From 2d6c1375ba3035256364bee4fe56dbef6dc54d32 Mon Sep 17 00:00:00 2001 From: Patrick Rohr Date: Fri, 13 Oct 2023 14:44:13 -0700 Subject: [PATCH] BACKPORT: net: change accept_ra_min_rtr_lft to affect all RA lifetimes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 5027d54a9c30bc7ec808360378e2b4753f053f25 upstream. 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. Change-Id: I2168608875629ae07bbd30a02a061284110693e7 Fixes: 1671bcfd76fd ("net: add sysctl accept_ra_min_rtr_lft") Cc: Lorenzo Colitti Signed-off-by: Patrick Rohr Reviewed-by: Maciej Żenczykowski Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230726230701.919212-1-prohr@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- Documentation/networking/ip-sysctl.txt | 8 ++++---- include/linux/ipv6.h | 2 +- include/uapi/linux/ipv6.h | 2 +- net/ipv6/addrconf.c | 13 ++++++++----- net/ipv6/ndisc.c | 27 +++++++++++--------------- 5 files changed, 25 insertions(+), 27 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 4f48e6398975..11ad3403bdda 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1660,11 +1660,11 @@ 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 diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index fbdbef37b4f4..6003273ec2e9 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -33,7 +33,7 @@ struct ipv6_devconf { __s32 max_addresses; __s32 accept_ra_defrtr; __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 diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 79c11618a6b7..45406a092e4e 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -187,7 +187,7 @@ enum { DEVCONF_DISABLE_POLICY, DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, DEVCONF_NDISC_TCLASS, - DEVCONF_ACCEPT_RA_MIN_RTR_LFT, + DEVCONF_ACCEPT_RA_MIN_LFT, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 0bd88451596c..051bbc0e7c74 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -208,7 +208,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_ra_defrtr = 1, .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, @@ -264,7 +264,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .accept_ra_defrtr = 1, .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, @@ -2751,6 +2751,9 @@ 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 @@ -5549,7 +5552,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_ADDR_GEN_MODE] = cnf->addr_gen_mode; array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy; array[DEVCONF_NDISC_TCLASS] = cnf->ndisc_tclass; - array[DEVCONF_ACCEPT_RA_MIN_RTR_LFT] = cnf->accept_ra_min_rtr_lft; + array[DEVCONF_ACCEPT_RA_MIN_LFT] = cnf->accept_ra_min_lft; } static inline size_t inet6_ifla6_size(void) @@ -6718,8 +6721,8 @@ 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, diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 2b170586da01..653e5bc7f047 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1224,8 +1224,6 @@ 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", @@ -1233,13 +1231,6 @@ 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) { @@ -1280,6 +1271,14 @@ 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. */ @@ -1438,13 +1437,6 @@ skip_linkparms: 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, @@ -1469,6 +1461,9 @@ skip_linkparms: 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)