| Message ID | c3fdfe3353158c9b9da14602619fb82db5e77f27.1650470610.git.gnault@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 16a28267774cd9f85405ef83d4afcbd0355e5817 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | ipv4: First steps toward removing RTO_ONLINK | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Series has a cover letter |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 3 this patch: 3 |
| netdev/cc_maintainers | success | CCed 6 of 6 maintainers |
| netdev/build_clang | success | Errors and warnings before: 9 this patch: 9 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 3 this patch: 3 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 10 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
On 4/20/22 5:21 PM, Guillaume Nault wrote: > All callers already initialise ->flowi4_scope with RT_SCOPE_UNIVERSE, > either by manual field assignment, memset(0) of the whole structure or > implicit structure initialisation of on-stack variables > (RT_SCOPE_UNIVERSE actually equals 0). > > Therefore, we don't need to always initialise ->flowi4_scope in > ip_rt_fix_tos(). We only need to reduce the scope to RT_SCOPE_LINK when > the special RTO_ONLINK flag is present in the tos. > > This will allow some code simplification, like removing > ip_rt_fix_tos(). Also, the long term idea is to remove RTO_ONLINK > entirely by properly initialising ->flowi4_scope, instead of > overloading ->flowi4_tos with a special flag. Eventually, this will > allow to convert ->flowi4_tos to dscp_t. > > Signed-off-by: Guillaume Nault <gnault@redhat.com> > --- > It's important for the correctness of this patch that all callers > initialise ->flowi4_scope to 0 (in one way or another). Auditing all of > them is long, although each case is pretty trivial. > > If it helps, I can send a patch series that converts implicit > initialisation of ->flowi4_scope with an explicit assignment to > RT_SCOPE_UNIVERSE. This would also have the advantage of making it > clear to future readers that ->flowi4_scope _has_ to be initialised. I > haven't sent such patch series to not overwhelm reviewers with trivial > and not technically-required changes (there are 40+ places to modify, > scattered over 30+ different files). But if anyone prefers explicit > initialisation everywhere, then just let me know and I'll send such > patches. There are a handful of places that open code the initialization of the flow struct. I *think* I found all of them in 40867d74c374. > --- > net/ipv4/route.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index e839d424b861..d8f82c0ac132 100644 > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -503,8 +503,8 @@ static void ip_rt_fix_tos(struct flowi4 *fl4) > __u8 tos = RT_FL_TOS(fl4); > > fl4->flowi4_tos = tos & IPTOS_RT_MASK; > - fl4->flowi4_scope = tos & RTO_ONLINK ? > - RT_SCOPE_LINK : RT_SCOPE_UNIVERSE; > + if (tos & RTO_ONLINK) > + fl4->flowi4_scope = RT_SCOPE_LINK; > } > > static void __build_flow_key(const struct net *net, struct flowi4 *fl4, Reviewed-by: David Ahern <dsahern@kernel.org>
On Thu, Apr 21, 2022 at 08:30:52PM -0600, David Ahern wrote: > On 4/20/22 5:21 PM, Guillaume Nault wrote: > > All callers already initialise ->flowi4_scope with RT_SCOPE_UNIVERSE, > > either by manual field assignment, memset(0) of the whole structure or > > implicit structure initialisation of on-stack variables > > (RT_SCOPE_UNIVERSE actually equals 0). > > > > Therefore, we don't need to always initialise ->flowi4_scope in > > ip_rt_fix_tos(). We only need to reduce the scope to RT_SCOPE_LINK when > > the special RTO_ONLINK flag is present in the tos. > > > > This will allow some code simplification, like removing > > ip_rt_fix_tos(). Also, the long term idea is to remove