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l2tp: Add Last Sent/Received LCP ConfReq in ICCN

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To support proxy LCP negotiation.
This commit is contained in:
Samuel Thibault 2025-03-08 23:13:23 +01:00
parent ffcaf851ca
commit 6f04a5c390
3 changed files with 54 additions and 0 deletions
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14
l2tpns.c
View file

@ -4841,6 +4841,8 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexu
session[s].ppp.phase = Establish;
session[s].ppp.lcp = Starting;
sess_local[s].lcp_last_received_confreq_n = 0;
sess_local[s].lcp_last_sent_confreq_n = 0;
STAT(session_created);
break;
@ -4867,6 +4869,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexu
LOG(3, s, t, "Received ICRP\n");
if (session[s].forwardtosession)
{
sessionidt fs = session[s].forwardtosession;
controlt *c = controlnew(12); // ICCN
session[s].opened = time_now;
@ -4879,6 +4882,17 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexu
control32(c, 19, 1, 1); // Framing Type
control32(c, 24, 10000000, 1); // Tx Connect Speed
if (sess_local[fs].lcp_last_sent_confreq_n)
// Last Sent LCP ConfReq
controlb(c, 27, sess_local[fs].lcp_last_sent_confreq,
sess_local[fs].lcp_last_sent_confreq_n, 0);
if (sess_local[fs].lcp_last_received_confreq_n)
// Last Received LCP ConfReq
controlb(c, 28, sess_local[fs].lcp_last_received_confreq,
sess_local[fs].lcp_last_received_confreq_n, 0);
controladd(c, asession, t); // send the message
LOG(3, s, t, "Sending ICCN\n");
}

10
l2tpns.h
View file

@ -393,6 +393,9 @@ fragmentationt;
#define AUTHPAP 1 // allow PAP
#define AUTHCHAP 2 // allow CHAP
#define MAXLCPLENGTH 128 // Arbitrary, not too large to avoid consuming too
// much memory, but not too short for actual uses
typedef struct
{
// packet counters
@ -416,6 +419,13 @@ typedef struct
// authentication to use
int lcp_authtype;
// Last Received LCP ConfReq and its length
uint8_t lcp_last_received_confreq[MAXLCPLENGTH];
int lcp_last_received_confreq_n;
// Last Sent LCP ConfReq and its length
uint8_t lcp_last_sent_confreq[MAXLCPLENGTH];
int lcp_last_sent_confreq_n;
// our MRU
uint16_t ppp_mru;

30
ppp.c
View file

@ -425,6 +425,8 @@ void lcp_open(sessionidt s, tunnelidt t)
void lcp_restart(sessionidt s)
{
session[s].ppp.phase = Establish;
sess_local[s].lcp_last_received_confreq_n = 0;
sess_local[s].lcp_last_sent_confreq_n = 0;
// This-Layer-Down
change_state(s, ipcp, Initial);
change_state(s, ipv6cp, Initial);
@ -851,6 +853,18 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
if (config->debug > 3) dumplcp(response, l);
if (*response == ConfigAck && l - 4 <= sizeof(sess_local[s].lcp_last_received_confreq))
{
memcpy(sess_local[s].lcp_last_received_confreq, p + 4, l - 4);
sess_local[s].lcp_last_received_confreq_n = l - 4;
}
else
{
LOG(3, s, t, "their LCP ConfigReq is too long for proxying\n");
dumplcp(p, l);
sess_local[s].lcp_last_received_confreq_n = 0;
}
tunnelsend(b, l + (response - b), t);
}
else if (*p == ConfigNak || *p == ConfigRej)
@ -859,6 +873,10 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
uint8_t *o = (p + 4);
int authtype = -1;
// They didn't like our config
sess_local[s].lcp_last_sent_confreq_n = 0;
while (x > 2)
{
int type = o[0];
@ -2800,6 +2818,18 @@ void sendlcp(sessionidt s, tunnelidt t)
LOG_HEX(5, "PPPLCP", q, l - q);
if (config->debug > 3) dumplcp(q, l - q);
if (l - (q + 4) <= sizeof(sess_local[s].lcp_last_sent_confreq))
{
memcpy(sess_local[s].lcp_last_sent_confreq, q + 4, l - (q + 4));
sess_local[s].lcp_last_sent_confreq_n = l - (q + 4);
}
else
{
LOG(3, s, t, "our LCP ConfigReq is too long for proxying\n");
dumplcp(q, l - q);
sess_local[s].lcp_last_sent_confreq_n = 0;
}
tunnelsend(b, (l - b), t);
restart_timer(s, lcp);
}