net: add sysctl accept_ra_min_lft
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cover net: add sysctl accept_ra_min_lft
Hi Greg & Sasha,
I am following up on https://lore.kernel.org/stable/[email protected]/ with cherry-picks for 5.15.135 and 5.10.198. Note that they also cleanly apply to 5.4.258, 4.19.296, and 4.14.327. I have run our test suite against all of these branches with the changes applied -- all passed.
I have skipped the UAPI portions in the first two patches as these are not actually necessary to get the sysctls working. The rest of the patches applied cleanly.
Thanks!
-Patrick
Patrick Rohr (3):
net: add sysctl accept_ra_min_rtr_lft
net: change accept_ra_min_rtr_lft to affect all RA lifetimes
net: release reference to inet6_dev pointer
Documentation/networking/ip-sysctl.rst | 8 ++++++++ include/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 12 ++++++++++++ net/ipv6/ndisc.c | 13 +++++++++++-- 4 files changed, 32 insertions(+), 2 deletions(-)
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2.42.0.655.g421f12c284-goog
PATCH 1/3 net: add sysctl accept_ra_min_rtr_lft
commit 1671bcfd76fdc0b9e65153cf759153083755fe4c upstream.
(Backported without unnecessary UAPI portion.)
This change adds a new sysctl accept_ra_min_rtr_lft to specify the minimum acceptable router lifetime in an RA. If the received RA router lifetime is less than the configured value (and not 0), the RA is ignored.
This is useful for mobile devices, whose battery life can be impacted by networks that configure RAs with a short lifetime. On such networks, the device should never gain IPv6 provisioning and should attempt to drop RAs via hardware offload, if available.
--- Documentation/networking/ip-sysctl.rst | 8 ++++++++ include/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 9 +++++++++ net/ipv6/ndisc.c | 18 ++++++++++++++++-- 4 files changed, 34 insertions(+), 2 deletions(-)
Documentation/networking/ip-sysctl.rst +8 -0
@@ -2070,6 +2070,14 @@ accept_ra_min_hop_limit - INTEGER Default: 1 +accept_ra_min_rtr_lft - INTEGER + Minimum acceptable router lifetime in Router Advertisement. + + RAs with a router lifetime less than this value shall be + ignored. RAs with a router lifetime of 0 are unaffected. + + Default: 0 + accept_ra_pinfo - BOOLEAN Learn Prefix Information in Router Advertisement.
include/linux/ipv6.h +1 -0
@@ -33,6 +33,7 @@ struct ipv6_devconf {__s32 accept_ra_defrtr;__u32 ra_defrtr_metric;__s32 accept_ra_min_hop_limit; +__s32 accept_ra_min_rtr_lft;__s32 accept_ra_pinfo;__s32 ignore_routes_with_linkdown;#ifdef CONFIG_IPV6_ROUTER_PREF
net/ipv6/addrconf.c +9 -0
@@ -209,6 +209,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, + .accept_ra_min_rtr_lft = 0, .accept_ra_pinfo =1 , #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1,
@@ -268,6 +269,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, + .accept_ra_min_rtr_lft = 0, .accept_ra_pinfo =1 , #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1,
@@ -6782,6 +6784,13 @@ static const struct ctl_table addrconf_sysctl[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "accept_ra_min_rtr_lft", + .data = &ipv6_devconf.accept_ra_min_rtr_lft, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, { .procname = "accept_ra_pinfo", .data = &ipv6_devconf.accept_ra_pinfo,
net/ipv6/ndisc.c +16 -2
@@ -1223,6 +1223,8 @@ static void ndisc_router_discovery(struct sk_buff *skb)return ; } + lifetime =ntohs (ra_msg->icmph.icmp6_rt_lifetime); +if (!ipv6_accept_ra (in6_dev)) { ND_PRINTK(2, info, "RA: %s, did not accept ra for dev: %s\n",
@@ -1230,6 +1232,13 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto skip_linkparms; } +if (lifetime !=0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { +ND_PRINTK (2 , info, +"RA: router lifetime (%ds) is too short: %s\n" , + lifetime, skb->dev->name); + goto skip_linkparms; + } +#ifdef CONFIG_IPV6_NDISC_NODETYPE /* skip link-specific parameters from interior routers */ if (skb->ndisc_nodetype ==NDISC_NODETYPE_NODEFAULT ) {
@@ -1282,8 +1291,6 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto skip_defrtr; } - lifetime =ntohs (ra_msg->icmph.icmp6_rt_lifetime); -#ifdef CONFIG_IPV6_ROUTER_PREF pref = ra_msg->icmph.icmp6_router_pref;/* 10b is handled as if it were 00b (medium) */
@@ -1430,6 +1437,13 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto out; } +if (lifetime !=0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { +ND_PRINTK (2 , info, +"RA: router lifetime (%ds) is too short: %s\n" , + lifetime, skb->dev->name); + goto out; + } +#ifdef CONFIG_IPV6_ROUTE_INFO if (!in6_dev->cnf.accept_ra_from_local && ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
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2.42.0.655.g421f12c284-goog
PATCH 2/3 net: change accept_ra_min_rtr_lft to affect all RA lifetimes
In reply to Patrick Rohrcommit 5027d54a9c30bc7ec808360378e2b4753f053f25 upstream.
