_id = jiffies; sk_dst_set(sk, &rt->dst); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 486ba96..d27eb54 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -222,7 +222,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) if (err) goto failure; - inet_set_txhash(sk); + sk_set_txhash(sk); rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, inet->inet_sport, inet->inet_dport, sk); @@ -1277,7 +1277,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, newinet->mc_ttl = ip_hdr(skb)->ttl; newinet->rcv_tos = ip_hdr(skb)->tos; inet_csk(newsk)->icsk_ext_hdr_len = 0; - inet_set_txhash(newsk); + sk_set_txhash(newsk); if (inet_opt) inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; newinet->inet_id = newtp->write_seq ^ jiffies; diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c index 2572a32..9aadd57 100644 --- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -199,7 +199,7 @@ ipv4_connected: NULL); sk->sk_state = TCP_ESTABLISHED; - ip6_set_txhash(sk); + sk_set_txhash(sk); out: fl6_sock_release(flowlabel); return err; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index d540846..52dd0d9 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -276,7 +276,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, if (err) goto late_failure; - ip6_set_txhash(sk); + sk_set_txhash(sk); if (!tp->write_seq && likely(!tp->repair)) tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32, @@ -1090,7 +1090,7 @@ static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb, newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; newsk->sk_bound_dev_if = ireq->ir_iif; - ip6_set_txhash(newsk); + sk_set_txhash(newsk); /* Now IPv6 options... -- 1.8.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert @ 2015-07-29 9:13 ` Thomas Graf 2015-07-29 9:29 ` Eric Dumazet 2015-12-08 8:33 ` [net-next,1/2] " Alexander Drozdov 1 sibling, 1 reply; 15+ messages in thread From: Thomas Graf @ 2015-07-29 9:13 UTC (permalink / raw) To: Tom Herbert; +Cc: davem, netdev, kernel-team On 07/28/15 at 04:02pm, Tom Herbert wrote: > This patch creates sk_set_txhash and eliminates protocol specific > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a > random number instead of performing flow dissection. sk_set_txash > is also allowed to be called multiple times for the same socket, > we'll need this when redoing the hash for negative routing advice. > > Signed-off-by: Tom Herbert <tom@herbertland.com> Doesn't this break TX hashing with SO_REUSEPORT? ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 9:13 ` Thomas Graf @ 2015-07-29 9:29 ` Eric Dumazet 2015-07-29 9:54 ` Thomas Graf 0 siblings, 1 reply; 15+ messages in thread From: Eric Dumazet @ 2015-07-29 9:29 UTC (permalink / raw) To: Thomas Graf; +Cc: Tom Herbert, davem, netdev, kernel-team On Wed, 2015-07-29 at 11:13 +0200, Thomas Graf wrote: > On 07/28/15 at 04:02pm, Tom Herbert wrote: > > This patch creates sk_set_txhash and eliminates protocol specific > > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a > > random number instead of performing flow dissection. sk_set_txash > > is also allowed to be called multiple times for the same socket, > > we'll need this when redoing the hash for negative routing advice. > > > > Signed-off-by: Tom Herbert <tom@herbertland.com> > > Doesn't this break TX hashing with SO_REUSEPORT? AFAIK nothing uses sk_txhash yet. