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Refactor address comparison in get_sybil_list_by_ip_version

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This commit is contained in:
Nick Mathewson
2020-09-23 12:04:09 -04:00
parent 2dba667928
commit 1be9e84b9c
1 changed files with 29 additions and 28 deletions
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src/feature/dirauth/dirvote.c
+29 -28
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@@ -4208,6 +4208,20 @@ MOCK_IMPL(uint32_t,dirserv_get_bandwidth_for_router_kb,
return bw_kb;
}
/**
* Helper: compare the address of family `family` in `a` with the address in
* `b`. The family must be one of `AF_INET` and `AF_INET6`.
**/
static int
compare_routerinfo_addrs_by_family(const routerinfo_t *a,
const routerinfo_t *b,
int family)
{
const tor_addr_t *addr1 = (family==AF_INET) ? &a->ipv4_addr : &a->ipv6_addr;
const tor_addr_t *addr2 = (family==AF_INET) ? &b->ipv4_addr : &b->ipv6_addr;
return tor_addr_compare(addr1, addr2, CMP_EXACT);
}
/** Helper for sorting: compares two ipv4 routerinfos first by ipv4 address,
* and then by descending order of "usefulness"
* (see compare_routerinfo_usefulness)
@@ -4217,9 +4231,7 @@ compare_routerinfo_by_ipv4(const void **a, const void **b)
{
const routerinfo_t *first = *(const routerinfo_t **)a;
const routerinfo_t *second = *(const routerinfo_t **)b;
const tor_addr_t *first_ipv4 = &first->ipv4_addr;
const tor_addr_t *second_ipv4 = &first->ipv4_addr;
int comparison = tor_addr_compare(first_ipv4, second_ipv4, CMP_EXACT);
int comparison = compare_routerinfo_addrs_by_family(first, second, AF_INET);
if (comparison == 0) {
// If addresses are equal, use other comparison criteria
return compare_routerinfo_usefulness(first, second);
@@ -4237,9 +4249,7 @@ compare_routerinfo_by_ipv6(const void **a, const void **b)
{
const routerinfo_t *first = *(const routerinfo_t **)a;
const routerinfo_t *second = *(const routerinfo_t **)b;
const tor_addr_t *first_ipv6 = &(first->ipv6_addr);
const tor_addr_t *second_ipv6 = &(second->ipv6_addr);
int comparison = tor_addr_compare(first_ipv6, second_ipv6, CMP_EXACT);
int comparison = compare_routerinfo_addrs_by_family(first, second, AF_INET6);
// If addresses are equal, use other comparison criteria
if (comparison == 0)
return compare_routerinfo_usefulness(first, second);
@@ -4309,10 +4319,8 @@ get_sybil_list_by_ip_version(const smartlist_t *routers, sa_family_t family)
const dirauth_options_t *options = dirauth_get_options();
digestmap_t *omit_as_sybil = digestmap_new();
smartlist_t *routers_by_ip = smartlist_new();
int ipv4_addr_count = 0;
int ipv6_addr_count = 0;
tor_addr_t last_ipv6_addr, last_ipv4_addr;
int addr_comparison = 0;
int addr_count = 0;
routerinfo_t *last_ri = NULL;
/* Allow at most this number of Tor servers on a single IP address, ... */
int max_with_same_addr = options->AuthDirMaxServersPerAddr;
if (max_with_same_addr <= 0)
@@ -4325,24 +4333,17 @@ get_sybil_list_by_ip_version(const smartlist_t *routers, sa_family_t family)
smartlist_sort(routers_by_ip, compare_routerinfo_by_ipv4);
SMARTLIST_FOREACH_BEGIN(routers_by_ip, routerinfo_t *, ri) {
if (family == AF_INET6) {
addr_comparison = tor_addr_compare(&last_ipv6_addr, &(ri->ipv6_addr),
CMP_EXACT);
if (addr_comparison != 0) {
tor_addr_copy(&last_ipv6_addr, &(ri->ipv6_addr));
ipv6_addr_count = 1;
} else if (++ipv6_addr_count > max_with_same_addr) {
digestmap_set(omit_as_sybil, ri->cache_info.identity_digest, ri);
}
} else {
addr_comparison = tor_addr_compare(&last_ipv4_addr, &(ri->ipv4_addr),
CMP_EXACT);
if (addr_comparison != 0) {
tor_addr_copy(&last_ipv4_addr, &(ri->ipv4_addr));
ipv4_addr_count = 1;
} else if (++ipv4_addr_count > max_with_same_addr) {
digestmap_set(omit_as_sybil, ri->cache_info.identity_digest, ri);
}
bool addrs_equal;
if (last_ri)
addrs_equal = !compare_routerinfo_addrs_by_family(last_ri, ri, family);
else
addrs_equal = false;
if (! addrs_equal) {
last_ri = ri;
addr_count = 1;
} else if (++addr_count > max_with_same_addr) {
digestmap_set(omit_as_sybil, ri->cache_info.identity_digest, ri);
}
} SMARTLIST_FOREACH_END(ri);
smartlist_free(routers_by_ip);