static void nPut(PPPControl *pc, struct pbuf *nb)
{
struct pbuf *b;
int c;
for(b = nb; b != NULL; b = b->next) {
if((c = sio_write(pc->fd, b->payload, b->len)) != b->len) {
PPPDEBUG((LOG_WARNING,
"PPP nPut: incomplete sio_write(%d,, %u) = %d\n", pc->fd, b->len, c));
#if LINK_STATS
lwip_stats.link.err++;
#endif /* LINK_STATS */
pc->lastXMit = 0; /* prepend PPP_FLAG to next packet */
break;
}
}
pbuf_free(nb);
#if LINK_STATS
lwip_stats.link.xmit++;
#endif /* LINK_STATS */
}
/*
* Decompress (decrypt) an MPPE packet.
*/
err_t
mppe_decompress(ppp_pcb *pcb, ppp_mppe_state *state, struct pbuf **pb)
{
struct pbuf *n0 = *pb, *n;
u8_t *pl;
u16_t ccount;
u8_t flushed;
/* MPPE Header */
if (n0->len < MPPE_OVHD) {
PPPDEBUG(LOG_DEBUG,
("mppe_decompress[%d]: short pkt (%d)\n",
pcb->netif->num, n0->len));
state->sanity_errors += 100;
goto sanity_error;
}
pl = (u8_t*)n0->payload;
flushed = MPPE_BITS(pl) & MPPE_BIT_FLUSHED;
ccount = MPPE_CCOUNT(pl);
PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: ccount %d\n",
pcb->netif->num, ccount));
/* sanity checks -- terminate with extreme prejudice */
if (!(MPPE_BITS(pl) & MPPE_BIT_ENCRYPTED)) {
PPPDEBUG(LOG_DEBUG,
("mppe_decompress[%d]: ENCRYPTED bit not set!\n",
pcb->netif->num));
state->sanity_errors += 100;
goto sanity_error;
}
if (!state->stateful && !flushed) {
PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: FLUSHED bit not set in "
"stateless mode!\n", pcb->netif->num));
state->sanity_errors += 100;
goto sanity_error;
}
if (state->stateful && ((ccount & 0xff) == 0xff) && !flushed) {
PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: FLUSHED bit not set on "
"flag packet!\n", pcb->netif->num));
state->sanity_errors += 100;
goto sanity_error;
}
/*
* Check the coherency count.
*/
if (!state->stateful) {
/* Discard late packet */
if ((ccount - state->ccount) % MPPE_CCOUNT_SPACE > MPPE_CCOUNT_SPACE / 2) {
state->sanity_errors++;
goto sanity_error;
}
/* RFC 3078, sec 8.1. Rekey for every packet. */
while (state->ccount != ccount) {
mppe_rekey(state, 0);
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
}
} else {
/* RFC 3078, sec 8.2. */
if (!state->discard) {
/* normal state */
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
if (ccount != state->ccount) {
/*
* (ccount > state->ccount)
* Packet loss detected, enter the discard state.
* Signal the peer to rekey (by sending a CCP Reset-Request).
*/
state->discard = 1;
ccp_resetrequest(pcb);
return ERR_BUF;
}
} else {
/* discard state */
if (!flushed) {
/* ccp.c will be silent (no additional CCP Reset-Requests). */
return ERR_BUF;
} else {
/* Rekey for every missed "flag" packet. */
while ((ccount & ~0xff) !=
(state->ccount & ~0xff)) {
mppe_rekey(state, 0);
state->ccount =
(state->ccount +
256) % MPPE_CCOUNT_SPACE;
}
/* reset */
state->discard = 0;
state->ccount = ccount;
/*
* Another problem with RFC 3078 here. It implies that the
* peer need not send a Reset-Ack packet. But RFC 1962
* requires it. Hopefully, M$ does send a Reset-Ack; even
* though it isn't required for MPPE synchronization, it is
* required to reset CCP state.
*/
}
}
if (flushed)
mppe_rekey(state, 0);
}
/* Hide MPPE header */
pbuf_header(n0, -(s16_t)(MPPE_OVHD));
/* Decrypt the packet. */
for (n = n0; n != NULL; n = n->next) {
arc4_crypt(&state->arc4, (u8_t*)n->payload, n->len);
if (n->tot_len == n->len) {
break;
}
}
/* good packet credit */
state->sanity_errors >>= 1;
return ERR_OK;
sanity_error:
if (state->sanity_errors >= SANITY_MAX) {
/*
* Take LCP down if the peer is sending too many bogons.