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 9:29 ` Eric Dumazet @ 2015-07-29 9:54 ` Thomas Graf 2015-07-29 10:06 ` Eric Dumazet 2015-07-29 15:58 ` Tom Herbert 0 siblings, 2 replies; 15+ messages in thread From: Thomas Graf @ 2015-07-29 9:54 UTC (permalink / raw) To: Eric Dumazet; +Cc: Tom Herbert, davem, netdev, kernel-team On 07/29/15 at 11:29am, Eric Dumazet wrote: > On Wed, 2015-07-29 at 11:13 +0200, Thomas Graf wrote: > > On 07/28/15 at 04:02pm, Tom Herbert wrote: > > > This patch creates sk_set_txhash and eliminates protocol specific > > > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a > > > random number instead of performing flow dissection. sk_set_txash > > > is also allowed to be called multiple times for the same socket, > > > we'll need this when redoing the hash for negative routing advice. > > > > > > Signed-off-by: Tom Herbert <tom@herbertland.com> > > > > Doesn't this break TX hashing with SO_REUSEPORT? > > > AFAIK nothing uses sk_txhash yet. skb_set_hash_from_sk() skb_get_hash() Am I misreading this? I'm not using SO_REUSEPORT and it might be OK to assume that different sockets may go to different queues even if the L4 tuple is identical. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 9:54 ` Thomas Graf @ 2015-07-29 10:06 ` Eric Dumazet 2015-07-29 10:47 ` Thomas Graf 2015-07-29 15:58 ` Tom Herbert 1 sibling, 1 reply; 15+ messages in thread From: Eric Dumazet @ 2015-07-29 10:06 UTC (permalink / raw) To: Thomas Graf; +Cc: Tom Herbert, davem, netdev, kernel-team On Wed, 2015-07-29 at 11:54 +0200, Thomas Graf wrote: > skb_set_hash_from_sk() > skb_get_hash() > > Am I misreading this? I'm not using SO_REUSEPORT and it might be OK > to assume that different sockets may go to different queues even if > the L4 tuple is identical. skb_set_hash_from_sk() sets skb->hash in output path. Nothing uses it then later. bonding uses its own hash functions. SO_REUSEPORT is on input path, and uses its own hash anyway. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 10:06 ` Eric Dumazet @ 2015-07-29 10:47 ` Thomas Graf 0 siblings, 0 replies; 15+ messages in thread From: Thomas Graf @ 2015-07-29 10:47 UTC (permalink / raw) To: Eric Dumazet; +Cc: Tom Herbert, davem, netdev, kernel-team On 07/29/15 at 12:06pm, Eric Dumazet wrote: > On Wed, 2015-07-29 at 11:54 +0200, Thomas Graf wrote: > > > skb_set_hash_from_sk() > > skb_get_hash() > > > > Am I misreading this? I'm not using SO_REUSEPORT and it might be OK > > to assume that different sockets may go to different queues even if > > the L4 tuple is identical. > > skb_set_hash_from_sk() sets skb->hash in output path. Nothing uses it > then later. bonding uses its own hash functions. > > SO_REUSEPORT is on input path, and uses its own hash anyway. Yes, I'm talking about the output path only but after further reading, the only case that could be a problem is if two SO_REUSEPORT sockets connect to the same destination address and port which will be prevented by connect anyway. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 9:54 ` Thomas Graf 2015-07-29 10:06 ` Eric Dumazet @ 2015-07-29 15:58 ` Tom Herbert 2015-07-29 20:02 ` Thomas Graf 1 sibling, 1 reply; 15+ messages in thread From: Tom Herbert @ 2015-07-29 15:58 UTC (permalink / raw) To: Thomas Graf Cc: Eric Dumazet, David S. Miller, Linux Kernel Network Developers, Kernel Team On Wed, Jul 29, 2015 at 2:54 AM, Thomas Graf <tgraf@suug.ch> wrote: > On 07/29/15 at 11:29am, Eric Dumazet wrote: >> On Wed, 2015-07-29 at 11:13 +0200, Thomas Graf wrote: >> > On 07/28/15 at 04:02pm, Tom Herbert wrote: >> > > This patch creates sk_set_txhash and eliminates protocol specific >> > > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a >> > > random number instead of performing flow dissection. sk_set_txash >> > > is also allowed to be called multiple times for the same socket, >> > > we'll need this when redoing the hash for negative routing advice. >> > > >> > > Signed-off-by: Tom Herbert <tom@herbertland.com> >> > >> > Doesn't this break TX hashing with SO_REUSEPORT? >> >> >> AFAIK nothing uses sk_txhash yet. > > skb_set_hash_from_sk() > skb_get_hash() > > Am I misreading this? I'm not using SO_REUSEPORT and it might be OK > to assume that different sockets may go to different queues even if > the L4 tuple is identical. Hi Thomas, The salient property of both sk_txhash and skb->hash is that they provide a uniform distribution over flows. It