From 761aac737eb11901c382a3f021dead59a26983fc Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Wed, 15 Jan 2014 15:36:58 +0100 Subject: ipv6 addrconf: add IFA_F_NOPREFIXROUTE flag to suppress creation of IP6 routes When adding/modifying an IPv6 address, the userspace application needs a way to suppress adding a prefix route. This is for example relevant together with IFA_F_MANAGERTEMPADDR, where userspace creates autoconf generated addresses, but depending on on-link, no route for the prefix should be added. Signed-off-by: Thomas Haller Signed-off-by: David S. Miller --- include/uapi/linux/if_addr.h | 1 + net/ipv6/addrconf.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/uapi/linux/if_addr.h b/include/uapi/linux/if_addr.h index cfed10be7529..dea10a87dfd1 100644 --- a/include/uapi/linux/if_addr.h +++ b/include/uapi/linux/if_addr.h @@ -49,6 +49,7 @@ enum { #define IFA_F_TENTATIVE 0x40 #define IFA_F_PERMANENT 0x80 #define IFA_F_MANAGETEMPADDR 0x100 +#define IFA_F_NOPREFIXROUTE 0x200 struct ifa_cacheinfo { __u32 ifa_prefered; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 1b2e4ee3ce5e..85100c1ac761 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2434,8 +2434,11 @@ static int inet6_addr_add(struct net *net, int ifindex, valid_lft, prefered_lft); if (!IS_ERR(ifp)) { - addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev, - expires, flags); + if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) { + addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev, + expires, flags); + } + /* * Note that section 3.1 of RFC 4429 indicates * that the Optimistic flag should not be set for @@ -3662,7 +3665,8 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, spin_lock_bh(&ifp->lock); was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR; ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | - IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR); + IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR | + IFA_F_NOPREFIXROUTE); ifp->flags |= ifa_flags; ifp->tstamp = jiffies; ifp->valid_lft = valid_lft; @@ -3672,8 +3676,10 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, if (!(ifp->flags&IFA_F_TENTATIVE)) ipv6_ifa_notify(0, ifp); - addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev, - expires, flags); + if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) { + addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev, + expires, flags); + } if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) { if (was_managetempaddr && !(ifp->flags & IFA_F_MANAGETEMPADDR)) @@ -3727,7 +3733,8 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh) ifa_flags = tb[IFA_FLAGS] ? nla_get_u32(tb[IFA_FLAGS]) : ifm->ifa_flags; /* We ignore other flags so far. */ - ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR; + ifa_flags &= IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR | + IFA_F_NOPREFIXROUTE; ifa = ipv6_get_ifaddr(net, pfx, dev, 1); if (ifa == NULL) { -- cgit v1.2.3 From 5b84efecb7d939d06790b7bace5e513537d0767c Mon Sep 17 00:00:00 2001 From: Thomas Haller Date: Wed, 15 Jan 2014 15:36:59 +0100 Subject: ipv6 addrconf: don't cleanup prefix route for IFA_F_NOPREFIXROUTE Refactor the deletion/update of prefix routes when removing an address. Now also consider IFA_F_NOPREFIXROUTE and if there is an address present with this flag, to not cleanup the route. Instead, assume that userspace is taking care of this route. Also perform the same cleanup, when userspace changes an existing address to add NOPREFIXROUTE (to an address that didn't have this flag). This is done because when the address was added, a prefix route