RTO_ONLINK > > entirely by properly initialising ->flowi4_scope, instead of > > overloading ->flowi4_tos with a special flag. Eventually, this will > > allow to convert ->flowi4_tos to dscp_t. > > > > Signed-off-by: Guillaume Nault <gnault@redhat.com> > > --- > > It's important for the correctness of this patch that all callers > > initialise ->flowi4_scope to 0 (in one way or another). Auditing all of > > them is long, although each case is pretty trivial. > > > > If it helps, I can send a patch series that converts implicit > > initialisation of ->flowi4_scope with an explicit assignment to > > RT_SCOPE_UNIVERSE. This would also have the advantage of making it > > clear to future readers that ->flowi4_scope _has_ to be initialised. I > > haven't sent such patch series to not overwhelm reviewers with trivial > > and not technically-required changes (there are 40+ places to modify, > > scattered over 30+ different files). But if anyone prefers explicit > > initialisation everywhere, then just let me know and I'll send such > > patches. > > There are a handful of places that open code the initialization of the > flow struct. I *think* I found all of them in 40867d74c374. By open code, do you mean "doesn't use flowi4_init_output() nor ip_tunnel_init_flow()"? If so, I think there are many more. To be sure we're on the same page, here's a small part of the diff for my "explicit flowi4_scope initialisation" patch series: drivers/infiniband/core/addr.c | 1 + drivers/infiniband/sw/rxe/rxe_net.c | 1 + drivers/net/amt.c | 3 +++ drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c | 1 + drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 3 +++ drivers/net/ethernet/netronome/nfp/flower/action.c | 1 + drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c | 7 +++++-- drivers/net/geneve.c | 9 +++++++-- drivers/net/gtp.c | 1 + drivers/net/ipvlan/ipvlan_core.c | 1 + drivers/net/vrf.c | 1 + drivers/net/vxlan/vxlan_core.c | 1 + drivers/net/wireguard/socket.c | 1 + include/net/ip_tunnels.h | 1 + include/net/route.h | 2 ++ net/core/filter.c | 1 + net/core/lwt_bpf.c | 1 + net/dccp/ipv4.c | 1 + net/ipv4/icmp.c | 3 +++ net/ipv4/netfilter.c | 1 + net/ipv4/netfilter/nf_reject_ipv4.c | 1 + net/ipv4/route.c | 1 + net/ipv4/xfrm4_policy.c | 1 + net/netfilter/ipvs/ip_vs_xmit.c | 1 + net/netfilter/nf_conntrack_h323_main.c | 3 +++ net/netfilter/nf_conntrack_sip.c | 1 + net/netfilter/nft_flow_offload.c | 1 + net/netfilter/nft_rt.c | 1 + net/netfilter/xt_TCPMSS.c | 2 ++ net/sctp/protocol.c | 1 + net/smc/smc_ib.c | 1 + net/tipc/udp_media.c | 1 + net/xfrm/xfrm_policy.c | 1 + 33 files changed, 53 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index f253295795f0..5b6e0003eead 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -399,6 +399,7 @@ static int addr4_resolve(struct sockaddr *src_sock, memset(&fl4, 0, sizeof(fl4)); fl4.daddr = dst_ip; fl4.saddr = src_ip; + fl4.flowi4_scope = RT_SCOPE_UNIVERSE; fl4.flowi4_oif = addr->bound_dev_if; rt = ip_route_output_key(addr->net, &fl4); ret = PTR_ERR_OR_ZERO(rt); diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c index c53f4529f098..cf6dc89a8785 100644 --- a/drivers/infiniband/sw/rxe/rxe_net.c +++ b/drivers/infiniband/sw/rxe/rxe_net.c @@ -31,6 +31,7 @@ static struct dst_entry *rxe_find_route4(struct net_device *ndev, fl.flowi4_oif = ndev->ifindex; memcpy(&fl.saddr, saddr, sizeof(*saddr)); memcpy(&fl.daddr, daddr, sizeof(*daddr)); + fl.flowi4_scope = RT_SCOPE_UNIVERSE; fl.flowi4_proto = IPPROTO_UDP; rt = ip_route_output_key(&init_net, &fl); diff --git a/drivers/net/amt.c b/drivers/net/amt.c index 10455c9b9da0..3e957ff64715 100644 --- a/drivers/net/amt.c +++ b/drivers/net/amt.c @@ -990,6 +990,7 @@ static bool amt_send_membership_update(struct amt_dev *amt, fl4.daddr = amt->remote_ip; fl4.saddr = amt->local_ip; fl4.flowi4_tos = AMT_TOS; + fl4.flowi4_scope = RT_SCOPE_UNIVERSE; fl4.flowi4_proto = IPPROTO_UDP; rt = ip_route_output_key(amt->net, &fl4); if (IS_ERR(rt)) { @@ -1048,6 +1049,7 @@ static void amt_send_multicast_data(struct amt_dev *amt, fl4.flowi4_oif = amt->stream_dev->ifindex; fl4.daddr = tunnel->ip4; fl4.saddr = amt->local_ip; + fl4.flowi4_scope = RT_SCOPE_UNIVERSE; fl4.flowi4_proto = IPPROTO_UDP; rt = ip_route_output_key(amt->net, &fl4); if (IS_ERR(rt)) { @@ -1103,6 +1105,7 @@ static bool amt_send_membership_query(struct amt_dev *amt, fl4.daddr = tunnel->ip4; fl4.saddr = amt->local_ip; fl4.flowi4_tos = AMT_TOS; + fl4.flowi4_scope = RT_SCOPE_UNIVERSE; fl4.flowi4_proto = IPPROTO_UDP; rt = ip_route_output_key(amt->net, &fl4); if (IS_ERR(rt)) { ... > > --- > > net/ipv4/route.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > > index e839d424b861..d8f82c0ac132 100644 > > --- a/net/ipv4/route.c > > +++ b/net/ipv4/route.c > > @@ -503,8 +503,8 @@ static void ip_rt_fix_tos(struct flowi4 *fl4) > > __u8 tos = RT_FL_TOS(fl4); > > > > fl4->flowi4_tos = tos & IPTOS_RT_MASK; > > - fl4->flowi4_scope = tos & RTO_ONLINK ? > > - RT_SCOPE_LINK : RT_SCOPE_UNIVERSE; > > + if (tos & RTO_ONLINK) > > + fl4->flowi4_scope = RT_SCOPE_LINK; > > } > > > > static void __build_flow_key(const struct net *net, struct flowi4 *fl4, > > Reviewed-by: David Ahern <dsahern@kernel.org> >
On 4/22/22 4:53 AM, Guillaume Nault wrote: > On Thu, Apr 21, 2022 at 08:30:52PM -0600, David Ahern wrote: >> On 4/20/22 5:21 PM, Guillaume Nault wrote: >>> All callers already initialise ->flowi4_scope with RT_SCOPE_UNIVERSE, >>> either by manual field assignment, memset(0) of the whole structure or >>> implicit structure initialisation of on-stack variables >>> (RT_SCOPE_UNIVERSE actually equals 0). >>> >>> Therefore, we don't need to always initialise ->flowi4_scope in >>> ip_rt_fix_tos(). We only need to reduce the scope to RT_SCOPE_LINK when >>> the special RTO_ONLINK flag is present in the tos. >>> >>> This will allow some code simplification, like removing >>> ip_rt_fix_tos(). Also, the long term idea is to remove RTO_ONLINK >>> entirely by properly initialising ->flowi4_scope, instead of >>> overloading ->flowi4_tos with a special flag. Eventually, this will >>> allow to convert ->flowi4_tos to dscp_t. >>> >>> Signed-off-by: Guillaume Nault <gnault@redhat.com> >>> --- >>> It's important for the correctness of this patch that all callers >>> initialise ->flowi4_scope to 0 (in one way or another). Auditing all of >>> them is long, although each case is pretty trivial. >>> >>> If it helps, I can send a patch series that converts implicit >>> initialisation of ->flowi4_scope with an explicit assignment to >>> RT_SCOPE_UNIVERSE. This would also have the advantage of making it >>> clear to future readers that ->flowi4_scope _has_ to be initialised. I >>> haven't sent such patch series to not overwhelm reviewers with trivial >>> and not technically-required changes (there are 40+ places to modify, >>> scattered over 30+ different files). But if anyone prefers explicit >>> initialisation everywhere, then just let me know and I'll send such >>> patches. >> >> There are a handful of places that open code the initialization of the >> flow struct. I *think* I found all of them in 40867d74c374. > > By open code, do you mean "doesn't use flowi4_init_output() nor > ip_tunnel_init_flow()"? If so, I think there are many more. > no, you made a comment about flow struct being initialized to 0 which implicitly initializes scope. My comment is that there are only a few places that do not use either `memset(flow, 0, sizeof())` or `struct flowi4 fl4 = {}` to fully initialize the struct.
