From a8c70a62b8c16364bcab5045d84fa5c355e755f8 Mon Sep 17 00:00:00 2001 From: Patrick Rohr Date: Fri, 13 Oct 2023 14:44:12 -0700 Subject: [PATCH] BACKPORT: net: add sysctl accept_ra_min_rtr_lft MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 1671bcfd76fdc0b9e65153cf759153083755fe4c upstream. 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. Change-Id: I5e575f2e2d303c6736fc5e983b65003c7e7a075a Signed-off-by: Patrick Rohr Cc: Maciej Żenczykowski Cc: Lorenzo Colitti Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- Documentation/networking/ip-sysctl.txt | 8 ++++++++ include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 10 ++++++++++ net/ipv6/ndisc.c | 18 ++++++++++++++++-- 5 files changed, 36 insertions(+), 2 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 12cf648120f4..4f48e6398975 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1660,6 +1660,14 @@ 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. diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 6f006ccbdca7..fbdbef37b4f4 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -33,6 +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_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 9c0f4a92bcff..79c11618a6b7 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -187,6 +187,7 @@ enum { DEVCONF_DISABLE_POLICY, DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, DEVCONF_NDISC_TCLASS, + DEVCONF_ACCEPT_RA_MIN_RTR_LFT, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 7b9ac231b654..0bd88451596c 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -208,6 +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_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -263,6 +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_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -5547,6 +5549,7 @@ 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; } static inline size_t inet6_ifla6_size(void) @@ -6714,6 +6717,13 @@ 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, diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index f6b5340c5e11..2b170586da01 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1224,6 +1224,8 @@ 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", @@ -1231,6 +1233,13 @@ 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) { @@ -1283,8 +1292,6 @@ 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) */ @@ -1431,6 +1438,13 @@ 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,