tunsafe-clang15/network_bsd_common.cpp
2018-08-09 14:36:45 +02:00

753 lines
19 KiB
C++

// SPDX-License-Identifier: AGPL-1.0-only
// Copyright (C) 2018 Ludvig Strigeus <info@tunsafe.com>. All Rights Reserved.
#include "network_bsd_common.h"
#include "tunsafe_endian.h"
#include "util.h"
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <signal.h>
#include <sys/socket.h>
#include <net/route.h>
#include <sys/time.h>
#include <pthread.h>
#if defined(OS_MACOSX)
#include <sys/kern_control.h>
#include <net/if_utun.h>
#include <sys/sys_domain.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <net/if_dl.h>
#elif defined(OS_FREEBSD)
#include <net/if_tun.h>
#include <net/if_dl.h>
#elif defined(OS_LINUX)
#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/prctl.h>
#include <linux/rtnetlink.h>
#endif
void SetThreadName(const char *name) {
#if defined(OS_LINUX)
prctl(PR_SET_NAME, name, 0, 0, 0);
#endif // defined(OS_LINUX)
}
#if defined(OS_MACOSX) || defined(OS_FREEBSD)
struct MyRouteMsg {
struct rt_msghdr hdr;
uint32 pad;
struct sockaddr_in target;
struct sockaddr_in netmask;
};
struct MyRouteReply {
struct rt_msghdr hdr;
uint8 buf[512];
};
// Zero gets rounded up
#if defined(OS_MACOSX)
#define RTMSG_ROUNDUP(a) ((a) ? ((((a) - 1) | (sizeof(uint32_t) - 1)) + 1) : sizeof(uint32_t))
#else
#define RTMSG_ROUNDUP(a) ((a) ? ((((a) - 1) | (sizeof(long) - 1)) + 1) : sizeof(long))
#endif
static bool GetDefaultRoute(char *iface, size_t iface_size, uint32 *gw_addr) {
int fd, pid, len;
union {
MyRouteMsg rt;
MyRouteReply rep;
};
fd = socket(PF_ROUTE, SOCK_RAW, AF_INET);
if (fd < 0)
return false;
memset(&rt, 0, sizeof(rt));
rt.hdr.rtm_type = RTM_GET;
rt.hdr.rtm_flags = RTF_UP | RTF_GATEWAY;
rt.hdr.rtm_version = RTM_VERSION;
rt.hdr.rtm_seq = 0;
rt.hdr.rtm_addrs = RTA_DST | RTA_NETMASK | RTA_IFP;
rt.target.sin_family = AF_INET;
rt.netmask.sin_family = AF_INET;
rt.target.sin_len = sizeof(struct sockaddr_in);
rt.netmask.sin_len = sizeof(struct sockaddr_in);
rt.hdr.rtm_msglen = sizeof(rt);
if (write(fd, (char*)&rt, sizeof(rt)) != sizeof(rt)) {
RERROR("PF_ROUTE write failed.");
close(fd);
return false;
}
pid = getpid();
do {
len = read(fd, (char *)&rep, sizeof(rep));
if (len <= 0) {
RERROR("PF_ROUTE read failed.");
close(fd);
return false;
}
} while (rep.hdr.rtm_seq != 0 || rep.hdr.rtm_pid != pid);
close(fd);
const struct sockaddr_dl *ifp = NULL;
const struct sockaddr_in *gw = NULL;
uint8 *pos = rep.buf;
for (int i = 1; i && i < rep.hdr.rtm_addrs; i <<= 1) {
if (rep.hdr.rtm_addrs & i) {
if (1 > rep.buf + 512 - pos)
break; // invalid
size_t len = RTMSG_ROUNDUP(((struct sockaddr*)pos)->sa_len);
if (len > rep.buf + 512 - pos)
break; // invalid
// RINFO("rtm %d %d", i, ((struct sockaddr*)pos)->sa_len);
if (i == RTA_IFP && ((struct sockaddr*)pos)->sa_len >= sizeof(struct sockaddr_dl)) {
ifp = (struct sockaddr_dl *)pos;
} else if (i == RTA_GATEWAY && ((struct sockaddr*)pos)->sa_len >= sizeof(struct sockaddr_in)) {
gw = (struct sockaddr_in *)pos;
}
pos += len;
}
}
if (ifp && ifp->sdl_nlen && ifp->sdl_nlen < iface_size) {