On Fri, Apr 22, 2022 at 08:40:01AM -0600, David Ahern wrote: > On 4/22/22 4:53 AM, Guillaume Nault wrote: > > On Thu, Apr 21, 2022 at 08:30:52PM -0600, David Ahern wrote: > >> On 4/20/22 5:21 PM, Guillaume Nault wrote: > >>> All callers already initialise ->flowi4_scope with RT_SCOPE_UNIVERSE, > >>> either by manual field assignment, memset(0) of the whole structure or > >>> implicit structure initialisation of on-stack variables > >>> (RT_SCOPE_UNIVERSE actually equals 0). > >>> > >>> Therefore, we don't need to always initialise ->flowi4_scope in > >>> ip_rt_fix_tos(). We only need to reduce the scope to RT_SCOPE_LINK when > >>> the special RTO_ONLINK flag is present in the tos. > >>> > >>> This will allow some code simplification, like removing > >>> ip_rt_fix_tos(). Also, the long term idea is to remove RTO_ONLINK > >>> entirely by properly initialising ->flowi4_scope, instead of > >>> overloading ->flowi4_tos with a special flag. Eventually, this will > >>> allow to convert ->flowi4_tos to dscp_t. > >>> > >>> Signed-off-by: Guillaume Nault <gnault@redhat.com> > >>> --- > >>> It's important for the correctness of this patch that all callers > >>> initialise ->flowi4_scope to 0 (in one way or another). Auditing all of > >>> them is long, although each case is pretty trivial. > >>> > >>> If it helps, I can send a patch series that converts implicit > >>> initialisation of ->flowi4_scope with an explicit assignment to > >>> RT_SCOPE_UNIVERSE. This would also have the advantage of making it > >>> clear to future readers that ->flowi4_scope _has_ to be initialised. I > >>> haven't sent such patch series to not overwhelm reviewers with trivial > >>> and not technically-required changes (there are 40+ places to modify, > >>> scattered over 30+ different files). But if anyone prefers explicit > >>> initialisation everywhere, then just let me know and I'll send such > >>> patches. > >> > >> There are a handful of places that open code the initialization of the > >> flow struct. I *think* I found all of them in 40867d74c374. > > > > By open code, do you mean "doesn't use flowi4_init_output() nor > > ip_tunnel_init_flow()"? If so, I think there are many more. > > > > no, you made a comment about flow struct being initialized to 0 which > implicitly initializes scope. My comment is that there are only a few > places that do not use either `memset(flow, 0, sizeof())` or `struct > flowi4 fl4 = {}` to fully initialize the struct. Yes, that's right. But I've only audited the call paths that lead to ip_route_output_key_hash() (plus the ICMP error handlers), as these are the ones that were relevant for this patch series. So I haven't looked at flow initialisation in the ip_route_input*() or IPv6 call paths.
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index e839d424b861..d8f82c0ac132 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -503,8 +503,8 @@ static void ip_rt_fix_tos(struct flowi4 *fl4) __u8 tos = RT_FL_TOS(fl4); fl4->flowi4_tos = tos & IPTOS_RT_MASK; - fl4->flowi4_scope = tos & RTO_ONLINK ? - RT_SCOPE_LINK : RT_SCOPE_UNIVERSE; + if (tos & RTO_ONLINK) + fl4->flowi4_scope = RT_SCOPE_LINK; } static void __build_flow_key(const struct net *net, struct flowi4 *fl4,
All callers already initialise ->flowi4_scope with RT_SCOPE_UNIVERSE, either by manual field assignment, memset(0) of the whole structure or implicit structure initialisation of on-stack variables (RT_SCOPE_UNIVERSE actually equals 0). Therefore, we don't need to always initialise ->flowi4_scope in ip_rt_fix_tos(). We only need to reduce the scope to RT_SCOPE_LINK when the special RTO_ONLINK flag is present in the tos. This will allow some code simplification, like removing ip_rt_fix_tos(). Also, the long term idea is to remove RTO_ONLINK entirely by properly initialising ->flowi4_scope, instead of overloading ->flowi4_tos with a special flag. Eventually, this will allow to convert ->flowi4_tos to dscp_t. Signed-off-by: Guillaume Nault <gnault@redhat.com> --- It's important for the correctness of this patch that all callers initialise ->flowi4_scope to 0 (in one way or another). Auditing all of them is long, although each case is pretty trivial. If it helps, I can send a patch series that converts implicit initialisation of ->flowi4_scope with an explicit assignment to RT_SCOPE_UNIVERSE. This would also have the advantage of making it clear to future readers that ->flowi4_scope _has_ to be initialised. I haven't sent such patch series to not overwhelm reviewers with trivial and not technically-required changes (there are 40+ places to modify, scattered over 30+ different files). But if anyone prefers explicit initialisation everywhere, then just let me know and I'll send such patches. --- net/ipv4/route.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)