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Date: Wed, 30 Dec 2020 00:48:33 -0800 Message-Id: <1609318113-12770-2-git-send-email-pchaudhary@linkedin.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1609318113-12770-1-git-send-email-pchaudhary@linkedin.com> References: <1609318113-12770-1-git-send-email-pchaudhary@linkedin.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Fix: 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 Signed-off-by: Zhenggen Xu --- Documentation/networking/ip-sysctl.rst | 8 ++++++++ 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 | 10 ++++++++++ net/ipv6/ndisc.c | 15 +++++++++++---- net/ipv6/route.c | 8 +++++--- 8 files changed, 39 insertions(+), 8 deletions(-) diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index dd2b12a..073c1f3 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1871,6 +1871,14 @@ accept_ra_defrtr - BOOLEAN - enabled if accept_ra is enabled. - disabled if accept_ra is disabled. +accept_ra_defrtr_metric - INTEGER + Metric for default router learned in Router Advertisement. + + Functional default: + + * 0 if accept_ra_defrtr is enabled. + * Ignored, if accept_ra_defrtr is enabled. + 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 dda61d1..19af90c 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; + __s32 accept_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 2a52777..a470bda 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, + unsigned int 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 13e8751..945de5d 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_ACCEPT_RA_DEFRTR_METRIC, DEVCONF_MAX }; diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 458179d..5e79c19 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_ACCEPT_RA_DEFRTR_METRIC=28, __NET_IPV6_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index eff2cac..702ec4a 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, + .accept_ra_defrtr_metric = 0, .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, + .accept_ra_defrtr_metric = 0, .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_ACCEPT_RA_DEFRTR_METRIC] = cnf->accept_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 @@ -6668,6 +6671,13 @@ static const struct ctl_table addrconf_sysctl[] = { .proc_handler = proc_dointvec, }, { + .procname = "accept_ra_defrtr_metric", + .data = &ipv6_devconf.accept_ra_defrtr_metric, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { .procname = "accept_ra_min_hop_limit", .data = &ipv6_devconf.accept_ra_min_hop_limit, .maxlen = sizeof(int), diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 7671747..05f7f24 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1180,6 +1180,7 @@ static void ndisc_router_discovery(struct sk_buff *skb) unsigned int pref = 0; __u32 old_if_flags; bool send_ifinfo_notify = false; + unsigned int defrtr_usr_metric = 0; __u8 *opt = (__u8 *)(ra_msg + 1); @@ -1303,18 +1304,24 @@ static void ndisc_router_discovery(struct sk_buff *skb) return; } } - if (rt && lifetime == 0) { + + defrtr_usr_metric = in6_dev->cnf.accept_ra_defrtr_metric; + /* default metric is IP6_RT_PRIO_USER */ + if (defrtr_usr_metric == 0) + defrtr_usr_metric = IP6_RT_PRIO_USER; + /* delete the route if lifetime is 0 or if new metric is needed */ + if (rt && (lifetime == 0 || rt->rt6i_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 188e114..249b211 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, + unsigned int 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 ? defrtr_usr_metric : IP6_RT_PRIO_USER, .fc_ifindex = dev->ifindex, .fc_flags = RTF_GATEWAY | RTF_ADDRCONF | RTF_DEFAULT | RTF_UP | RTF_EXPIRES | RTF_PREF(pref), @@ -4266,7 +4267,8 @@ struct fib6_info *rt6_add_dflt_router(struct net *net, .fc_nlinfo.nlh = NULL, .fc_nlinfo.nl_net = net, }; - + ND_PRINTK(3, info, "RA: metric: %d for dev: %s\n", + cfg.fc_metric, dev->name); cfg.fc_gateway = *gwaddr; if (!ip6_route_add(&cfg, GFP_ATOMIC, NULL)) { -- 2.7.4