(Backported without unnecessary UAPI portion.)
accept_ra_min_rtr_lft only considered the lifetime of the default route and discarded entire RAs accordingly.
This change renames accept_ra_min_rtr_lft to accept_ra_min_lft, and applies the value to individual RA sections; in particular, router lifetime, PIO preferred lifetime, and RIO lifetime. If any of those lifetimes are lower than the configured value, the specific RA section is ignored.
In order for the sysctl to be useful to Android, it should really apply to all lifetimes in the RA, since that is what determines the minimum frequency at which RAs must be processed by the kernel. Android uses hardware offloads to drop RAs for a fraction of the minimum of all lifetimes present in the RA (some networks have very frequent RAs (5s) with high lifetimes (2h)). Despite this, we have encountered networks that set the router lifetime to 30s which results in very frequent CPU wakeups. Instead of disabling IPv6 (and dropping IPv6 ethertype in the WiFi firmware) entirely on such networks, it seems better to ignore the misconfigured routers while still processing RAs from other IPv6 routers on the same network (i.e. to support IoT applications).
The previous implementation dropped the entire RA based on router lifetime. This turned out to be hard to expand to the other lifetimes present in the RA in a consistent manner; dropping the entire RA based on RIO/PIO lifetimes would essentially require parsing the whole thing twice.
--- Documentation/networking/ip-sysctl.rst | 8 ++++---- include/linux/ipv6.h | 2 +- net/ipv6/addrconf.c | 11 +++++++---- net/ipv6/ndisc.c | 27 +++++++++++--------------- 4 files changed, 23 insertions(+), 25 deletions(-)
Documentation/networking/ip-sysctl.rst +4 -4
@@ -2070,11 +2070,11 @@ accept_ra_min_hop_limit - INTEGER Default: 1 -accept_ra_min_rtr_lft - INTEGER - Minimum acceptable router lifetime in Router Advertisement. +accept_ra_min_lft - INTEGER + Minimum acceptable lifetime value in Router Advertisement. - RAs with a router lifetime less than this value shall be - ignored. RAs with a router lifetime of 0 are unaffected. + RA sections with a lifetime less than this value shall be + ignored. Zero lifetimes stay unaffected. Default: 0
include/linux/ipv6.h +1 -1
@@ -33,7 +33,7 @@ struct ipv6_devconf {__s32 accept_ra_defrtr;__u32 ra_defrtr_metric;__s32 accept_ra_min_hop_limit; -__s32 accept_ra_min_rtr_lft; +__s32 accept_ra_min_lft;__s32 accept_ra_pinfo;__s32 ignore_routes_with_linkdown;#ifdef CONFIG_IPV6_ROUTER_PREF
net/ipv6/addrconf.c +7 -4
@@ -209,7 +209,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, - .accept_ra_min_rtr_lft = 0, + .accept_ra_min_lft = 0, .accept_ra_pinfo =1 , #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1,
@@ -269,7 +269,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, - .accept_ra_min_rtr_lft = 0, + .accept_ra_min_lft = 0, .accept_ra_pinfo =1 , #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1,
@@ -2736,6 +2736,9 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)return ; } +if (valid_lft !=0 && valid_lft < in6_dev->cnf.accept_ra_min_lft) +return ; +/* * Two things going on here: * 1) Add routes for on-link prefixes
@@ -6785,8 +6788,8 @@ static const struct ctl_table addrconf_sysctl[] = { .proc_handler = proc_dointvec, }, { - .procname = "accept_ra_min_rtr_lft", - .data = &ipv6_devconf.accept_ra_min_rtr_lft, + .procname = "accept_ra_min_lft", + .data = &ipv6_devconf.accept_ra_min_lft, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec,
