From e1b11c518aded9136b4f44759c6e2a6be4161ee9 Mon Sep 17 00:00:00 2001 From: Steven Barth Date: Wed, 23 Oct 2013 10:13:00 +0200 Subject: [PATCH] Avoid updating too often if ISP spams RAs --- src/odhcp6c.c | 13 ++++++++++--- src/odhcp6c.h | 4 ++-- src/ra.c | 13 +++++++------ 3 files changed, 19 insertions(+), 11 deletions(-) diff --git a/src/odhcp6c.c b/src/odhcp6c.c index 5c433af..e81b15f 100644 --- a/src/odhcp6c.c +++ b/src/odhcp6c.c @@ -463,17 +463,23 @@ struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct } -void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe) +bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe) { size_t len; struct odhcp6c_entry *x = odhcp6c_find_entry(state, new); struct odhcp6c_entry *start = odhcp6c_get_state(state, &len); + bool changed = true; if (x && x->valid > new->valid && new->valid < safe) new->valid = safe; if (new->valid > 0) { if (x) { + if (new->valid >= x->valid && new->valid - x->valid < 60 && + new->preferred >= x->preferred && + new->preferred - x->preferred < 60 && + x->class == new->class) + changed = false; x->valid = new->valid; x->preferred = new->preferred; x->class = new->class; @@ -483,12 +489,13 @@ void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *n } else if (x) { odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x)); } + return changed; } -void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new) +bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new) { - odhcp6c_update_entry_safe(state, new, 0); + return odhcp6c_update_entry_safe(state, new, 0); } diff --git a/src/odhcp6c.h b/src/odhcp6c.h index 669b33d..61dee63 100644 --- a/src/odhcp6c.h +++ b/src/odhcp6c.h @@ -250,8 +250,8 @@ void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len); // Entry manipulation struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new); -void odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new); -void odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe); +bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new); +bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe); void odhcp6c_expire(void); uint32_t odhcp6c_elapsed(void); diff --git a/src/ra.c b/src/ra.c index 83f1758..f41602a 100644 --- a/src/ra.c +++ b/src/ra.c @@ -120,6 +120,7 @@ static void update_proc(const char *sect, const char *opt, uint32_t value) bool ra_process(void) { bool found = false; + bool changed = false; uint8_t buf[1500], cmsg_buf[128]; struct nd_router_advert *adv = (struct nd_router_advert*)buf; struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0}; @@ -183,7 +184,7 @@ bool ra_process(void) entry.priority = pref_to_priority(0); entry.valid = router_valid; entry.preferred = entry.valid; - odhcp6c_update_entry(STATE_RA_ROUTE, &entry); + changed |= odhcp6c_update_entry(STATE_RA_ROUTE, &entry); // Parse ND parameters if (ntohl(adv->nd_ra_reachable) <= 3600000) @@ -215,7 +216,7 @@ bool ra_process(void) continue; if (entry.priority > 0) - odhcp6c_update_entry(STATE_RA_ROUTE, &entry); + changed |= odhcp6c_update_entry(STATE_RA_ROUTE, &entry); } else if (opt->type == ND_OPT_PREFIX_INFORMATION && opt->len == 4) { struct nd_opt_prefix_info *pinfo = (struct nd_opt_prefix_info*)opt; entry.router = any; @@ -232,7 +233,7 @@ bool ra_process(void) continue; if (pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK) - odhcp6c_update_entry_safe(STATE_RA_ROUTE, &entry, 7200); + changed |= odhcp6c_update_entry_safe(STATE_RA_ROUTE, &entry, 7200); if (!(pinfo->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_AUTO) || pinfo->nd_opt_pi_prefix_len != 64) @@ -241,7 +242,7 @@ bool ra_process(void) entry.target.s6_addr32[2] = lladdr.s6_addr32[2]; entry.target.s6_addr32[3] = lladdr.s6_addr32[3]; - odhcp6c_update_entry_safe(STATE_RA_PREFIX, &entry, 7200); + changed |= odhcp6c_update_entry_safe(STATE_RA_PREFIX, &entry, 7200); } else if (opt->type == ND_OPT_RECURSIVE_DNS && opt->len > 2) { entry.router = from.sin6_addr; entry.priority = 0; @@ -253,7 +254,7 @@ bool ra_process(void) for (ssize_t i = 0; i < (opt->len - 1) / 2; ++i) { memcpy(&entry.target, &opt->data[6 + i * sizeof(entry.target)], sizeof(entry.target)); - odhcp6c_update_entry(STATE_RA_DNS, &entry); + changed |= odhcp6c_update_entry(STATE_RA_DNS, &entry); } } } @@ -269,5 +270,5 @@ bool ra_process(void) if (found) odhcp6c_expire(); - return found; + return found && changed; } -- 2.30.2