iface[ifp->sdl_nlen] = 0;
memcpy(iface, ifp->sdl_data, ifp->sdl_nlen);
if (gw && gw->sin_family == AF_INET) {
*gw_addr = ReadBE32(&gw->sin_addr);
return true;
}
}
// RINFO("Read %d %d %d", len, rep.hdr.rtm_addrs, (int)sizeof(struct rt_msghdr ));
return false;
}
#endif // defined(OS_MACOSX) || defined(OS_FREEBSD)
#if defined(OS_LINUX)
struct LinuxParsedRoute {
int has;
struct in_addr dst, gateway;
char ifname[IF_NAMESIZE];
};
static bool ParseLinuxRoutes(struct nlmsghdr *nl, struct LinuxParsedRoute *result) {
struct rtmsg *rt = (struct rtmsg *)NLMSG_DATA(nl);
if (rt->rtm_family != AF_INET || rt->rtm_table != RT_TABLE_MAIN)
return false;
struct rtattr *attr = (struct rtattr *)RTM_RTA(rt);
int len = RTM_PAYLOAD(nl);
int has = 0;
for(; RTA_OK(attr, len); attr = RTA_NEXT(attr, len)) {
switch(attr->rta_type) {
case RTA_OIF:
has |= 1;
if_indextoname(*(int *)RTA_DATA(attr), result->ifname);
break;
case RTA_GATEWAY:
has |= 2;
memcpy(&result->gateway, RTA_DATA(attr), sizeof(result->gateway));
break;
case RTA_DST:
has |= 4;
memcpy(&result->dst, RTA_DATA(attr), sizeof(result->dst));
break;
}
}
result->has = has;
return true;
}
static bool GetDefaultRoute(char *iface, size_t iface_size, uint32 *gw_addr) {
enum {BUFSIZE = 8192};
struct nlmsghdr *nl;
struct rtmsg *rt;
struct LinuxParsedRoute parsed_route;
char buffer[BUFSIZE];
int fd, len, pid = getpid();
bool result = false;
if ((fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
return false;
size_t msg_size = NLMSG_SPACE(sizeof(struct rtmsg));
memset(buffer, 0, msg_size);
nl = (struct nlmsghdr *)buffer;
nl->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
nl->nlmsg_type = RTM_GETROUTE;
nl->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
nl->nlmsg_seq = 1;
nl->nlmsg_pid = pid;
rt = (struct rtmsg *)NLMSG_DATA(nl);
rt->rtm_family = AF_INET;
rt->rtm_table = RT_TABLE_MAIN;
if (send(fd, nl, msg_size, 0) != msg_size) {
RERROR("write to route socket failed");
goto done;
}
do {
if ((len = recv(fd, buffer, BUFSIZE, 0)) < 0) {
RERROR("read from route socket failed");
goto done;
}
for (nl = (struct nlmsghdr *)buffer; NLMSG_OK(nl, len); nl = NLMSG_NEXT(nl, len)) {
if (nl->nlmsg_seq != 1 || nl->nlmsg_pid != pid)
continue;
if (nl->nlmsg_type == NLMSG_DONE)
goto done;
if (nl->nlmsg_type == NLMSG_ERROR) {
RERROR("Error in recieved packet");
goto done;
}
if (ParseLinuxRoutes(nl, &parsed_route) && (parsed_route.has & (1+2+4)) == (1+2)) {
size_t l = strlen(parsed_route.ifname);
if (l < iface_size) {
*gw_addr = ReadBE32(&parsed_route.gateway);
memcpy(iface, parsed_route.ifname, l + 1);
result = true;
}
}
}
} while ((nl->nlmsg_flags & NLM_F_MULTI) != 0);
done:
close(fd);
return result;
}
#endif // defined(OS_LINUX)
#if defined(OS_MACOSX)
static mach_timebase_info_data_t timebase = { 0, 0 };
static uint64_t initclock;
void InitOsxGetMilliseconds() {
if (mach_timebase_info(&timebase) != 0)
abort();
initclock = mach_absolute_time();
timebase.denom *= 1000000;
}
uint64 OsGetMilliseconds()
{
uint64_t clock = mach_absolute_time() - initclock;
