[net-next,v2] ipv6: fix multipath route replace error recovery

Message ID	1441237466-22302-1-git-send-email-roopa@cumulusnetworks.com
State	Changes Requested, archived
Delegated to:	David Miller
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: Roopa Prabhu <roopa@cumulusnetworks.com> To: davem@davemloft.net Cc: Mazziesaccount@gmail.com, hannes@stressinduktion.org, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org Subject: [PATCH net-next v2] ipv6: fix multipath route replace error recovery Date: Wed, 2 Sep 2015 16:44:26 -0700 Message-Id: <1441237466-22302-1-git-send-email-roopa@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk

diff --git a/net/ipv6/route.c b/net/ipv6/route.c index f45cac6..ecbb974 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1748,7 +1748,7 @@ static int ip6_convert_metrics(struct mx6_config *mxc, return -EINVAL; } -int ip6_route_add(struct fib6_config *cfg) +int ip6_route_info_create(struct fib6_config *cfg, struct rt6_info **rt_ret) { int err; struct net *net = cfg->fc_nlinfo.nl_net; @@ -1756,7 +1756,6 @@ int ip6_route_add(struct fib6_config *cfg) struct net_device *dev = NULL; struct inet6_dev *idev = NULL; struct fib6_table *table; - struct mx6_config mxc = { .mx = NULL, }; int addr_type; if (cfg->fc_dst_len > 128 || cfg->fc_src_len > 128) @@ -1981,6 +1980,32 @@ install_route: cfg->fc_nlinfo.nl_net = dev_net(dev); + *rt_ret = rt; + + return 0; +out: + if (dev) + dev_put(dev); + if (idev) + in6_dev_put(idev); + if (rt) + dst_free(&rt->dst); + + *rt_ret = NULL; + + return err; +} + +int ip6_route_add(struct fib6_config *cfg) +{ + struct mx6_config mxc = { .mx = NULL, }; + struct rt6_info *rt = NULL; + int err; + + err = ip6_route_info_create(cfg, &rt); + if (err) + goto out; + err = ip6_convert_metrics(&mxc, cfg); if (err) goto out; @@ -1988,14 +2013,12 @@ install_route: err = __ip6_ins_rt(rt, &cfg->fc_nlinfo, &mxc); kfree(mxc.mx); + return err; out: - if (dev) - dev_put(dev); - if (idev) - in6_dev_put(idev); if (rt) dst_free(&rt->dst); + return err; } @@ -2776,19 +2799,79 @@ errout: return err; } -static int ip6_route_multipath(struct fib6_config *cfg, int add) +struct rt6_nh { + struct rt6_info *rt6_info; + struct fib6_config r_cfg; + struct mx6_config mxc; + struct list_head next; +}; + +static void ip6_print_replace_route_err(struct list_head *rt6_nh_list) +{ + struct rt6_nh *nh; + char *errstr = "IPV6: unexpected error replacing route"; + + list_for_each_entry(nh, rt6_nh_list, next) { + printk(KERN_WARNING "%s: %pI6 nexthop %pI6 ifi %d\n", + errstr, &nh->r_cfg.fc_dst, &nh->r_cfg.fc_gateway, + nh->r_cfg.fc_ifindex); + } +} + +static int ip6_route_info_append(struct list_head *rt6_nh_list, + struct rt6_info *rt, struct fib6_config *r_cfg) +{ + struct rt6_nh *nh; + struct rt6_info *rtnh; + int err = -EEXIST; + + list_for_each_entry(nh, rt6_nh_list, next) { + /* check if rt6_info already exists */ + rtnh = nh->rt6_info; + + if (rtnh->dst.dev == rt->dst.dev && + rtnh->rt6i_idev == rt->rt6i_idev && + ipv6_addr_equal(&rtnh->rt6i_gateway, + &rt->rt6i_gateway)) + return err; + } + + nh = kzalloc(sizeof(*nh), GFP_KERNEL); + if (!nh) + return -ENOMEM; + nh->rt6_info = rt; + err = ip6_convert_metrics(&nh->mxc, r_cfg); + if (err) { + kfree(nh); + return err; + } + memcpy(&nh->r_cfg, r_cfg, sizeof(*r_cfg)); + list_add_tail(&nh->next, rt6_nh_list); + + return 0; +} + +static int ip6_route_multipath_add(struct fib6_config *cfg) { struct fib6_config r_cfg; struct rtnexthop *rtnh; + struct rt6_info *rt; + struct rt6_nh *err_nh; + struct rt6_nh *nh, *nh_safe; int remaining; int attrlen; - int err = 0, last_err = 0; + int err = 1; + int nhn = 0; + int replace = (cfg->fc_nlinfo.nlh && + (cfg->fc_nlinfo.nlh->nlmsg_flags & NLM_F_REPLACE)); + LIST_HEAD(rt6_nh_list); remaining = cfg->fc_mp_len; -beginning: rtnh = (struct rtnexthop *)cfg->fc_mp; - /* Parse a Multipath Entry */ + /* Parse a Multipath Entry and build a list (rt6_nh_list) of + * rt6_info structs per nexthop + */ while (rtnh_ok(rtnh, remaining)) { memcpy(&r_cfg, cfg, sizeof(*cfg)); if (rtnh->rtnh_ifindex) @@ -2808,22 +2891,34 @@ beginning: if (nla) r_cfg.fc_encap_type = nla_get_u16(nla); } - err = add ? ip6_route_add(&r_cfg) : ip6_route_del(&r_cfg); + + err = ip6_route_info_create(&r_cfg, &rt); + if (err) + goto cleanup; + + err = ip6_route_info_append(&rt6_nh_list, rt, &r_cfg); if (err) { - last_err = err; - /* If we are trying to remove a route, do not stop the - * loop when ip6_route_del() fails (because next hop is - * already gone), we should try to remove all next hops. - */ - if (add) { - /* If add fails, we should try to delete all - * next hops that have been already added. - */ - add = 0; - remaining = cfg->fc_mp_len - remaining; - goto beginning; - } + if (rt->rt6i_idev) + in6_dev_put(rt->rt6i_idev); + dst_free(&rt->dst); + goto cleanup; + } + + rtnh = rtnh_next(rtnh, &remaining); + } + + err_nh = NULL; + list_for_each_entry(nh, &rt6_nh_list, next) { + err = __ip6_ins_rt(nh->rt6_info, &cfg->fc_nlinfo, &nh->mxc); + /* nh->rt6_info is used or freed at this point, reset to NULL*/ + nh->rt6_info = NULL; + if (err) { + if (replace && nhn) + ip6_print_replace_route_err(&rt6_nh_list); + err_nh = nh; + goto add_errout; } + /* Because each route is added like a single route we remove * these flags after the first nexthop: if there is a collision, * we have already failed to add the first nexthop: @@ -2833,6 +2928,68 @@ beginning: */ cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | NLM_F_REPLACE); + nhn++; + } + + goto cleanup; + +add_errout: + /* Delete routes that were already added */ + list_for_each_entry(nh, &rt6_nh_list, next) { + if (err_nh == nh) + break; + ip6_route_del(&nh->r_cfg); + } + +cleanup: + list_for_each_entry_safe(nh, nh_safe, &rt6_nh_list, next) { + if (nh->rt6_info) { + struct rt6_info *r = nh->rt6_info; + + if (r->rt6i_idev) + in6_dev_put(r->rt6i_idev); + dst_free(&r->dst); + } + if (nh->mxc.mx) + kfree(nh->mxc.mx); + list_del(&nh->next); + kfree(nh); + } + + return err; +} + +static int ip6_route_multipath_del(struct fib6_config *cfg) +{ + struct fib6_config r_cfg; + struct rtnexthop *rtnh; + int remaining; + int attrlen; + int err = 1, last_err = 0; + + remaining = cfg->fc_mp_len; + rtnh = (struct rtnexthop *)cfg->fc_mp; + + /* Parse a Multipath Entry */ + while (rtnh_ok(rtnh, remaining)) { + memcpy(&r_cfg, cfg, sizeof(*cfg)); + if (rtnh->rtnh_ifindex) + r_cfg.fc_ifindex = rtnh->rtnh_ifindex; + + attrlen = rtnh_attrlen(rtnh); + if (attrlen > 0) { + struct nlattr *nla, *attrs = rtnh_attrs(rtnh); + + nla = nla_find(attrs, attrlen, RTA_GATEWAY); + if (nla) { + nla_memcpy(&r_cfg.fc_gateway, nla, 16); + r_cfg.fc_flags |= RTF_GATEWAY; + } + } + err = ip6_route_del(&r_cfg); + if (err) + last_err = err; + rtnh = rtnh_next(rtnh, &remaining); } @@ -2849,7 +3006,7 @@ static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh) return err; if (cfg.fc_mp) - return ip6_route_multipath(&cfg, 0); + return ip6_route_multipath_del(&cfg); else return ip6_route_del(&cfg); } @@ -2864,7 +3021,7 @@ static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh) return err; if (cfg.fc_mp) - return ip6_route_multipath(&cfg, 1); + return ip6_route_multipath_add(&cfg); else return ip6_route_add(&cfg); }

[net-next,v2] ipv6: fix multipath route replace error recovery

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