* We don't want to do this for a single or just a few
* instances since it could just be due to packet corruption.
*/
lcp_close(pcb, "Too many MPPE errors");
}
return ERR_BUF;
}
/*
* Compress (encrypt) a packet.
* It's strange to call this a compressor, since the output is always
* MPPE_OVHD + 2 bytes larger than the input.
*/
err_t
mppe_compress(ppp_pcb *pcb, ppp_mppe_state *state, struct pbuf **pb, u16_t protocol)
{
struct pbuf *n, *np;
u8_t *pl;
err_t err;
LWIP_UNUSED_ARG(pcb);
/* TCP stack requires that we don't change the packet payload, therefore we copy
* the whole packet before encryption.
*/
np = pbuf_alloc(PBUF_RAW, MPPE_OVHD + sizeof(protocol) + (*pb)->tot_len, PBUF_POOL);
if (!np) {
return ERR_MEM;
}
/* Hide MPPE header + protocol */
pbuf_header(np, -(s16_t)(MPPE_OVHD + sizeof(protocol)));
if ((err = pbuf_copy(np, *pb)) != ERR_OK) {
pbuf_free(np);
return err;
}
/* Reveal MPPE header + protocol */
pbuf_header(np, (s16_t)(MPPE_OVHD + sizeof(protocol)));
*pb = np;
pl = (u8_t*)np->payload;
state->ccount = (state->ccount + 1) % MPPE_CCOUNT_SPACE;
PPPDEBUG(LOG_DEBUG, ("mppe_compress[%d]: ccount %d\n", pcb->netif->num, state->ccount));
/* FIXME: use PUT* macros */
pl[0] = state->ccount>>8;
pl[1] = state->ccount;
if (!state->stateful || /* stateless mode */
((state->ccount & 0xff) == 0xff) || /* "flag" packet */
(state->bits & MPPE_BIT_FLUSHED)) { /* CCP Reset-Request */
/* We must rekey */
if (state->stateful) {
PPPDEBUG(LOG_DEBUG, ("mppe_compress[%d]: rekeying\n", pcb->netif->num));
}
mppe_rekey(state, 0);
state->bits |= MPPE_BIT_FLUSHED;
}
pl[0] |= state->bits;
state->bits &= ~MPPE_BIT_FLUSHED; /* reset for next xmit */
pl += MPPE_OVHD;
/* Add protocol */
/* FIXME: add PFC support */
pl[0] = protocol >> 8;
pl[1] = protocol;
/* Hide MPPE header */
pbuf_header(np, -(s16_t)MPPE_OVHD);
/* Encrypt packet */
for (n = np; n != NULL; n = n->next) {
arc4_crypt(&state->arc4, (u8_t*)n->payload, n->len);
if (n->tot_len == n->len) {
break;
}
}
/* Reveal MPPE header */
pbuf_header(np, (s16_t)MPPE_OVHD);
return ERR_OK;
}
/*
* Initialize (de)compressor state.
*/
void
mppe_init(ppp_pcb *pcb, ppp_mppe_state *state, u8_t options)
{
#if PPP_DEBUG
const u8_t *debugstr = (const u8_t*)"mppe_comp_init";
if (&pcb->mppe_decomp == state) {
debugstr = (const u8_t*)"mppe_decomp_init";
}
#endif /* PPP_DEBUG */
/* Save keys. */
MEMCPY(state->session_key, state->master_key, sizeof(state->master_key));
if (options & MPPE_OPT_128)
state->keylen = 16;
else if (options & MPPE_OPT_40)
state->keylen = 8;
else {
PPPDEBUG(LOG_DEBUG, ("%s[%d]: unknown key length\n", debugstr,
pcb->netif->num));
lcp_close(pcb, "MPPE required but peer negotiation failed");
return;
}
if (options & MPPE_OPT_STATEFUL)
state->stateful = 1;
/* Generate the initial session key. */
mppe_rekey(state, 1);
#if PPP_DEBUG
{
int i;
char mkey[sizeof(state->master_key) * 2 + 1];
char skey[sizeof(state->session_key) * 2 + 1];
PPPDEBUG(LOG_DEBUG, ("%s[%d]: initialized with %d-bit %s mode\n",
debugstr, pcb->netif->num, (state->keylen == 16) ? 128 : 40,
(state->stateful) ? "stateful" : "stateless"));
for (i = 0; i < (int)sizeof(state->master_key); i++)
sprintf(mkey + i * 2, "%02x", state->master_key[i]);
for (i = 0; i < (int)sizeof(state->session_key); i++)
sprintf(skey + i * 2, "%02x", state->session_key[i]);
PPPDEBUG(LOG_DEBUG,
("%s[%d]: keys: master: %s initial session: %s\n",
debugstr, pcb->netif->num, mkey, skey));
}
#endif /* PPP_DEBUG */
/*
* Initialize the coherency count. The initial value is not specified
* in RFC 3078, but we can make a reasonable assumption that it will
* start at 0. Setting it to the max here makes the comp/decomp code
* do the right thing (determined through experiment).