is incorrect to assume that either of these immutable during the lifetime of a flow, so yes this means that packets of a flow may go to different receive queues when hashes change. SO_REUSEPORT is a process in the receive path but uses ehashfn over the ports. But even with SO_REUSEPORT we provide no guarantee that packets of a "flow" will always hit the same socket, the hashing is not consistent when new reuseport sockets are added or removed-- this is actually a long standing issue with SO_REUSEPORT in the TCP case since it is possible to orphan connections in SYN-RECV. I believe Eric was working toward fixing that, so maybe in the future we can use skb->hash if it is a savings. Thanks, Tom ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 1/2] net: Set sk_txhash from a random number 2015-07-29 15:58 ` Tom Herbert @ 2015-07-29 20:02 ` Thomas Graf 0 siblings, 0 replies; 15+ messages in thread From: Thomas Graf @ 2015-07-29 20:02 UTC (permalink / raw) To: Tom Herbert Cc: Eric Dumazet, David S. Miller, Linux Kernel Network Developers, Kernel Team On 07/29/15 at 08:58am, Tom Herbert wrote: > The salient property of both sk_txhash and skb->hash is that they > provide a uniform distribution over flows. It is incorrect to assume > that either of these immutable during the lifetime of a flow, so yes > this means that packets of a flow may go to different receive queues > when hashes change. SO_REUSEPORT is a process in the receive path but > uses ehashfn over the ports. But even with SO_REUSEPORT we provide no > guarantee that packets of a "flow" will always hit the same socket, > the hashing is not consistent when new reuseport sockets are added or > removed-- this is actually a long standing issue with SO_REUSEPORT in > the TCP case since it is possible to orphan connections in SYN-RECV. I > believe Eric was working toward fixing that, so maybe in the future we > can use skb->hash if it is a savings. Thanks for the explanation. I have no objections to the changes then. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [net-next,1/2] net: Set sk_txhash from a random number 2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert 2015-07-29 9:13 ` Thomas Graf @ 2015-12-08 8:33 ` Alexander Drozdov 2015-12-08 13:15 ` Eric Dumazet 1 sibling, 1 reply; 15+ messages in thread From: Alexander Drozdov @ 2015-12-08 8:33 UTC (permalink / raw) To: Tom Herbert, davem, netdev; +Cc: kernel-team 29.07.2015 02:02, Tom Herbert wrote: > This patch creates sk_set_txhash and eliminates protocol specific > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a > random number instead of performing flow dissection. sk_set_txash > is also allowed to be called multiple times for the same socket, > we'll need this when redoing the hash for negative routing advice. It seems that this patch and some previous txhash-related ones break af_packet hash features for outgoing packets: - PACKET_FANOUT_HASH - TP_FT_REQ_FILL_RXHASH af_packet now thinks that hashes for for incoming and outgoing packets of the same TCP stream differ. That is true for TCP sessions initiated by the host. > > Signed-off-by: Tom Herbert <tom@herbertland.com> > --- > include/net/ip.h | 16 ---------------- > include/net/ipv6.h | 19 ------------------- > include/net/sock.h | 8 ++++++++ > net/ipv4/datagram.c | 2 +- > net/ipv4/tcp_ipv4.c | 4 ++-- > net/ipv6/datagram.c | 2 +- > net/ipv6/tcp_ipv6.c | 4 ++-- > 7 files changed, 14 insertions(+), 41 deletions(-) > > diff --git a/include/net/ip.h b/include/net/ip.h > index d5fe9f2..bee5f35 100644 > --- a/include/net/ip.h > +++ b/include/net/ip.h > @@ -370,22 +370,6 @@ static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow, > flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; > } > > -static inline void inet_set_txhash(struct sock *sk) > -{ > - struct inet_sock *inet = inet_sk(sk); > - struct flow_keys keys; > - > - memset(&keys, 