| Message ID | 20210125214430.24079-1-pchaudhary@linkedin.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,net-next,1/1] Allow user to set metric on default route learned via Router Advertisement. | expand |
On 1/25/21 2:44 PM, Praveen Chaudhary wrote: > For IPv4, default route is learned via DHCPv4 and user is allowed to change > metric using config etc/network/interfaces. But for IPv6, default route can > be learned via RA, for which, currently a fixed metric value 1024 is used. > > Ideally, user should be able to configure metric on default route for IPv6 > similar to IPv4. This fix adds sysctl for the same. > > Signed-off-by: Praveen Chaudhary <pchaudhary@linkedin.com> > Signed-off-by: Zhenggen Xu <zxu@linkedin.com> > > Reviewed-by: David Ahern <dsahern@kernel.org> > > Changes in v1. > 1.) Correct the call to rt6_add_dflt_router. > > Changes in v2. > 1.) Replace accept_ra_defrtr_metric to ra_defrtr_metric. > 2.) Change Type to __u32 instead of __s32. > 3.) Change description in Documentation/networking/ip-sysctl.rst. > 4.) Use proc_douintvec instead of proc_dointvec. > 5.) Code style in ndisc_router_discovery(). > 6.) Change Type to u32 instead of unsigned int. > > Changes in v3: > 1.) Removed '---' and '```' from description. > 2.) Remove stray ' after accept_ra_defrtr. > 3.) Fix tab in net/ipv6/addrconf.c. > > Changes in v4: > 1.) Remove special case of 0 and use IP6_RT_PRIO_USER as default. > 2.) Do not allow 0. > 3.) Change Documentation accordingly. > 4.) Remove extra brackets and compare with zero in ndisc_router_discovery(). > 5.) Remove compare with zero in rt6_add_dflt_router(). > > Logs: > > For IPv4: > > Config in etc/network/interfaces: > auto eth0 > iface eth0 inet dhcp > metric 4261413864 > > IPv4 Kernel Route Table: > $ ip route list > default via 172.21.47.1 dev eth0 metric 4261413864 > > FRR Table, if a static route is configured: > [In real scenario, it is useful to prefer BGP learned default route over DHCPv4 default route.] > Codes: K - kernel route, C - connected, S - static, R - RIP, > O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP, > T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > > - selected route, * - FIB route > > S>* 0.0.0.0/0 [20/0] is directly connected, eth0, 00:00:03 > K 0.0.0.0/0 [254/1000] via 172.21.47.1, eth0, 6d08h51m > > i.e. User can prefer Default Router learned via Routing Protocol in IPv4. > Similar behavior is not possible for IPv6, without this fix. > > After fix [for IPv6]: > sudo sysctl -w net.ipv6.conf.eth0.net.ipv6.conf.eth0.ra_defrtr_metric=1996489705 > > IP monitor: [When IPv6 RA is received] > default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 pref high > > Kernel IPv6 routing table > $ ip -6 route list > default via fe80::be16:65ff:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 21sec hoplimit 64 pref high > > FRR Table, if a static route is configured: > [In real scenario, it is useful to prefer BGP learned default route over IPv6 RA default route.] > Codes: K - kernel route, C - connected, S - static, R - RIPng, > O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table, > v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > > - selected route, * - FIB route > > S>* ::/0 [20/0] is directly connected, eth0, 00:00:06 > K ::/0 [119/1001] via fe80::xx16:xxxx:feb3:ce8e, eth0, 6d07h43m > > If the metric is changed later, the effect will be seen only when next IPv6 > RA is received, because the default route must be fully controlled by RA msg. > Below metric is changed from 1996489705 to 1996489704. > > $ sudo sysctl -w net.ipv6.conf.eth0.ra_defrtr_metric=1996489704 > net.ipv6.conf.eth0.ra_defrtr_metric = 1996489704 > > IP monitor: > [On next IPv6 RA msg, Kernel deletes prev route and installs new route with updated