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#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <linux/if_ppp.h>
#include <net/if.h>
#include "ppp.h"
#include "ppp_ccp.h"
#include "log.h"
#include "events.h"
#include "memdebug.h"
#define MPPE_H (1 << 24)
#define MPPE_M (1 << 7)
#define MPPE_S (1 << 6)
#define MPPE_L (1 << 5)
#define MPPE_D (1 << 4)
#define MPPE_C (1 << 0)
#define MPPE_PAD 4
static struct ccp_option_t *mppe_init(struct ppp_ccp_t *ccp);
static void mppe_free(struct ppp_ccp_t *ccp, struct ccp_option_t *opt);
static int mppe_send_conf_req(struct ppp_ccp_t *ccp, struct ccp_option_t *opt, uint8_t *ptr);
static int mppe_recv_conf_req(struct ppp_ccp_t *ccp, struct ccp_option_t *opt, uint8_t *ptr);
static void mppe_print(void (*print)(const char *fmt,...),struct ccp_option_t*, uint8_t *ptr);
struct mppe_option_t
{
struct ccp_option_t opt;
int mppe;
uint8_t recv_key[16];
uint8_t send_key[16];
int policy; // 1 - allowed, 2 - required
};
static struct ccp_option_handler_t mppe_opt_hnd = {
.init = mppe_init,
.send_conf_req = mppe_send_conf_req,
.send_conf_nak = mppe_send_conf_req,
.recv_conf_req = mppe_recv_conf_req,
.free = mppe_free,
.print = mppe_print,
};
static struct ccp_option_t *mppe_init(struct ppp_ccp_t *ccp)
{
struct mppe_option_t *mppe_opt = _malloc(sizeof(*mppe_opt));
memset(mppe_opt, 0, sizeof(*mppe_opt));
mppe_opt->mppe = -1;
mppe_opt->opt.id = CI_MPPE;
mppe_opt->opt.len = 6;
return &mppe_opt->opt;
}
static void mppe_free(struct ppp_ccp_t *ccp, struct ccp_option_t *opt)
{
struct mppe_option_t *mppe_opt = container_of(opt, typeof(*mppe_opt), opt);
_free(mppe_opt);
}
static int setup_mppe_key(int fd, int transmit, uint8_t *key)
{
struct ppp_option_data data;
uint8_t buf[6 + 16];
memset(buf, 0, sizeof(buf));
buf[0] = CI_MPPE;
buf[1] = 6;
*(uint32_t*)(buf + 2) = htonl(MPPE_S | MPPE_H);
if (key)
memcpy(buf + 6, key, 16);
memset(&data, 0, sizeof(data));
data.ptr = buf;
data.length = sizeof(buf);
data.transmit = transmit;
if (ioctl(fd, PPPIOCSCOMPRESS, &data)) {
log_ppp_warn("mppe: MPPE requested but not supported by kernel\n");
return -1;
}
return 0;
}
static int decrease_mtu(struct ppp_t *ppp)
{
struct ifreq ifr;
strcpy(ifr.ifr_name, ppp->ifname);
if (ioctl(sock_fd, SIOCGIFMTU, &ifr)) {
log_ppp_error("mppe: failed to get MTU: %s\n", strerror(errno));
return -1;
}
ifr.ifr_mtu -= MPPE_PAD;
if (ioctl(sock_fd, SIOCSIFMTU, &ifr)) {
log_ppp_error("mppe: failed to set MTU: %s\n", strerror(errno));
return -1;
}
return 0;
}
static int mppe_send_conf_req(struct ppp_ccp_t *ccp, struct ccp_option_t *opt, uint8_t *ptr)
{
struct mppe_option_t *mppe_opt = container_of(opt,typeof(*mppe_opt),opt);
struct ccp_opt32_t *opt32 = (struct ccp_opt32_t*)ptr;
if (mppe_opt->policy == 2 || mppe_opt->mppe != -1) {
opt32->hdr.id = CI_MPPE;
opt32->hdr.len = 6;
opt32->val = mppe_opt->mppe ? htonl(MPPE_S | MPPE_H) : 0;
if (mppe_opt->mppe && setup_mppe_key(ccp->ppp->unit_fd, 0, mppe_opt->recv_key))
return 0;
return 6;
}
return 0;
}
static int mppe_recv_conf_req(struct ppp_ccp_t *ccp, struct ccp_option_t *opt, uint8_t *ptr)
{
struct mppe_option_t *mppe_opt = container_of(opt, typeof(*mppe_opt), opt);
struct ccp_opt32_t *opt32 = (struct ccp_opt32_t *)ptr;
/*if (!ptr) {
if (mppe_opt->policy == 2)
return CCP_OPT_NAK;
return CCP_OPT_ACK;
}*/
if (opt32->hdr.len != 6)
return CCP_OPT_REJ;
if (mppe_opt->policy == 2) {
if (ntohl(opt32->val) != (MPPE_S | MPPE_H))
return CCP_OPT_NAK;
} else if (mppe_opt->policy == 1) {
if (ntohl(opt32->val) == (MPPE_S | MPPE_H))
mppe_opt->mppe = 1;
else if ((ntohl(opt32->val) & (MPPE_S | MPPE_H)) == (MPPE_S | MPPE_H)) {
mppe_opt->mppe = 1;
return CCP_OPT_NAK;
} else if (opt32->val) {
mppe_opt->mppe = 0;
return CCP_OPT_NAK;
} else
mppe_opt->mppe = 0;
} else
return CCP_OPT_REJ;
if (setup_mppe_key(ccp->ppp->unit_fd, 1, mppe_opt->send_key))
return CCP_OPT_REJ;
decrease_mtu(ccp->ppp);
return CCP_OPT_ACK;
}
static void mppe_print(void (*print)(const char *fmt,...),struct ccp_option_t *opt, uint8_t *ptr)
{
struct mppe_option_t *mppe_opt = container_of(opt, typeof(*mppe_opt), opt);
struct ccp_opt32_t *opt32 = (struct ccp_opt32_t *)ptr;
uint32_t bits;
if (ptr)
bits = ntohl(opt32->val);
else
if (mppe_opt->mppe)
bits = MPPE_S | MPPE_H;
else
bits = 0;
print("<mppe %sH %sM %sS %sL %sD %sC>",
bits & MPPE_H ? "+" : "-",
bits & MPPE_M ? "+" : "-",
bits & MPPE_S ? "+" : "-",
bits & MPPE_L ? "+" : "-",
bits & MPPE_D ? "+" : "-",
bits & MPPE_C ? "+" : "-"
);
}
static void ev_mppe_keys(struct ev_mppe_keys_t *ev)
{
struct mppe_option_t *mppe_opt = container_of(ccp_find_option(ev->ppp, &mppe_opt_hnd), typeof(*mppe_opt), opt);
if ((ev->type & 0x04) == 0) {
log_ppp_warn("mppe: 128-bit session keys not allowed, disabling mppe ...\n");
return;
}
memcpy(mppe_opt->recv_key, ev->recv_key, 16);
memcpy(mppe_opt->send_key, ev->send_key, 16);
mppe_opt->policy = ev->policy;
if (ev->policy == 2)
mppe_opt->mppe = 1;
}
static void __init mppe_opt_init()
{
ccp_option_register(&mppe_opt_hnd);
triton_event_register_handler(EV_MPPE_KEYS, (triton_event_func)ev_mppe_keys);
}
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