*/
state->ccount = MPPE_CCOUNT_SPACE - 1;
/*
* Note that even though we have initialized the key table, we don't
* set the FLUSHED bit. This is contrary to RFC 3078, sec. 3.1.
*/
state->bits = MPPE_BIT_ENCRYPTED;
}
/* Send a packet on the given connection. */
static err_t pppifOutput(struct netif *netif, struct pbuf *pb, struct ip_addr *ipaddr)
{
int pd = (int)netif->state;
u_short protocol = PPP_IP;
PPPControl *pc = &pppControl[pd];
u_int fcsOut = PPP_INITFCS;
struct pbuf *headMB = NULL, *tailMB = NULL, *p;
u_char c;
(void)ipaddr;
/* Validate parameters. */
/* We let any protocol value go through - it can't hurt us
* and the peer will just drop it if it's not accepting it. */
if (pd < 0 || pd >= NUM_PPP || !pc->openFlag || !pb) {
PPPDEBUG((LOG_WARNING, "pppifOutput[%d]: bad parms prot=%d pb=%p\n",
pd, protocol, pb));
#if LINK_STATS
lwip_stats.link.opterr++;
lwip_stats.link.drop++;
#endif
return ERR_ARG;
}
/* Check that the link is up. */
if (lcp_phase[pd] == PHASE_DEAD) {
PPPDEBUG((LOG_ERR, "pppifOutput[%d]: link not up\n", pd));
#if LINK_STATS
lwip_stats.link.rterr++;
lwip_stats.link.drop++;
#endif
return ERR_RTE;
}
/* Grab an output buffer. */
headMB = pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
if (headMB == NULL) {
PPPDEBUG((LOG_WARNING, "pppifOutput[%d]: first alloc fail\n", pd));
#if LINK_STATS
lwip_stats.link.memerr++;
lwip_stats.link.drop++;
#endif /* LINK_STATS */
return ERR_MEM;
}
#if VJ_SUPPORT > 0
/*
* Attempt Van Jacobson header compression if VJ is configured and
* this is an IP packet.
*/
if (protocol == PPP_IP && pc->vjEnabled) {
switch (vj_compress_tcp(&pc->vjComp, pb)) {
case TYPE_IP:
/* No change...
protocol = PPP_IP_PROTOCOL;
*/
break;
case TYPE_COMPRESSED_TCP:
protocol = PPP_VJC_COMP;
break;
case TYPE_UNCOMPRESSED_TCP:
protocol = PPP_VJC_UNCOMP;
break;
default:
PPPDEBUG((LOG_WARNING, "pppifOutput[%d]: bad IP packet\n", pd));
#if LINK_STATS
lwip_stats.link.proterr++;
lwip_stats.link.drop++;
#endif
pbuf_free(headMB);
return ERR_VAL;
}
}
#endif
tailMB = headMB;
/* Build the PPP header. */
if ((sys_jiffies() - pc->lastXMit) >= PPP_MAXIDLEFLAG)
tailMB = pppAppend(PPP_FLAG, tailMB, NULL);
pc->lastXMit = sys_jiffies();
if (!pc->accomp) {
fcsOut = PPP_FCS(fcsOut, PPP_ALLSTATIONS);
tailMB = pppAppend(PPP_ALLSTATIONS, tailMB, &pc->outACCM);
fcsOut = PPP_FCS(fcsOut, PPP_UI);
tailMB = pppAppend(PPP_UI, tailMB, &pc->outACCM);
}
if (!pc->pcomp || protocol > 0xFF) {
c = (protocol >> 8) & 0xFF;
fcsOut = PPP_FCS(fcsOut, c);
tailMB = pppAppend(c, tailMB, &pc->outACCM);
}
