From: Maciej Żenczykowski <m...@google.com> This implements: https://tools.ietf.org/html/rfc7559
Backoff is performed according to RFC3315 section 14: https://tools.ietf.org/html/rfc3315#section-14 Signed-off-by: Maciej Żenczykowski <m...@google.com> --- include/net/if_inet6.h | 1 + net/ipv6/addrconf.c | 34 ++++++++++++++++++++++++++++++---- 2 files changed, 31 insertions(+), 4 deletions(-) diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index 1c8b6820b694..515352c6280a 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -201,6 +201,7 @@ struct inet6_dev { struct ipv6_devstat stats; struct timer_list rs_timer; + __s32 rs_interval; /* in jiffies */ __u8 rs_probes; __u8 addr_gen_mode; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 84c46950876a..dc287f57c39b 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -112,6 +112,27 @@ static inline u32 cstamp_delta(unsigned long cstamp) return (cstamp - INITIAL_JIFFIES) * 100UL / HZ; } +static inline s32 rfc3315_s14_backoff_init(s32 irt) +{ + /* multiply 'initial retransmission time' by 0.9 .. 1.1 */ + u64 tmp = (900000 + prandom_u32() % 200001) * (u64)irt; + do_div(tmp, 1000000); + return (s32)tmp; +} + +static inline s32 rfc3315_s14_backoff_update(s32 rt, s32 mrt) +{ + /* multiply 'retransmission timeout' by 1.9 .. 2.1 */ + u64 tmp = (1900000 + prandom_u32() % 200001) * (u64)rt; + do_div(tmp, 1000000); + if ((s32)tmp > mrt) { + /* multiply 'maximum retransmission time' by 0.9 .. 1.1 */ + tmp = (900000 + prandom_u32() % 200001) * (u64)mrt; + do_div(tmp, 1000000); + } + return (s32)tmp; +} + #ifdef CONFIG_SYSCTL static int addrconf_sysctl_register(struct inet6_dev *idev); static void addrconf_sysctl_unregister(struct inet6_dev *idev); @@ -3698,11 +3719,13 @@ static void addrconf_rs_timer(unsigned long data) goto put; write_lock(&idev->lock); + idev->rs_interval = rfc3315_s14_backoff_update( + idev->rs_interval, idev->cnf.rtr_solicit_max_interval); /* The wait after the last probe can be shorter */ addrconf_mod_rs_timer(idev, (idev->rs_probes == idev->cnf.rtr_solicits) ? idev->cnf.rtr_solicit_delay : - idev->cnf.rtr_solicit_interval); + idev->rs_interval); } else { /* * Note: we do not support deprecated "all on-link" @@ -3973,10 +3996,11 @@ static void addrconf_dad_completed(struct inet6_ifaddr *ifp) write_lock_bh(&ifp->idev->lock); spin_lock(&ifp->lock); + ifp->idev->rs_interval = rfc3315_s14_backoff_init( + ifp->idev->cnf.rtr_solicit_interval); ifp->idev->rs_probes = 1; ifp->idev->if_flags |= IF_RS_SENT; - addrconf_mod_rs_timer(ifp->idev, - ifp->idev->cnf.rtr_solicit_interval); + addrconf_mod_rs_timer(ifp->idev, ifp->idev->rs_interval); spin_unlock(&ifp->lock); write_unlock_bh(&ifp->idev->lock); } @@ -5132,8 +5156,10 @@ update_lft: if (update_rs) { idev->if_flags |= IF_RS_SENT; + idev->rs_interval = rfc3315_s14_backoff_init( + idev->cnf.rtr_solicit_interval); idev->rs_probes = 1; - addrconf_mod_rs_timer(idev, idev->cnf.rtr_solicit_interval); + addrconf_mod_rs_timer(idev, idev->rs_interval); } /* Well, that's kinda nasty ... */ -- 2.8.0.rc3.226.g39d4020
