ppp: Move LCP received configuration parsing to a separate function

So it can be reused for proxy LCP negotiation.
This commit is contained in:
Samuel Thibault 2025-03-08 20:05:56 -05:00
parent 9425c725c9
commit 817ce35748

320
ppp.c
View file

@ -556,6 +556,169 @@ static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
tunnelsend(buf, l + (q - buf), t); tunnelsend(buf, l + (q - buf), t);
} }
// Process received LCP options from o from packet p.
// Set changed to 1 if we changed configuration that should be sent to cluster slaves, fill response on nak or rej
static void processreceivedlcpconfreq(sessionidt s, tunnelidt t, uint8_t *p, uint8_t *o, uint16_t x, int *changed, uint8_t **response)
{
static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
static uint8_t authproto[5];
uint8_t b[MAXETHER];
uint8_t *q = NULL;
while (x > 2)
{
int type = o[0];
int length = o[1];
if (length == 0 || length == 1 || type == 0 || x < length) break;
switch (type)
{
case 1: // Maximum-Receive-Unit
{
uint16_t mru = ntohs(*(uint16_t *)(o + 2));
if (mru >= MINMTU)
{
session[s].mru = mru;
(*changed)++;
break;
}
LOG(3, s, t, " Remote requesting MRU of %u. Rejecting.\n", mru);
mru = htons(MRU);
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, response, q, p, o, (uint8_t *) &mru, sizeof(mru));
}
break;
case 2: // Async-Control-Character-Map
if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
break;
LOG(3, s, t, " Remote requesting asyncmap. Rejecting.\n");
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, response, q, p, o, asyncmap, sizeof(asyncmap));
break;
case 3: // Authentication-Protocol
{
int proto = ntohs(*(uint16_t *)(o + 2));
char proto_name[] = "0x0000";
int alen;
if (proto == PPPPAP)
{
if (config->radius_authtypes & AUTHPAP)
{
sess_local[s].lcp_authtype = AUTHPAP;
break;
}
strcpy(proto_name, "PAP");
}
else if (proto == PPPCHAP)
{
if (config->radius_authtypes & AUTHCHAP
&& *(o + 4) == 5) // MD5
{
sess_local[s].lcp_authtype = AUTHCHAP;
break;
}
strcpy(proto_name, "CHAP");
}
else
sprintf(proto_name, "%#4.4x", proto);
LOG(3, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
if (alen < 2) break; // paranoia
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, response, q, p, o, authproto + 2, alen - 2);
if (q && **response == ConfigNak &&
config->radius_authtypes != config->radius_authprefer)
{
// alternate type
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
if (alen < 2) break;
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, response, q, p, o, authproto + 2, alen - 2);
}
break;
}
break;
case 4: // Quality-Protocol
case 5: // Magic-Number
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
break;
case 17: // Multilink Max-Receive-Reconstructed-Unit
{
uint16_t mrru = ntohs(*(uint16_t *)(o + 2));
session[s].mrru = mrru;
(*changed)++;
LOG(3, s, t, " Received PPP LCP option MRRU: %d\n",mrru);
}
break;
case 18: // Multilink Short Sequence Number Header Format
{
session[s].mssf = 1;
(*changed)++;
LOG(3, s, t, " Received PPP LCP option MSSN format\n");
}
break;
case 19: // Multilink Endpoint Discriminator
{
uint8_t epdis_class = o[2];
int addr;
session[s].epdis.addr_class = epdis_class;
session[s].epdis.length = length - 3;
if (session[s].epdis.length > 20)
{
LOG(1, s, t, "Error: received EndDis Address Length more than 20: %d\n", session[s].epdis.length);
session[s].epdis.length = 20;
}
for (addr = 0; addr < session[s].epdis.length; addr++)
session[s].epdis.address[addr] = o[3+addr];
(*changed)++;
switch (epdis_class)
{
case LOCALADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis Local Address Class: %d\n",epdis_class);
break;
case IPADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IP Address Class: %d\n",epdis_class);
break;
case IEEEMACADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IEEE MAC Address Class: %d\n",epdis_class);
break;
case PPPMAGIC:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PPP Magic No Class: %d\n",epdis_class);
break;
case PSNDN:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PSND No Class: %d\n",epdis_class);
break;
default:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis NULL Class %d\n",epdis_class);
}
}
break;
default: // Reject any unknown options