metric] > > Deleted default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 3sec hoplimit 64 pref high > default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489704 pref high > --- > Documentation/networking/ip-sysctl.rst | 10 ++++++++++ > include/linux/ipv6.h | 1 + > include/net/ip6_route.h | 3 ++- > include/uapi/linux/ipv6.h | 1 + > include/uapi/linux/sysctl.h | 1 + > net/ipv6/addrconf.c | 11 +++++++++++ > net/ipv6/ndisc.c | 12 ++++++++---- > net/ipv6/route.c | 5 +++-- > 8 files changed, 37 insertions(+), 7 deletions(-) > Reviewed-by: David Ahern <dsahern@kernel.org>
On Mon, 25 Jan 2021 20:34:56 -0700 David Ahern wrote: > On 1/25/21 2:44 PM, Praveen Chaudhary wrote: > > For IPv4, default route is learned via DHCPv4 and user is allowed to change > > metric using config etc/network/interfaces. But for IPv6, default route can > > be learned via RA, for which, currently a fixed metric value 1024 is used. > > > > Ideally, user should be able to configure metric on default route for IPv6 > > similar to IPv4. This fix adds sysctl for the same. > > > > Signed-off-by: Praveen Chaudhary <pchaudhary@linkedin.com> > > Signed-off-by: Zhenggen Xu <zxu@linkedin.com> > > > > Reviewed-by: David Ahern <dsahern@kernel.org> > > > > Changes in v1. > > 1.) Correct the call to rt6_add_dflt_router. > > > > Changes in v2. > > 1.) Replace accept_ra_defrtr_metric to ra_defrtr_metric. > > 2.) Change Type to __u32 instead of __s32. > > 3.) Change description in Documentation/networking/ip-sysctl.rst. > > 4.) Use proc_douintvec instead of proc_dointvec. > > 5.) Code style in ndisc_router_discovery(). > > 6.) Change Type to u32 instead of unsigned int. > > > > Changes in v3: > > 1.) Removed '---' and '```' from description. > > 2.) Remove stray ' after accept_ra_defrtr. > > 3.) Fix tab in net/ipv6/addrconf.c. > > > > Changes in v4: > > 1.) Remove special case of 0 and use IP6_RT_PRIO_USER as default. > > 2.) Do not allow 0. > > 3.) Change Documentation accordingly. > > 4.) Remove extra brackets and compare with zero in ndisc_router_discovery(). > > 5.) Remove compare with zero in rt6_add_dflt_router(). > > > > Logs: > > > > For IPv4: > > > > Config in etc/network/interfaces: > > auto eth0 > > iface eth0 inet dhcp > > metric 4261413864 > > > > IPv4 Kernel Route Table: > > $ ip route list > > default via 172.21.47.1 dev eth0 metric 4261413864 > > > > FRR Table, if a static route is configured: > > [In real scenario, it is useful to prefer BGP learned default route over DHCPv4 default route.] > > Codes: K - kernel route, C - connected, S - static, R - RIP, > > O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP, > > T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > > > - selected route, * - FIB route > > > > S>* 0.0.0.0/0 [20/0] is directly connected, eth0, 00:00:03 > > K 0.0.0.0/0 [254/1000] via 172.21.47.1, eth0, 6d08h51m > > > > i.e. User can prefer Default Router learned via Routing Protocol in IPv4. > > Similar behavior is not possible for IPv6, without this fix. > > > > After fix [for IPv6]: > > sudo sysctl -w net.ipv6.conf.eth0.net.ipv6.conf.eth0.ra_defrtr_metric=1996489705 > > > > IP monitor: [When IPv6 RA is received] > > default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 pref high > > > > Kernel IPv6 routing table > > $ ip -6 route list > > default via fe80::be16:65ff:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 21sec hoplimit 64 pref high > > > > FRR Table, if a static route is configured: > > [In real scenario, it is useful to prefer BGP learned default route over IPv6 RA default route.] > > Codes: K - kernel route, C - connected, S - static, R - RIPng, > > O - OSPFv3, I - IS-IS, B - BGP, N - NHRP, T - Table, > > v - VNC, V - VNC-Direct, A - Babel, D - SHARP, > > > - selected route, * - FIB route > > > > S>* ::/0 [20/0] is directly connected, eth0, 00:00:06 > > K ::/0 [119/1001] via fe80::xx16:xxxx:feb3:ce8e, eth0, 6d07h43m > > > > If the metric is changed later, the effect will be seen only when next IPv6 > > RA is received, because the default route must be fully controlled by RA msg. > > Below metric is changed from 1996489705 to 1996489704. > > > > $ sudo sysctl -w net.ipv6.conf.eth0.ra_defrtr_metric=1996489704 > > net.ipv6.conf.eth0.ra_defrtr_metric = 1996489704 > > > > IP monitor: > > [On next IPv6 RA msg, Kernel deletes prev route and installs new route with updated metric] > > > > Deleted default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489705 expires 3sec hoplimit 64 pref high > > default via fe80::xx16:xxxx:feb3:ce8e dev eth0 proto ra metric 1996489704 pref high > > --- > > Documentation/networking/ip-sysctl.rst | 10 ++++++++++ > > include/linux/ipv6.h | 1 + > > include/net/ip6_route.h | 3 ++- > > include/uapi/linux/ipv6.h | 1 + > > include/uapi/linux/sysctl.h | 1 + > > net/ipv6/addrconf.c | 11 +++++++++++ > > net/ipv6/ndisc.c | 12 ++++++++---- > > net/ipv6/route.c | 5 +++-- > > 8 files changed, 37 insertions(+), 7 deletions(-) > > > > Reviewed-by: David Ahern <dsahern@kernel.org> Did my best to untangle the commit message and applied. Thanks!
Hello: This patch was applied to netdev/net-next.git (refs/heads/master): On Mon, 25 Jan 2021 13:44:30 -0800 you wrote: > For IPv4, default route is learned via DHCPv4 and user is allowed to change > metric using config etc/network/interfaces. But for IPv6, default route can > be learned via RA, for which, currently a fixed metric value 1024 is used. > > Ideally, user should be able to configure metric on default route for IPv6 > similar to IPv4. This fix adds sysctl for the same. > > [...] Here is the summary with links: - [v4,net-next,1/1] Allow user to set metric on default route learned via Router Advertisement. https://git.kernel.org/netdev/net-next/c/6b2e04bc240f You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index dd2b12a32b73..0e51ddd9a2f1 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1871,6 +1871,16 @@ accept_ra_defrtr - BOOLEAN - enabled if accept_ra is enabled. - disabled if accept_ra is disabled. +ra_defrtr_metric - UNSIGNED INTEGER + Route metric for default route learned in Router Advertisement. This value + will be assigned as metric for the default route learned via IPv6 Router + Advertisement. Takes affect only if accept_ra_defrtr is enabled. + + Possible values: + 1 to 0xFFFFFFFF + + Default: IP6_RT_PRIO_USER i.e. 1024. + accept_ra_from_local - BOOLEAN Accept RA with source-address that is found on local machine if the RA is otherwise proper and able to be accepted. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index dda61d150a13..9d1f29f0c512 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -31,6 +31,7 @@ struct ipv6_devconf { __s32 max_desync_factor; __s32 max_addresses; __s32 accept_ra_defrtr; + __u32 ra_defrtr_metric; __s32 accept_ra_min_hop_limit; __s32 accept_ra_pinfo; __s32 ignore_routes_with_linkdown; diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 2a5277758379..f51a118bfce8 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -174,7 +174,8 @@ struct fib6_info *rt6_get_dflt_router(struct net *net, struct net_device *dev); struct fib6_info *rt6_add_dflt_router(struct net *net, const struct in6_addr *gwaddr, - struct net_device *dev, unsigned int pref); + struct net_device *dev, unsigned int pref, + u32 defrtr_usr_metric); void rt6_purge_dflt_routers(struct net *net); diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 13e8751bf24a..70603775fe91 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -189,6 +189,7 @@ enum { DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, DEVCONF_NDISC_TCLASS, DEVCONF_RPL_SEG_ENABLED, + DEVCONF_RA_DEFRTR_METRIC, DEVCONF_MAX }; diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 458179df9b27..1e05d3caa712 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -571,6 +571,7 @@ enum { NET_IPV6_ACCEPT_SOURCE_ROUTE=25, NET_IPV6_ACCEPT_RA_FROM_LOCAL=26, NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN=27, + NET_IPV6_RA_DEFRTR_METRIC=28, __NET_IPV6_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index eff2cacd5209..7aff1a81b7f5 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -205,6 +205,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .max_desync_factor = MAX_DESYNC_FACTOR, .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, + .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, @@ -260,6 +261,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .max_desync_factor = MAX_DESYNC_FACTOR, .max_addresses = IPV6_MAX_ADDRESSES, .accept_ra_defrtr = 1, + .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, .accept_ra_pinfo = 1, @@ -5475,6 +5477,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor; array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses; array[DEVCONF_ACCEPT_RA_DEFRTR] = cnf->accept_ra_defrtr; + array[DEVCONF_RA_DEFRTR_METRIC] = cnf->ra_defrtr_metric; array[DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT] = cnf->accept_ra_min_hop_limit; array[DEVCONF_ACCEPT_RA_PINFO] = cnf->accept_ra_pinfo; #ifdef CONFIG_IPV6_ROUTER_PREF @@ -6667,6 +6670,14 @@ static const struct ctl_table addrconf_sysctl[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "ra_defrtr_metric", + .data = &ipv6_devconf.ra_defrtr_metric, + .maxlen = sizeof(u32), + .mode = 0644, + .proc_handler = proc_douintvec_minmax, + .extra1 = (void *)SYSCTL_ONE, + }, { .procname = "accept_ra_min_hop_limit", .data = &ipv6_devconf.accept_ra_min_hop_limit, diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 76717478f173..c467c6419893 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1173,6 +1173,7 @@ static void ndisc_router_discovery(struct sk_buff *skb) struct neighbour *neigh = NULL; struct inet6_dev *in6_dev; struct fib6_info *rt = NULL; + u32 defrtr_usr_metric; struct net *net; int lifetime; struct ndisc_options ndopts; @@ -1303,18 +1304,21 @@ static void ndisc_router_discovery(struct sk_buff *skb) return; } } - if (rt && lifetime == 0) { + /* Set default route metric as specified by user */ + defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric; + /* delete the route if lifetime is 0 or if metric needs change */ + if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) { ip6_del_rt(net, rt, false); rt = NULL; } - ND_PRINTK(3, info, "RA: rt: %p lifetime: %d, for dev: %s\n", - rt, lifetime, skb->dev->name); + ND_PRINTK(3, info, "RA: rt: %p lifetime: %d, metric: %d, for dev: %s\n", + rt, lifetime, defrtr_usr_metric, skb->dev->name); if (!rt && lifetime) { ND_PRINTK(3, info, "RA: adding default router\n"); rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr, - skb->dev, pref); + skb->dev, pref, defrtr_usr_metric); if (!rt) { ND_PRINTK(0, err, "RA: %s failed to add default route\n", diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 188e114b29b4..41d8f801b75f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -4252,11 +4252,12 @@ struct fib6_info *rt6_get_dflt_router(struct net *net, struct fib6_info *rt6_add_dflt_router(struct net *net, const struct in6_addr *gwaddr, struct net_device *dev, - unsigned int pref) + unsigned int pref, + u32 defrtr_usr_metric) { struct fib6_config cfg = { .fc_table = l3mdev_fib_table(dev) ? : RT6_TABLE_DFLT, - .fc_metric = IP6_RT_PRIO_USER, + .fc_metric = defrtr_usr_metric, .fc_ifindex = dev->ifindex, .fc_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT | RTF_UP | RTF_EXPIRES | RTF_PREF(pref),