return clock * (uint64_t)timebase.numer / (uint64_t)timebase.denom;
}
#else // defined(OS_MACOSX)
uint64 OsGetMilliseconds() {
struct timespec ts;
if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
//error
fprintf(stderr, "clock_gettime failed\n");
exit(1);
}
return (uint64)ts.tv_sec * 1000 + (ts.tv_nsec / 1000000);
}
#endif
void OsGetTimestampTAI64N(uint8 dst[12]) {
struct timeval tv;
gettimeofday(&tv, NULL);
uint64 secs_since_epoch = tv.tv_sec + 0x400000000000000a;
uint32 nanos = tv.tv_usec * 1000;
WriteBE64(dst, secs_since_epoch);
WriteBE32(dst + 8, nanos);
}
void OsGetRandomBytes(uint8 *data, size_t data_size) {
int fd = open("/dev/urandom", O_RDONLY);
int r = read(fd, data, data_size);
if (r < 0) r = 0;
close(fd);
for (; r < data_size; r++)
data[r] = rand() >> 6;
}
void OsInterruptibleSleep(int millis) {
usleep((useconds_t)millis * 1000);
}
#if defined(OS_MACOSX)
int open_tun(char *devname, size_t devname_size) {
struct sockaddr_ctl sc;
struct ctl_info ctlinfo = {0};
int fd;
memcpy(ctlinfo.ctl_name, UTUN_CONTROL_NAME, sizeof(UTUN_CONTROL_NAME));
for(int i = 0; i < 256; i++) {
fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
if (fd < 0) {
RERROR("socket(SYSPROTO_CONTROL) failed");
return -1;
}
if (ioctl(fd, CTLIOCGINFO, &ctlinfo) == -1) {
RERROR("ioctl(CTLIOCGINFO) failed: %d", errno);
close(fd);
return -1;
}
sc.sc_id = ctlinfo.ctl_id;
sc.sc_len = sizeof(sc);
sc.sc_family = AF_SYSTEM;
sc.ss_sysaddr = AF_SYS_CONTROL;
sc.sc_unit = i + 1;
if (connect(fd, (struct sockaddr *)&sc, sizeof(sc)) == 0) {
socklen_t devname_size2 = devname_size;
if (getsockopt(fd, SYSPROTO_CONTROL, UTUN_OPT_IFNAME, devname, &devname_size2)) {
RERROR("getsockopt(UTUN_OPT_IFNAME) failed");
close(fd);
return -1;
}
return fd;
}
close(fd);
}
return -1;
}
#elif defined(OS_FREEBSD)
int open_tun(char *devname, size_t devname_size) {
char buf[32];
int tun_fd;
// First open an existing tun device
for(int i = 0; i < 256; i++) {
sprintf(buf, "/dev/tun%d", i);
tun_fd = open(buf, O_RDWR);
if (tun_fd >= 0) goto did_open;
}
tun_fd = open("/dev/tun", O_RDWR);
if (tun_fd < 0)
return tun_fd;
did_open:
if (!fdevname_r(tun_fd, devname, devname_size)) {
RERROR("Unable to get name of tun device");
close(tun_fd);
return -1;
}
int flags = IFF_POINTOPOINT | IFF_MULTICAST;
if (ioctl(tun_fd, TUNSIFMODE, &flags) < 0) {
RERROR("ioctl(TUNSIFMODE) failed");
close(tun_fd);
return -1;
}
flags = 1;
if (ioctl(tun_fd, TUNSIFHEAD, &flags) < 0) {
RERROR("ioctl(TUNSIFHEAD) failed");
close(tun_fd);
return -1;
}
return tun_fd;
}
#elif defined(OS_LINUX)
int open_tun(char *devname, size_t devname_size) {
int fd, err;
struct ifreq ifr;
fd = open("/dev/net/tun", O_RDWR);
if (fd < 0)
return fd;
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0) {
close(fd);
return err;
}
strcpy(devname, ifr.ifr_name);
return fd;
}
#endif
int open_udp(int listen_on_port) {
int udp_fd = socket(AF_INET, SOCK_DGRAM, 0);
if (udp_fd < 0) return udp_fd;
sockaddr_in sin = {0};
sin.sin_family = AF_INET;
sin.sin_port = htons(listen_on_port);