LOG(3, s, t, " Rejecting unknown PPP LCP option %d\n", type);
q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, response, q, p, o);
}
x -= length;
o += length;
}
}
// Process LCP messages // Process LCP messages
void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l) void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
{ {
@ -648,165 +811,10 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
} }
else if (*p == ConfigReq) else if (*p == ConfigReq)
{ {
int x = l - 4;
uint8_t *o = (p + 4);
uint8_t *response = 0; uint8_t *response = 0;
static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
static uint8_t authproto[5];
int changed = 0; int changed = 0;
while (x > 2) processreceivedlcpconfreq(s, t, p, p + 4, l - 4, &changed, &response);
{
int type = o[0];
int length = o[1];
if (length == 0 || length == 1 || type == 0 || x < length) break;
switch (type)
{
case 1: // Maximum-Receive-Unit
{
uint16_t mru = ntohs(*(uint16_t *)(o + 2));
if (mru >= MINMTU)
{
session[s].mru = mru;
changed++;
break;
}
LOG(3, s, t, " Remote requesting MRU of %u. Rejecting.\n", mru);
mru = htons(MRU);
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
}
break;
case 2: // Async-Control-Character-Map
if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
break;
LOG(3, s, t, " Remote requesting asyncmap. Rejecting.\n");
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
break;
case 3: // Authentication-Protocol
{
int proto = ntohs(*(uint16_t *)(o + 2));
char proto_name[] = "0x0000";
int alen;
if (proto == PPPPAP)
{
if (config->radius_authtypes & AUTHPAP)
{
sess_local[s].lcp_authtype = AUTHPAP;
break;
}
strcpy(proto_name, "PAP");
}
else if (proto == PPPCHAP)
{
if (config->radius_authtypes & AUTHCHAP
&& *(o + 4) == 5) // MD5
{
sess_local[s].lcp_authtype = AUTHCHAP;
break;
}
strcpy(proto_name, "CHAP");
}
else
sprintf(proto_name, "%#4.4x", proto);
LOG(3, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
if (alen < 2) break; // paranoia
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
if (q && *response == ConfigNak &&
config->radius_authtypes != config->radius_authprefer)
{
// alternate type
alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
if (alen < 2) break;
q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
}
break;
}
break;
case 4: // Quality-Protocol
case 5: // Magic-Number
case 7: // Protocol-Field-Compression
case 8: // Address-And-Control-Field-Compression
break;
case 17: // Multilink Max-Receive-Reconstructed-Unit
{
uint16_t mrru = ntohs(*(uint16_t *)(o + 2));
session[s].mrru = mrru;
changed++;
LOG(3, s, t, " Received PPP LCP option MRRU: %d\n",mrru);
}
break;
case 18: // Multilink Short Sequence Number Header Format
{
session[s].mssf = 1;
changed++;
LOG(3, s, t, " Received PPP LCP option MSSN format\n");
}
break;
case 19: // Multilink Endpoint Discriminator
{
uint8_t epdis_class = o[2];
int addr;
session[s].epdis.addr_class = epdis_class;
session[s].epdis.length = length - 3;
if (session[s].epdis.length > 20)
{
LOG(1, s, t, "Error: received EndDis Address Length more than 20: %d\n", session[s].epdis.length);
session[s].epdis.length = 20;
}
for (addr = 0; addr < session[s].epdis.length; addr++)
session[s].epdis.address[addr] = o[3+addr];
changed++;
switch (epdis_class)
{
case LOCALADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis Local Address Class: %d\n",epdis_class);
break;
case IPADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IP Address Class: %d\n",epdis_class);
break;
case IEEEMACADDR:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis IEEE MAC Address Class: %d\n",epdis_class);
break;
case PPPMAGIC:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PPP Magic No Class: %d\n",epdis_class);
break;
case PSNDN:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis PSND No Class: %d\n",epdis_class);
break;
default:
LOG(3, s, t, " Received PPP LCP option Multilink EndDis NULL Class %d\n",epdis_class);
}
}
break;
default: // Reject any unknown options
LOG(3, s, t, " Rejecting unknown PPP LCP option %d\n", type);
q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
}
x -= length;
o += length;
}
if (changed) if (changed)
cluster_send_session(s); cluster_send_session(s);