| Message ID | 20221025222909.1112705-1-bpoirier@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | David Ahern |
| Headers | show |
| Series | [iproute2] ip-monitor: Do not error out when RTNLGRP_STATS is not available | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Wed, 26 Oct 2022 07:29:09 +0900 Benjamin Poirier <bpoirier@nvidia.com> wrote: > Following commit 4e8a9914c4d4 ("ip-monitor: Include stats events in default > and "all" cases"), `ip monitor` fails to start on kernels which do not > contain linux.git commit 5fd0b838efac ("net: rtnetlink: Add UAPI toggle for > IFLA_OFFLOAD_XSTATS_L3_STATS") because the netlink group RTNLGRP_STATS > doesn't exist: > > $ ip monitor > Failed to add stats group to list > > When "stats" is not explicitly requested, change the error to a warning so > that `ip monitor` and `ip monitor all` continue to work on older kernels. > > Note that the same change is not done for RTNLGRP_NEXTHOP because its value > is 32 and group numbers <= 32 are always supported; see the comment above > netlink_change_ngroups() in the kernel source. Therefore > NETLINK_ADD_MEMBERSHIP 32 does not error out even on kernels which do not > support RTNLGRP_NEXTHOP. > > Reported-by: Stephen Hemminger <stephen@networkplumber.org> > Fixes: 4e8a9914c4d4 ("ip-monitor: Include stats events in default and "all" cases") > Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com> > --- > ip/ipmonitor.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/ip/ipmonitor.c b/ip/ipmonitor.c > index 8a72ea42..45e4e8f1 100644 > --- a/ip/ipmonitor.c > +++ b/ip/ipmonitor.c > @@ -195,6 +195,8 @@ static int accept_msg(struct rtnl_ctrl_data *ctrl, > int do_ipmonitor(int argc, char **argv) > { > unsigned int groups = 0, lmask = 0; > + /* "needed" mask */ > + unsigned int nmask; > char *file = NULL; > int ifindex = 0; > > @@ -253,6 +255,7 @@ int do_ipmonitor(int argc, char **argv) > ipneigh_reset_filter(ifindex); > ipnetconf_reset_filter(ifindex); > > + nmask = lmask; > if (!lmask) > lmask = IPMON_L_ALL; > > @@ -328,8 +331,11 @@ int do_ipmonitor(int argc, char **argv) > > if (lmask & IPMON_LSTATS && > rtnl_add_nl_group(&rth, RTNLGRP_STATS) < 0) { > + if (!(nmask & IPMON_LSTATS)) > + fprintf(stderr, "Warning: "); > fprintf(stderr, "Failed to add stats group to list\n"); > - exit(1); > + if (nmask & IPMON_LSTATS) > + exit(1); > } > > if (listen_all_nsid && rtnl_listen_all_nsid(&rth) < 0) You still end up warning on older kernels. My version is simpler. All needs to not include lstats
On Wed, 26 Oct 2022 07:29:09 +0900 Benjamin Poirier <bpoirier@nvidia.com> wrote: > Following commit 4e8a9914c4d4 ("ip-monitor: Include stats events in default > and "all" cases"), `ip monitor` fails to start on kernels which do not > contain linux.git commit 5fd0b838efac ("net: rtnetlink: Add UAPI toggle for > IFLA_OFFLOAD_XSTATS_L3_STATS") because the netlink group RTNLGRP_STATS > doesn't exist: > > $ ip monitor > Failed to add stats group to list > > When "stats" is not explicitly requested, change the error to a warning so > that `ip monitor` and `ip monitor all` continue to work on older kernels. > > Note that the same change is not done for RTNLGRP_NEXTHOP because its value > is 32 and group numbers <= 32 are always supported; see the comment above > netlink_change_ngroups() in the kernel source. Therefore > NETLINK_ADD_MEMBERSHIP 32 does not error out even on kernels which do not > support RTNLGRP_NEXTHOP. > > Reported-by: Stephen Hemminger <stephen@networkplumber.org> > Fixes: 4e8a9914c4d4 ("ip-monitor: Include stats events in default and "all" cases") > Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com> There are two acceptable solutions: 1. Ignore the error, and never print any warning. 2. Don't ask for the stats feature with the default "ip monitor" and "ip monitor all" Either way, it needs to be totally silent when built and run on older kernels.
diff --git a/ip/ipmonitor.c b/ip/ipmonitor.c index 8a72ea42..45e4e8f1 100644 --- a/ip/ipmonitor.c +++ b/ip/ipmonitor.c @@ -195,6 +195,8 @@ static int accept_msg(struct rtnl_ctrl_data *ctrl, int do_ipmonitor(int argc, char **argv) { unsigned int groups = 0, lmask = 0; + /* "needed" mask */ + unsigned int nmask; char *file = NULL; int ifindex = 0; @@ -253,6 +255,7 @@ int do_ipmonitor(int argc, char **argv) ipneigh_reset_filter(ifindex); ipnetconf_reset_filter(ifindex); + nmask = lmask; if (!lmask) lmask = IPMON_L_ALL; @@ -328,8 +331,11 @@ int do_ipmonitor(int argc, char **argv) if (lmask & IPMON_LSTATS && rtnl_add_nl_group(&rth, RTNLGRP_STATS) < 0) { + if (!(nmask & IPMON_LSTATS)) + fprintf(stderr, "Warning: "); fprintf(stderr, "Failed to add stats group to list\n"); - exit(1); + if (nmask & IPMON_LSTATS) + exit(1); } if (listen_all_nsid && rtnl_listen_all_nsid(&rth) < 0)
Following commit 4e8a9914c4d4 ("ip-monitor: Include stats events in default and "all" cases"), `ip monitor` fails to start on kernels which do not contain linux.git commit 5fd0b838efac ("net: rtnetlink: Add UAPI toggle for IFLA_OFFLOAD_XSTATS_L3_STATS") because the netlink group RTNLGRP_STATS doesn't exist: $ ip monitor Failed to add stats group to list When "stats" is not explicitly requested, change the error to a warning so that `ip monitor` and `ip monitor all` continue to work on older kernels. Note that the same change is not done for RTNLGRP_NEXTHOP because its value is 32 and group numbers <= 32 are always supported; see the comment above netlink_change_ngroups() in the kernel source. Therefore NETLINK_ADD_MEMBERSHIP 32 does not error out even on kernels which do not support RTNLGRP_NEXTHOP. Reported-by: Stephen Hemminger <stephen@networkplumber.org> Fixes: 4e8a9914c4d4 ("ip-monitor: Include stats events in default and "all" cases") Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com> --- ip/ipmonitor.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)