if (bind(udp_fd, (struct sockaddr*)&sin, sizeof(sin)) != 0) {
close(udp_fd);
return -1;
}
return udp_fd;
}
TunsafeBackendBsd::TunsafeBackendBsd()
: processor_(NULL) {
}
TunsafeBackendBsd::~TunsafeBackendBsd() {
}
static uint32 CidrToNetmaskV4(int cidr) {
return cidr == 32 ? 0xffffffff : 0xffffffff << (32 - cidr);
}
static uint32 ComputeIpv4DefaultRoute(uint32 ip, uint32 netmask) {
uint32 default_route_v4 = (ip & netmask) | 1;
if (default_route_v4 == ip)
default_route_v4++;
return default_route_v4;
}
static void ComputeIpv6DefaultRoute(const uint8 *ipv6_address, uint8 ipv6_cidr, uint8 *default_route_v6) {
memcpy(default_route_v6, ipv6_address, 16);
// clear the last bits of the ipv6 address to match the cidr.
size_t n = (ipv6_cidr + 7) >> 3;
memset(&default_route_v6[n], 0, 16 - n);
if (n == 0)
return;
// adjust the final byte
default_route_v6[n - 1] &= ~(0xff >> (ipv6_cidr & 7));
// set the very last byte to something
default_route_v6[15] |= 1;
// ensure it doesn't collide
if (memcmp(default_route_v6, ipv6_address, 16) == 0)
default_route_v6[15] ^= 3;
}
void TunsafeBackendBsd::AddRoute(uint32 ip, uint32 cidr, uint32 gw) {
uint32 ip_be, gw_be;
WriteBE32(&ip_be, ip);
WriteBE32(&gw_be, gw);
AddRoute(AF_INET, &ip_be, cidr, &gw_be);
}
static void AddOrRemoveRoute(const RouteInfo &cd, bool remove) {
char buf1[kSizeOfAddress], buf2[kSizeOfAddress];
print_ip_prefix(buf1, cd.family, cd.ip, cd.cidr);
print_ip_prefix(buf2, cd.family, cd.gw, -1);
#if defined(OS_LINUX)
const char *cmd = remove ? "delete" : "add";
if (cd.family == AF_INET) {
const char *net_or_host = (cd.cidr == 32) ? "-host" : "-net";
RunCommand("/sbin/route %s %s %s gw %s", cmd, net_or_host, buf1, buf2);
} else {
const char *net_or_host = (cd.cidr == 128) ? "-host" : "-net";
RunCommand("/sbin/route %s %s inet6 %s gw %s", cmd, net_or_host, buf1, buf2);
}
#elif defined(OS_MACOSX) || defined(OS_FREEBSD)
const char *cmd = remove ? "delete" : "add";
if (cd.family == AF_INET) {
RunCommand("/sbin/route -q %s %s %s", cmd, buf1, buf2);
} else {
RunCommand("/sbin/route -q %s -inet6 %s %s", cmd, buf1, buf2);
}
#endif
}
bool TunsafeBackendBsd::AddRoute(int family, const void *dest, int dest_prefix, const void *gateway) {
RouteInfo c;
c.family = family;
size_t len = (family == AF_INET) ? 4 : 16;
memcpy(c.ip, dest, len);
memcpy(c.gw, gateway, len);
c.cidr = dest_prefix;
cleanup_commands_.push_back(c);
AddOrRemoveRoute(c, false);
return true;
}
void TunsafeBackendBsd::DelRoute(const RouteInfo &cd) {
AddOrRemoveRoute(cd, true);
}
static bool IsIpv6AddressSet(const void *p) {
return (ReadLE64(p) | ReadLE64((char*)p + 8)) != 0;
}
// Called to initialize tun
bool TunsafeBackendBsd::Initialize(const TunConfig &&config, TunConfigOut *out) override {
char def_iface[12];
char devname[16];
if (!RunPrePostCommand(config.pre_post_commands.pre_up)) {
RERROR("Pre command failed!");
return false;
}
out->enable_neighbor_discovery_spoofing = false;
if (!InitializeTun(devname))
return false;
if (config.ipv6_cidr)
RERROR("IPv6 not supported");
uint32 netmask = CidrToNetmaskV4(config.cidr);
