tunnelkit/Sources/CTunnelKitCore/RoutingTable.m

163 lines
4.3 KiB
Objective-C

//
// RoutingTable.m
// TunnelKit
//
// Created by Davide De Rosa on 4/30/19.
// Copyright (c) 2021 Davide De Rosa. All rights reserved.
//
// https://github.com/passepartoutvpn
//
// This file is part of TunnelKit.
//
// TunnelKit is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// TunnelKit is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with TunnelKit. If not, see <http://www.gnu.org/licenses/>.
//
#import <sys/sysctl.h>
#import "route.h"
#import "RoutingTable.h"
#import "Allocation.h"
// adapted from: https://github.com/jianpx/ios-cabin
@interface RoutingTableEntry ()
- (instancetype)initWithRTM:(const struct rt_msghdr2 *)rtm;
@end
#pragma mark -
@interface RoutingTable ()
@property (nonatomic, strong) NSArray<RoutingTableEntry *> *ipv4;
@property (nonatomic, strong) NSArray<RoutingTableEntry *> *ipv6;
@end
@implementation RoutingTable
- (instancetype)init
{
if (!(self = [super init])) {
return nil;
}
int mib[] = { CTL_NET, PF_ROUTE, 0, 0, NET_RT_DUMP2, 0 };
const int mibLen = sizeof(mib) / sizeof(int);
size_t len;
if (sysctl(mib, mibLen, NULL, &len, NULL, 0) || (len <= 0)) {
return nil;
}
char *buf = allocate_safely(len);
if (!buf) {
return nil;
}
if (sysctl(mib, mibLen, buf, &len, NULL, 0)) {
free(buf);
return nil;
}
NSMutableArray<RoutingTableEntry *> *entries4 = [[NSMutableArray alloc] init];
NSMutableArray<RoutingTableEntry *> *entries6 = [[NSMutableArray alloc] init];
for (const char *ptr = buf; ptr < buf + len;) {
const struct rt_msghdr2 *rtm = (struct rt_msghdr2 *)ptr;
if (rtm->rtm_addrs & RTA_DST) {
struct sockaddr *dst_sa = (struct sockaddr *)(rtm + 1); // XXX: why +1 ?!?
if (((dst_sa->sa_family == AF_INET) || (dst_sa->sa_family == AF_INET6)) && !((rtm->rtm_flags & RTF_WASCLONED) && (rtm->rtm_parentflags & RTF_PRCLONING))) {
RoutingTableEntry *entry = [[RoutingTableEntry alloc] initWithRTM:rtm];
if (!entry) {
continue;
}
if (dst_sa->sa_family == AF_INET) {
[entries4 addObject:entry];
} else if (dst_sa->sa_family == AF_INET6) {
[entries6 addObject:entry];
}
}
}
ptr += rtm->rtm_msglen;
}
free(buf);
self.ipv4 = entries4;
self.ipv6 = entries6;
return self;
}
- (RoutingTableEntry *)defaultGateway4
{
for (RoutingTableEntry *entry in self.ipv4) {
if ([entry isDefault]) {
return entry;
}
}
return nil;
}
- (RoutingTableEntry *)defaultGateway6
{
for (RoutingTableEntry *entry in self.ipv6) {
if ([entry isDefault]) {
return entry;
}
}
return nil;
}
- (RoutingTableEntry *)broadestRoute4MatchingDestination:(NSString *)destination
{
RoutingTableEntry *defaultRoute;
RoutingTableEntry *minRoute;
NSInteger minPrefix = 32 + 1;
for (RoutingTableEntry *route in self.ipv4) {
if ([route isDefault]) { // leave last
defaultRoute = route;
continue;
}
if ([route matchesDestination:destination] && route.prefix < minPrefix) {
minRoute = route;
minPrefix = route.prefix;
}
}
return minRoute ?: defaultRoute;
}
- (RoutingTableEntry *)broadestRoute6MatchingDestination:(NSString *)destination
{
RoutingTableEntry *defaultRoute;
RoutingTableEntry *minRoute;
NSInteger minPrefix = 128 + 1;
for (RoutingTableEntry *route in self.ipv6) {
if ([route isDefault]) { // leave last
defaultRoute = route;
continue;
}
if ([route matchesDestination:destination] && route.prefix < minPrefix) {
minRoute = route;
minPrefix = route.prefix;
}
}
return minRoute ?: defaultRoute;
}
@end