net/ipv6/ndisc.c +11 -16
@@ -1223,8 +1223,6 @@ static void ndisc_router_discovery(struct sk_buff *skb)return ; } - lifetime =ntohs (ra_msg->icmph.icmp6_rt_lifetime); -if (!ipv6_accept_ra (in6_dev)) { ND_PRINTK(2, info, "RA: %s, did not accept ra for dev: %s\n",
@@ -1232,13 +1230,6 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto skip_linkparms; } -if (lifetime !=0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { -ND_PRINTK (2 , info, -"RA: router lifetime (%ds) is too short: %s\n" , - lifetime, skb->dev->name); - goto skip_linkparms; - } -#ifdef CONFIG_IPV6_NDISC_NODETYPE /* skip link-specific parameters from interior routers */ if (skb->ndisc_nodetype ==NDISC_NODETYPE_NODEFAULT ) {
@@ -1279,6 +1270,14 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto skip_defrtr; } + lifetime =ntohs (ra_msg->icmph.icmp6_rt_lifetime); +if (lifetime !=0 && lifetime < in6_dev->cnf.accept_ra_min_lft) { +ND_PRINTK (2 , info, +"RA: router lifetime (%ds) is too short: %s\n" , + lifetime, skb->dev->name); + goto skip_defrtr; + } +/* Do not accept RA with source-addr found on local machine unless * accept_ra_from_local is set to true. */
@@ -1437,13 +1436,6 @@ static void ndisc_router_discovery(struct sk_buff *skb) goto out; } -if (lifetime !=0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { -ND_PRINTK (2 , info, -"RA: router lifetime (%ds) is too short: %s\n" , - lifetime, skb->dev->name); - goto out; - } -#ifdef CONFIG_IPV6_ROUTE_INFO if (!in6_dev->cnf.accept_ra_from_local && ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
@@ -1468,6 +1460,9 @@ static void ndisc_router_discovery(struct sk_buff *skb)if (ri->prefix_len ==0 && !in6_dev->cnf.accept_ra_defrtr)continue ; +if (ri->lifetime !=0 && +ntohl (ri->lifetime) < in6_dev->cnf.accept_ra_min_lft) +continue ;if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)continue ;if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
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2.42.0.655.g421f12c284-goog
David Ahern
maintainerRe: [PATCH 2/3] net: change accept_ra_min_rtr_lft to affect all RA lifetimes
Quoted 4 lines · Patrick Rohr
commit
5027d54a9c30bc7ec808360378e2b4753f053f25upstream.(Backported without unnecessary UAPI portion.)
no such thing as "unnecessary UAPI". If the original patch has a uapi, the backport to stable should have it too.
Re: [PATCH 2/3] net: change accept_ra_min_rtr_lft to affect all RA lifetimes
Quoted 10 lines · David Ahern
Quoted 4 lines · Patrick Rohr
commit
5027d54a9c30bc7ec808360378e2b4753f053f25upstream.(Backported without unnecessary UAPI portion.)
no such thing as "unnecessary UAPI". If the original patch has a uapi, the backport to stable should have it too.
Thanks for the guidance, David. I will follow up with a v2.
PATCH 3/3 net: release reference to inet6_dev pointer
In reply to Patrick Rohrcommit 5cb249686e67dbef3ffe53887fa725eefc5a7144 upstream.
addrconf_prefix_rcv returned early without releasing the inet6_dev pointer when the PIO lifetime is less than accept_ra_min_lft.
--- net/ipv6/addrconf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
net/ipv6/addrconf.c +1 -1
@@ -2737,7 +2737,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao) }if (valid_lft !=0 && valid_lft < in6_dev->cnf.accept_ra_min_lft) -return ; + goto put;/* * Two things going on here:
Signature · 1 line
2.42.0.655.g421f12c284-goog