uint32 default_route_v4 = ComputeIpv4DefaultRoute(config.ip, netmask);
RunCommand("/sbin/ifconfig %s %A mtu %d %A netmask %A up", devname, config.ip, config.mtu, config.ip, netmask);
AddRoute(config.ip & netmask, config.cidr, config.ip);
if (config.use_ipv4_default_route) {
if (config.default_route_endpoint_v4) {
uint32 gw;
if (!GetDefaultRoute(def_iface, sizeof(def_iface), &gw)) {
RERROR("Unable to determine default interface.");
return false;
}
AddRoute(config.default_route_endpoint_v4, 32, gw);
}
AddRoute(0x00000000, 1, default_route_v4);
AddRoute(0x80000000, 1, default_route_v4);
}
uint8 default_route_v6[16];
if (config.ipv6_cidr) {
static const uint8 matchall_1_route[17] = {0x80, 0, 0, 0};
char buf[kSizeOfAddress];
ComputeIpv6DefaultRoute(config.ipv6_address, config.ipv6_cidr, default_route_v6);
RunCommand("/sbin/ifconfig %s inet6 %s", devname, print_ip_prefix(buf, AF_INET6, config.ipv6_address, config.ipv6_cidr));
if (config.use_ipv6_default_route) {
if (IsIpv6AddressSet(config.default_route_endpoint_v6)) {
RERROR("default_route_endpoint_v6 not supported");
}
AddRoute(AF_INET6, matchall_1_route + 1, 1, default_route_v6);
AddRoute(AF_INET6, matchall_1_route + 0, 1, default_route_v6);
}
}
// Add all the extra routes
for (auto it = config.extra_routes.begin(); it != config.extra_routes.end(); ++it) {
if (it->size == 32) {
AddRoute(ReadBE32(it->addr), it->cidr, default_route_v4);
} else if (it->size == 128 && config.ipv6_cidr) {
AddRoute(AF_INET6, it->addr, it->cidr, default_route_v6);
}
}
RunPrePostCommand(config.pre_post_commands.post_up);
pre_down_ = std::move(config.pre_post_commands.pre_down);
post_down_ = std::move(config.pre_post_commands.post_down);
return true;
}
void TunsafeBackendBsd::CleanupRoutes() {
RunPrePostCommand(pre_down_);
for(auto it = cleanup_commands_.begin(); it != cleanup_commands_.end(); ++it)
DelRoute(*it);
cleanup_commands_.clear();
RunPrePostCommand(post_down_);
pre_down_.clear();
post_down_.clear();
}
static bool RunOneCommand(const std::string &cmd) {
RINFO("Run: %s", cmd.c_str());
int exit_code = system(cmd.c_str());
if (exit_code) {
RERROR("Run Failed (%d) : %s", exit_code, cmd.c_str());
return false;
}
return true;
}
bool TunsafeBackendBsd::RunPrePostCommand(const std::vector<std::string> &vec) {
bool success = true;
for (auto it = vec.begin(); it != vec.end(); ++it) {
success &= RunOneCommand(*it);
}
return success;
}
static TunsafeBackendBsd *g_tunsafe_backend_bsd;
static void SigAlrm(int sig) {
if (g_tunsafe_backend_bsd)
g_tunsafe_backend_bsd->HandleSigAlrm();
}
static void SigUsr1(int sig) {
}
static bool did_ctrlc;
void SigInt(int sig) {
if (did_ctrlc)
exit(1);
did_ctrlc = true;
write(1, "Ctrl-C detected. Exiting. Press again to force quit.\n", sizeof("Ctrl-C detected. Exiting. Press again to force quit.\n")-1);
if (g_tunsafe_backend_bsd)
g_tunsafe_backend_bsd->HandleExit();
}
void TunsafeBackendBsd::RunLoop() {
assert(!g_tunsafe_backend_bsd);
assert(processor_);
g_tunsafe_backend_bsd = this;
// We want an alarm signal every second.