0, sizeof(keys)); > - > - keys.addrs.v4addrs.src = inet->inet_saddr; > - keys.addrs.v4addrs.dst = inet->inet_daddr; > - keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS; > - keys.ports.src = inet->inet_sport; > - keys.ports.dst = inet->inet_dport; > - > - sk->sk_txhash = flow_hash_from_keys(&keys); > -} > - > static inline __wsum inet_gro_compute_pseudo(struct sk_buff *skb, int proto) > { > const struct iphdr *iph = skb_gro_network_header(skb); > diff --git a/include/net/ipv6.h b/include/net/ipv6.h > index 82dbdb0..7c79798 100644 > --- a/include/net/ipv6.h > +++ b/include/net/ipv6.h > @@ -707,25 +707,6 @@ static inline void iph_to_flow_copy_v6addrs(struct flow_keys *flow, > } > > #if IS_ENABLED(CONFIG_IPV6) > -static inline void ip6_set_txhash(struct sock *sk) > -{ > - struct inet_sock *inet = inet_sk(sk); > - struct ipv6_pinfo *np = inet6_sk(sk); > - struct flow_keys keys; > - > - memset(&keys, 0, sizeof(keys)); > - > - memcpy(&keys.addrs.v6addrs.src, &np->saddr, > - sizeof(keys.addrs.v6addrs.src)); > - memcpy(&keys.addrs.v6addrs.dst, &sk->sk_v6_daddr, > - sizeof(keys.addrs.v6addrs.dst)); > - keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS; > - keys.ports.src = inet->inet_sport; > - keys.ports.dst = inet->inet_dport; > - > - sk->sk_txhash = flow_hash_from_keys(&keys); > -} > - > static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb, > __be32 flowlabel, bool autolabel) > { > diff --git a/include/net/sock.h b/include/net/sock.h > index 4353ef7..fe735c4 100644 > --- a/include/net/sock.h > +++ b/include/net/sock.h > @@ -1687,6 +1687,14 @@ static inline void sock_graft(struct sock *sk, struct socket *parent) > kuid_t sock_i_uid(struct sock *sk); > unsigned long sock_i_ino(struct sock *sk); > > +static inline void sk_set_txhash(struct sock *sk) > +{ > + sk->sk_txhash = prandom_u32(); > + > + if (unlikely(!sk->sk_txhash)) > + sk->sk_txhash = 1; > +} > + > static inline struct dst_entry * > __sk_dst_get(struct sock *sk) > { > diff --git a/net/ipv4/datagram.c b/net/ipv4/datagram.c > index 574fad9..f915abf 100644 > --- a/net/ipv4/datagram.c > +++ b/net/ipv4/datagram.c > @@ -74,7 +74,7 @@ int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len > inet->inet_daddr = fl4->daddr; > inet->inet_dport = usin->sin_port; > sk->sk_state = TCP_ESTABLISHED; > - inet_set_txhash(sk); > + sk_set_txhash(sk); > inet->inet_id = jiffies; > > sk_dst_set(sk, &rt->dst); > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index 486ba96..d27eb54 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -222,7 +222,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) > if (err) > goto failure; > > - inet_set_txhash(sk); > + sk_set_txhash(sk); > > rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, > inet->inet_sport, inet->inet_dport, sk); > @@ -1277,7 +1277,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, > newinet->mc_ttl = ip_hdr(skb)->ttl; > newinet->rcv_tos = ip_hdr(skb)->tos; > inet_csk(newsk)->icsk_ext_hdr_len = 0; > - inet_set_txhash(newsk); > + sk_set_txhash(newsk); > if (inet_opt) > inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; > newinet->inet_id = newtp->write_seq ^ jiffies; > diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c > index 2572a32..9aadd57 100644 > --- a/net/ipv6/datagram.c > +++ b/net/ipv6/datagram.c > @@ -199,7 +199,7 @@ ipv4_connected: > NULL); > > sk->sk_state = TCP_ESTABLISHED; > - ip6_set_txhash(sk); > + sk_set_txhash(sk); > out: > fl6_sock_release(flowlabel); > return err; > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c > index d540846..52dd0d9 100644 > --- a/net/ipv6/tcp_ipv6.c > +++ b/net/ipv6/tcp_ipv6.c > @@ -276,7 +276,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, > if (err) > goto late_failure; > > - ip6_set_txhash(sk); > + sk_set_txhash(sk); > > if (!tp->write_seq && likely(!tp->repair)) > tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32, > @@ -1090,7 +1090,7 @@ static struct sock *tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb, > newsk->sk_v6_rcv_saddr = ireq->ir_v6_loc_addr; > newsk->sk_bound_dev_if = ireq->ir_iif; > > - ip6_set_txhash(newsk); > + sk_set_txhash(newsk); > > /* Now IPv6 options... > ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [net-next,1/2] net: Set sk_txhash from a random number 2015-12-08 8:33 ` [net-next,1/2] " Alexander Drozdov @ 2015-12-08 13:15 ` Eric Dumazet 2015-12-08 16:33 ` Tom Herbert 0 siblings, 1 reply; 15+ messages in thread From: Eric Dumazet @ 2015-12-08 13:15 UTC (permalink / raw) To: Alexander Drozdov; +Cc: Tom Herbert, davem, netdev, kernel-team On Tue, 2015-12-08 at 11:33 +0300, Alexander Drozdov wrote: > 29.07.2015 02:02, Tom Herbert wrote: > > This patch creates sk_set_txhash and eliminates protocol specific > > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a > > random number instead of performing flow dissection. sk_set_txash > > is also allowed to be called multiple times for the same socket, > > we'll need this when redoing the hash for negative routing advice. > It seems that this patch and some previous txhash-related > ones break af_packet hash features for outgoing packets: > - PACKET_FANOUT_HASH > - TP_FT_REQ_FILL_RXHASH > > af_packet now thinks that hashes for for incoming and outgoing > packets of the same TCP stream differ. That is true for TCP > sessions initiated by the host. There never has been such guarantee. Even rx hashes for a single TCP flow can differ, if packets are received on two different NIC with different RSSS keys. ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [net-next,1/2] net: Set sk_txhash from a random number 2015-12-08 13:15 ` Eric Dumazet @ 2015-12-08 16:33 ` Tom Herbert 2015-12-09 11:14 ` Alexander Drozdov 0 siblings, 1 reply; 15+ messages in thread From: Tom Herbert @ 2015-12-08 16:33 UTC (permalink / raw) To: Eric Dumazet Cc: Alexander Drozdov, David S. Miller, Linux Kernel Network Developers, Kernel Team On Tue, Dec 8, 2015 at 5:15 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > On Tue, 2015-12-08 at 11:33 +0300, Alexander Drozdov wrote: >> 29.07.2015 02:02, Tom Herbert wrote: >> > This patch creates sk_set_txhash and eliminates protocol specific >> > inet_set_txhash and ip6_set_txhash. sk_set_txhash simply sets a >> > random number instead of performing flow dissection. sk_set_txash >> > is also allowed to be called multiple times for the same socket, >> > we'll need this when redoing the hash for negative routing advice. >> It seems that this patch and some previous txhash-related >> ones break af_packet hash features for outgoing packets: >> - PACKET_FANOUT_HASH >> - TP_FT_REQ_FILL_RXHASH >> >> af_packet now thinks that hashes for for incoming and outgoing >> packets of the same TCP stream differ. That is true for TCP >> sessions initiated by the host. > > There never has been such guarantee. Even rx hashes for a single TCP > flow can differ, if packets are received on two different NIC with > different RSSS keys. > +1, it is a salient property that hashes can differ in each direction for a flow and that the hash for a flow can change over time. > > ^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [net-next,1/2] net: Set sk_txhash from a random number 2015-12-08 16:33 ` Tom Herbert @ 2015-12-09 11:14 ` Alexander Drozdov 0 siblings, 0 replies; 15+ messages in thread From: Alexander Drozdov @ 2015-12-09 11:14 UTC (permalink / raw) To: Tom Herbert, Eric Dumazet Cc: David S. Miller, Linux Kernel Network Developers, Kernel Team 08.12.2015 19:33, Tom Herbert wrote: > On Tue, Dec 8, 2015 at 5:15 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> There never has been such guarantee. Even rx hashes for a single TCP >> flow can differ, if packets are received on two different NIC with >> different RSSS keys. >> > +1, it is a salient property