diff options
| -rw-r--r-- | include/net/if_inet6.h | 1 | ||||
| -rw-r--r-- | net/ipv6/addrconf.c | 39 |
2 files changed, 32 insertions, 8 deletions
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index ae707352f463..b0576cb2ab25 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -190,6 +190,7 @@ struct inet6_dev { __u32 if_flags; int dead; + u32 desync_factor; u8 rndid[8]; struct list_head tempaddr_list; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 58c3d73403a5..cc7c26d05f45 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -422,6 +422,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev) #endif INIT_LIST_HEAD(&ndev->tempaddr_list); + ndev->desync_factor = U32_MAX; if ((dev->flags&IFF_LOOPBACK) || dev->type == ARPHRD_TUNNEL || dev->type == ARPHRD_TUNNEL6 || @@ -1183,6 +1184,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *i int ret = 0; u32 addr_flags; unsigned long now = jiffies; + long max_desync_factor; write_lock_bh(&idev->lock); if (ift) { @@ -1218,20 +1220,41 @@ retry: ipv6_try_regen_rndid(idev, tmpaddr); memcpy(&addr.s6_addr[8], idev->rndid, 8); age = (now - ifp->tstamp) / HZ; + + regen_advance = idev->cnf.regen_max_retry * + idev->cnf.dad_transmits * + NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ; + + /* recalculate max_desync_factor each time and update + * idev->desync_factor if it's larger + */ + max_desync_factor = min_t(__u32, + idev->cnf.max_desync_factor, + idev->cnf.temp_prefered_lft - regen_advance); + + if (unlikely(idev->desync_factor > max_desync_factor)) { + if (max_desync_factor > 0) { + get_random_bytes(&idev->desync_factor, + sizeof(idev->desync_factor)); + idev->desync_factor %= max_desync_factor; + } else { + idev->desync_factor = 0; + } + } + tmp_valid_lft = min_t(__u32, ifp->valid_lft, idev->cnf.temp_valid_lft + age); - tmp_prefered_lft = min_t(__u32, - ifp->prefered_lft, - idev->cnf.temp_prefered_lft + age - - idev->cnf.max_desync_factor); + tmp_prefered_lft = idev->cnf.temp_prefered_lft + age - + idev->desync_factor; + /* guard against underflow in case of concurrent updates to cnf */ + if (unlikely(tmp_prefered_lft < 0)) + tmp_prefered_lft = 0; + tmp_prefered_lft = min_t(__u32, ifp->prefered_lft, tmp_prefered_lft); tmp_plen = ifp->prefix_len; tmp_tstamp = ifp->tstamp; spin_unlock_bh(&ifp->lock); - regen_advance = idev->cnf.regen_max_retry * - idev->cnf.dad_transmits * - NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ; write_unlock_bh(&idev->lock); /* A temporary address is created only if this calculated Preferred @@ -2316,7 +2339,7 @@ static void manage_tempaddrs(struct inet6_dev *idev, max_valid = 0; max_prefered = idev->cnf.temp_prefered_lft - - idev->cnf.max_desync_factor - age; + idev->desync_factor - age; if (max_prefered < 0) max_prefered = 0; |