{
struct sigaction act = {0};
act.sa_handler = SigAlrm;
if (sigaction(SIGALRM, &act, NULL) < 0) {
RERROR("Unable to install SIGALRM handler.");
return;
}
}
{
struct sigaction act = {0};
act.sa_handler = SigInt;
if (sigaction(SIGINT, &act, NULL) < 0) {
RERROR("Unable to install SIGINT handler.");
return;
}
}
{
struct sigaction act = {0};
act.sa_handler = SigUsr1;
if (sigaction(SIGUSR1, &act, NULL) < 0) {
RERROR("Unable to install SIGUSR1 handler.");
return;
}
}
#if defined(OS_LINUX) || defined(OS_FREEBSD)
{
struct itimerspec tv = {0};
struct sigevent sev;
timer_t timer_id;
tv.it_interval.tv_sec = 1;
tv.it_value.tv_sec = 1;
sev.sigev_notify = SIGEV_SIGNAL;
sev.sigev_signo = SIGALRM;
sev.sigev_value.sival_ptr = NULL;
if (timer_create(CLOCK_MONOTONIC, &sev, &timer_id) < 0) {
RERROR("timer_create failed");
return;
}
if (timer_settime(timer_id, 0, &tv, NULL) < 0) {
RERROR("timer_settime failed");
return;
}
}
#elif defined(OS_MACOSX)
ualarm(1000000, 1000000);
#endif
RunLoopInner();
g_tunsafe_backend_bsd = NULL;
}
void InitCpuFeatures();
void Benchmark();
uint32 g_ui_ip;
const char *print_ip(char buf[kSizeOfAddress], in_addr_t ip) {
snprintf(buf, kSizeOfAddress, "%d.%d.%d.%d", (ip >> 24) & 0xff, (ip >> 16) & 0xff, (ip >> 8) & 0xff, (ip >> 0) & 0xff);
return buf;
}
class MyProcessorDelegate : public ProcessorDelegate {
public:
virtual void OnConnected(in_addr_t my_ip) {
if (my_ip != g_ui_ip) {
if (my_ip) {
char buf[kSizeOfAddress];
print_ip(buf, my_ip);
RINFO("Connection established. IP %s", buf);
}
g_ui_ip = my_ip;
}
}
virtual void OnDisconnected() {
MyProcessorDelegate::OnConnected(0);
}
};
int main(int argc, char **argv) {
bool exit_flag = false;
InitCpuFeatures();
if (argc == 2 && strcmp(argv[1], "--benchmark") == 0) {
Benchmark();
return 0;
}
fprintf(stderr, "%s\n", TUNSAFE_VERSION_STRING);
if (argc < 2) {
fprintf(stderr, "Syntax: tunsafe file.conf\n");
return 1;
}
#if defined(OS_MACOSX)
InitOsxGetMilliseconds();
#endif
SetThreadName("tunsafe-m");
MyProcessorDelegate my_procdel;
TunsafeBackendBsd *socket_loop = CreateTunsafeBackendBsd();
WireguardProcessor wg(socket_loop, socket_loop, &my_procdel);
socket_loop->SetProcessor(&wg);
if (!ParseWireGuardConfigFile(&wg, argv[1], &exit_flag)) return 1;
if (!wg.Start()) return 1;
socket_loop->RunLoop();
socket_loop->CleanupRoutes();
delete socket_loop;
return 0;
}