that hashes can differ in each direction > for a flow and that the hash for a flow can change over time. Thanks! I'll then try to move onto BPF fanout. ^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH net-next 2/2] net: Recompute sk_txhash on negative routing advice 2015-07-28 23:02 [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs Tom Herbert 2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert @ 2015-07-28 23:02 ` Tom Herbert 2015-07-30 5:44 ` [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs David Miller 2 siblings, 0 replies; 15+ messages in thread From: Tom Herbert @ 2015-07-28 23:02 UTC (permalink / raw) To: davem, netdev; +Cc: kernel-team When a connection is failing a transport protocol calls dst_negative_advice to try to get a better route. This patch includes changing the sk_txhash in that function. This provides a rudimentary method to try to find a different path in the network since sk_txhash affects ECMP on the local host and through the network (via flow labels or UDP source port in encapsulation). Signed-off-by: Tom Herbert <tom@herbertland.com> --- include/net/sock.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/include/net/sock.h b/include/net/sock.h index fe735c4..24aa75c 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1695,6 +1695,12 @@ static inline void sk_set_txhash(struct sock *sk) sk->sk_txhash = 1; } +static inline void sk_rethink_txhash(struct sock *sk) +{ + if (sk->sk_txhash) + sk_set_txhash(sk); +} + static inline struct dst_entry * __sk_dst_get(struct sock *sk) { @@ -1719,6 +1725,8 @@ static inline void dst_negative_advice(struct sock *sk) { struct dst_entry *ndst, *dst = __sk_dst_get(sk); + sk_rethink_txhash(sk); + if (dst && dst->ops->negative_advice) { ndst = dst->ops->negative_advice(dst); -- 1.8.1 ^ permalink raw reply related [flat|nested] 15+ messages in thread
* Re: [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs 2015-07-28 23:02 [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs Tom Herbert 2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert 2015-07-28 23:02 ` [PATCH net-next 2/2] net: Recompute sk_txhash on negative routing advice Tom Herbert @ 2015-07-30 5:44 ` David Miller 2 siblings, 0 replies; 15+ messages in thread From: David Miller @ 2015-07-30 5:44 UTC (permalink / raw) To: tom; +Cc: netdev, kernel-team From: Tom Herbert <tom@herbertland.com> Date: Tue, 28 Jul 2015 16:02:04 -0700 > This patch set implements a common function to simply set sk_txhash to > a random number instead of going through the trouble to call flow > dissector. From dst_negative_advice we now reset the sk_txhash in hopes > of finding a better ECMP path through the network. Changing sk_txhash > affects: > - IPv6 flow label and UDP source port which affect ECMP in the network > - Local EMCP route selection (pending changes to use sk_txhash) This looks fine, series applied, thanks Tom. ^ permalink raw reply [flat|nested] 15+ messages in thread
end of thread, other threads:[~2015-12-09 11:14 UTC | newest] Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-07-28 23:02 [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs Tom Herbert 2015-07-28 23:02 ` [PATCH net-next 1/2] net: Set sk_txhash from a random number Tom Herbert 2015-07-29 9:13 ` Thomas Graf 2015-07-29 9:29 ` Eric Dumazet 2015-07-29 9:54 ` Thomas Graf 2015-07-29 10:06 ` Eric Dumazet 2015-07-29 10:47 ` Thomas Graf 2015-07-29 15:58 ` Tom Herbert 2015-07-29 20:02 ` Thomas Graf 2015-12-08 8:33 ` [net-next,1/2] " Alexander Drozdov 2015-12-08 13:15 ` Eric Dumazet 2015-12-08 16:33 ` Tom Herbert 2015-12-09 11:14 ` Alexander Drozdov 2015-07-28 23:02 ` [PATCH net-next 2/2] net: Recompute sk_txhash on negative routing advice Tom Herbert 2015-07-30 5:44 ` [PATCH net-next 0/2] net: Initialize sk_hash to random value and reset for failing cnxs David Miller
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