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PPP, MPPE, adapt decompressor to use pbuf

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mppe_decompress() now takes a pointer to a pbuf pointer and re-use the
passed buffer for MPPE "decompression". Removed sub protocol handling
which can be shared among all decompressors in ppp.c
This commit is contained in:
Sylvain Rochet 2015-04-12 21:04:22 +02:00
parent bcfaeca373
commit ab1606a0f6
2 changed files with 21 additions and 49 deletions
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3
src/include/netif/ppp/mppe.h
View File

@ -136,8 +136,7 @@ int mppe_compress(void *arg, unsigned char *ibuf, unsigned char *obuf,
int mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit, int mppe_decomp_init(void *arg, unsigned char *options, int optlen, int unit,
int hdrlen, int mru, int debug); int hdrlen, int mru, int debug);
void mppe_decomp_reset(void *arg); void mppe_decomp_reset(void *arg);
int mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, int mppe_decompress(void *arg, struct pbuf **pb);
int osize);
void mppe_incomp(void *arg, unsigned char *ibuf, int icnt); void mppe_incomp(void *arg, unsigned char *ibuf, int icnt);
#endif /* MPPE_H */ #endif /* MPPE_H */

67
src/netif/ppp/mppe.c
View File

@ -369,41 +369,33 @@ void mppe_decomp_reset(void *arg)
* Decompress (decrypt) an MPPE packet. * Decompress (decrypt) an MPPE packet.
*/ */
int int
mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf, mppe_decompress(void *arg, struct pbuf **pb)
int osize)
{ {
struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg; struct ppp_mppe_state *state = (struct ppp_mppe_state *) arg;
struct pbuf *n0 = *pb, *n;
u8_t *pl;
unsigned ccount; unsigned ccount;
int flushed = MPPE_BITS(ibuf) & MPPE_BIT_FLUSHED; int flushed;
int sanity = 0; int sanity = 0;
if (isize <= MPPE_OVHD) { /* MPPE Header */
if (n0->len < MPPE_OVHD) {
if (state->debug) if (state->debug)
PPPDEBUG(LOG_DEBUG, PPPDEBUG(LOG_DEBUG,
("mppe_decompress[%d]: short pkt (%d)\n", ("mppe_decompress[%d]: short pkt (%d)\n",
state->unit, isize)); state->unit, n0->len));
return ERR_BUF; return ERR_BUF;
} }
/* pl = (u8_t*)n0->payload;
* Make sure we have enough room to decrypt the packet. flushed = MPPE_BITS(pl) & MPPE_BIT_FLUSHED;
* Note that for our test we add 1 byte to account for possible PFC. ccount = MPPE_CCOUNT(pl);
*/
if (osize < isize - MPPE_OVHD + 1) {
PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: osize too small! "
"(have: %d need: %d)\n", state->unit,
osize, isize - MPPE_OVHD + 1));
return ERR_BUF;
}
osize = isize - MPPE_OVHD; /* assume no PFC */
ccount = MPPE_CCOUNT(ibuf);
if (state->debug >= 7) if (state->debug >= 7)
PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: ccount %d\n", PPPDEBUG(LOG_DEBUG, ("mppe_decompress[%d]: ccount %d\n",
state->unit, ccount)); state->unit, ccount));
/* sanity checks -- terminate with extreme prejudice */ /* sanity checks -- terminate with extreme prejudice */
if (!(MPPE_BITS(ibuf) & MPPE_BIT_ENCRYPTED)) { if (!(MPPE_BITS(pl) & MPPE_BIT_ENCRYPTED)) {
PPPDEBUG(LOG_DEBUG, PPPDEBUG(LOG_DEBUG,
("mppe_decompress[%d]: ENCRYPTED bit not set!\n", ("mppe_decompress[%d]: ENCRYPTED bit not set!\n",
state->unit)); state->unit));
@ -491,40 +483,21 @@ mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
mppe_rekey(state, 0); mppe_rekey(state, 0);
} }
/* /* Hide MPPE header */
* Fill in the first part of the PPP header. The protocol field pbuf_header(n0, -(s16_t)(MPPE_OVHD));
* comes from the decrypted data.
*/
ibuf += MPPE_OVHD;
isize -= MPPE_OVHD;
/* /* Decrypt the packet. */
* Decrypt the first byte in order to check if it is for (n = n0; n != NULL; n = n->next) {
* a compressed or uncompressed protocol field. arc4_crypt(&state->arc4, (u8_t*)n->payload, n->len);
*/ if (n->tot_len == n->len) {
obuf[0] = ibuf[0]; break;
arc4_crypt(&state->arc4, obuf, 1); }
/*
* Do PFC decompression.
* This would be nicer if we were given the actual sk_buff
* instead of a char *.
*/
if ((obuf[0] & 0x01) != 0) {
obuf[1] = obuf[0];
obuf[0] = 0;
obuf++;
osize++;
} }
/* And finally, decrypt the rest of the packet. */
MEMCPY(obuf+1, ibuf+1, isize-1);
arc4_crypt(&state->arc4, obuf+1, isize-1);
/* good packet credit */ /* good packet credit */
state->sanity_errors >>= 1; state->sanity_errors >>= 1;
return osize; return n0->tot_len;
} }
/* /*