was created for it. Since the user now wants to handle this route by himself, we cleanup this route. This cleanup of the route is not totally robust. There is no guarantee, that the route we are about to delete was really the one added by the kernel. This behavior does not change by the patch, and in practice it should work just fine. Signed-off-by: Thomas Haller Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 184 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 109 insertions(+), 75 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 85100c1ac761..6913a82f4669 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -900,15 +900,95 @@ out: goto out2; } +enum cleanup_prefix_rt_t { + CLEANUP_PREFIX_RT_NOP, /* no cleanup action for prefix route */ + CLEANUP_PREFIX_RT_DEL, /* delete the prefix route */ + CLEANUP_PREFIX_RT_EXPIRE, /* update the lifetime of the prefix route */ +}; + +/* + * Check, whether the prefix for ifp would still need a prefix route + * after deleting ifp. The function returns one of the CLEANUP_PREFIX_RT_* + * constants. + * + * 1) we don't purge prefix if address was not permanent. + * prefix is managed by its own lifetime. + * 2) we also don't purge, if the address was IFA_F_NOPREFIXROUTE. + * 3) if there are no addresses, delete prefix. + * 4) if there are still other permanent address(es), + * corresponding prefix is still permanent. + * 5) if there are still other addresses with IFA_F_NOPREFIXROUTE, + * don't purge the prefix, assume user space is managing it. + * 6) otherwise, update prefix lifetime to the + * longest valid lifetime among the corresponding + * addresses on the device. + * Note: subsequent RA will update lifetime. + **/ +static enum cleanup_prefix_rt_t +check_cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long *expires) +{ + struct inet6_ifaddr *ifa; + struct inet6_dev *idev = ifp->idev; + unsigned long lifetime; + enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_DEL; + + *expires = jiffies; + + list_for_each_entry(ifa, &idev->addr_list, if_list) { + if (ifa == ifp) + continue; + if (!ipv6_prefix_equal(&ifa->addr, &ifp->addr, + ifp->prefix_len)) + continue; + if (ifa->flags & (IFA_F_PERMANENT | IFA_F_NOPREFIXROUTE)) + return CLEANUP_PREFIX_RT_NOP; + + action = CLEANUP_PREFIX_RT_EXPIRE; + + spin_lock(&ifa->lock); + + lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ); + /* + * Note: Because this address is + * not permanent, lifetime < + * LONG_MAX / HZ here. + */ + if (time_before(*expires, ifa->tstamp + lifetime * HZ)) + *expires = ifa->tstamp + lifetime * HZ; + spin_unlock(&ifa->lock); + } + + return action; +} + +static void +cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, bool del_rt) +{ + struct rt6_info *rt; + + rt = addrconf_get_prefix_route(&ifp->addr, + ifp->prefix_len, + ifp->idev->dev, + 0, RTF_GATEWAY | RTF_DEFAULT); + if (rt) { + if (del_rt) + ip6_del_rt(rt); + else { + if (!(rt->rt6i_flags & RTF_EXPIRES)) + rt6_set_expires(rt, expires); + ip6_rt_put(rt); + } + } +} + + /* This function wants to get referenced ifp and releases it before return */ static void ipv6_del_addr(struct inet6_ifaddr *ifp) { - struct inet6_ifaddr *ifa, *ifn; - struct inet6_dev *idev = ifp->idev; int state; - int deleted = 0, onlink = 0; - unsigned long expires = jiffies; + enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP; + unsigned long expires; spin_lock_bh(&ifp->state_lock); state = ifp->state; @@ -922,7 +1002,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) hlist_del_init_rcu(&ifp->addr_lst); spin_unlock_bh(&addrconf_hash_lock); - write_lock_bh(&idev->lock); + write_lock_bh(&ifp->idev->lock); if (ifp->flags&IFA_F_TEMPORARY) { list_del(&ifp->tmp_list); @@ -933,45 +1013,13 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) __in6_ifa_put(ifp); } - list_for_each_entry_safe(ifa, ifn, &idev->addr_list, if_list) { - if (ifa == ifp) { - list_del_init(&ifp->if_list); - __in6_ifa_put(ifp); + if (ifp->flags & IFA_F_PERMANENT && !