From 4cfe6dd10f382e0604149d3a507c1fca874f4095 Mon Sep 17 00:00:00 2001 From: Patrick Rohr Date: Fri, 13 Oct 2023 14:44:12 -0700 Subject: [PATCH] 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. 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.rst | 8 ++++++++ include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 7 +++++++ net/ipv6/addrconf.c | 10 ++++++++++ net/ipv6/ndisc.c | 18 ++++++++++++++++-- 5 files changed, 42 insertions(+), 2 deletions(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index eedce7474..8e6b2c031 100755 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1902,6 +1902,14 @@ 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 9a6832eb8..7471874b4 100755 --- 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 2aadbba4e..6a00ee398 100755 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -196,6 +196,13 @@ enum { DEVCONF_ACCEPT_RA_RT_INFO_MIN_PLEN, DEVCONF_NDISC_TCLASS, DEVCONF_RPL_SEG_ENABLED, + DEVCONF_RA_DEFRTR_METRIC, + DEVCONF_IOAM6_ENABLED, + DEVCONF_IOAM6_ID, + DEVCONF_IOAM6_ID_WIDE, + DEVCONF_NDISC_EVICT_NOCARRIER, + DEVCONF_ACCEPT_UNTRACKED_NA, + DEVCONF_ACCEPT_RA_MIN_RTR_LFT, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index fbd2adf52..6aa85427a 100755 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -209,6 +209,7 @@ 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, @@ -265,6 +266,7 @@ 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, @@ -5598,6 +5600,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy; array[DEVCONF_NDISC_TCLASS] = cnf->ndisc_tclass; array[DEVCONF_RPL_SEG_ENABLED] = cnf->rpl_seg_enabled; + array[DEVCONF_ACCEPT_RA_MIN_RTR_LFT] = cnf->accept_ra_min_rtr_lft; } static inline size_t inet6_ifla6_size(void) @@ -6755,6 +6758,13 @@ 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 ac1e51087..215ea5dbc 100755 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1222,6 +1222,8 @@ 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", @@ -1229,6 +1231,13 @@ 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) { @@ -1281,8 +1290,6 @@ 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) */ @@ -1429,6 +1436,13 @@ 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,