(ifp->flags & IFA_F_NOPREFIXROUTE)) + action = check_cleanup_prefix_route(ifp, &expires); - if (!(ifp->flags & IFA_F_PERMANENT) || onlink > 0) - break; - deleted = 1; - continue; - } else if (ifp->flags & IFA_F_PERMANENT) { - if (ipv6_prefix_equal(&ifa->addr, &ifp->addr, - ifp->prefix_len)) { - if (ifa->flags & IFA_F_PERMANENT) { - onlink = 1; - if (deleted) - break; - } else { - unsigned long lifetime; - - if (!onlink) - onlink = -1; - - spin_lock(&ifa->lock); - - lifetime = addrconf_timeout_fixup(ifa->valid_lft, HZ); - /* - * Note: Because this address is - * not permanent, lifetime < - * LONG_MAX / HZ here. - */ - if (time_before(expires, - ifa->tstamp + lifetime * HZ)) - expires = ifa->tstamp + lifetime * HZ; - spin_unlock(&ifa->lock); - } - } - } - } - write_unlock_bh(&idev->lock); + list_del_init(&ifp->if_list); + __in6_ifa_put(ifp); + + write_unlock_bh(&ifp->idev->lock); addrconf_del_dad_timer(ifp); @@ -979,38 +1027,9 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) inet6addr_notifier_call_chain(NETDEV_DOWN, ifp); - /* - * Purge or update corresponding prefix - * - * 1) we don't purge prefix here if address was not permanent. - * prefix is managed by its own lifetime. - * 2) if there are no addresses, delete prefix. - * 3) if there are still other permanent address(es), - * corresponding prefix is still permanent. - * 4) otherwise, update prefix lifetime to the - * longest valid lifetime among the corresponding - * addresses on the device. - * Note: subsequent RA will update lifetime. - * - * --yoshfuji - */ - if ((ifp->flags & IFA_F_PERMANENT) && onlink < 1) { - struct rt6_info *rt; - - rt = addrconf_get_prefix_route(&ifp->addr, - ifp->prefix_len, - ifp->idev->dev, - 0, RTF_GATEWAY | RTF_DEFAULT); - - if (rt) { - if (onlink == 0) { - ip6_del_rt(rt); - rt = NULL; - } else if (!(rt->rt6i_flags & RTF_EXPIRES)) { - rt6_set_expires(rt, expires); - } - } - ip6_rt_put(rt); + if (action != CLEANUP_PREFIX_RT_NOP) { + cleanup_prefix_route(ifp, expires, + action == CLEANUP_PREFIX_RT_DEL); } /* clean up prefsrc entries */ @@ -3636,6 +3655,7 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, clock_t expires; unsigned long timeout; bool was_managetempaddr; + bool had_prefixroute; if (!valid_lft || (prefered_lft > valid_lft)) return -EINVAL; @@ -3664,6 +3684,8 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, spin_lock_bh(&ifp->lock); was_managetempaddr = ifp->flags & IFA_F_MANAGETEMPADDR; + had_prefixroute = ifp->flags & IFA_F_PERMANENT && + !(ifp->flags & IFA_F_NOPREFIXROUTE); ifp->flags &= ~(IFA_F_DEPRECATED | IFA_F_PERMANENT | IFA_F_NODAD | IFA_F_HOMEADDRESS | IFA_F_MANAGETEMPADDR | IFA_F_NOPREFIXROUTE); @@ -3679,6 +3701,18 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) { addrconf_prefix_route(&ifp->addr, ifp->prefix_len, ifp->idev->dev, expires, flags); + } else if (had_prefixroute) { + enum cleanup_prefix_rt_t action; + unsigned long rt_expires; + + write_lock_bh(&ifp->idev->lock); + action = check_cleanup_prefix_route(ifp, &rt_expires); + write_unlock_bh(&ifp->idev->lock); + + if (action != CLEANUP_PREFIX_RT_NOP) { + cleanup_prefix_route(ifp, rt_expires, + action == CLEANUP_PREFIX_RT_DEL); + } } if (was_managetempaddr || ifp->flags & IFA_F_MANAGETEMPADDR) { -- cgit v1.2.3