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mongoose/src/l2_ppp.c
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robert c113922e19 Fix s_link duplicate
2026-05-19 08:31:15 -04:00

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#include "l2.h"
#include "log.h"
#include "net.h"
#include "net_builtin.h"
#include "printf.h"
#include "util.h"
#if MG_ENABLE_TCPIP
#if defined(__DCC__)
#pragma pack(1)
#else
#pragma pack(push, 1)
#endif
// all in network order
struct ppp { // RFC-1661
uint16_t proto;
};
struct lcp { // RFC-1661
uint8_t code, id;
uint16_t len;
};
struct ipcp { // RFC-1332
uint8_t code, id;
uint16_t len;
};
struct ipv6cp { // RFC-5072
uint8_t code, id;
uint16_t len;
};
struct hdlc_ { // RFC-1662, "PPP in HDLC-like Framing"
uint8_t addr, ctrl;
};
struct pppoe { // RFC-2516, "A Method for Transmitting PPP Over Ethernet
// (PPPoE)"
uint8_t vertype, code;
uint16_t id, len;
};
#if defined(__DCC__)
#pragma pack(0)
#else
#pragma pack(pop)
#endif
#define MG_PPP_ADDR 0xff
#define MG_PPP_CTRL 0x03
#define MG_PPP_PROTO_IP 0x0021
#define MG_PPP_PROTO_IPV6 0x0057
#define MG_PPP_PROTO_LCP 0xc021
#define MG_PPP_PROTO_IPCP 0x8021
#define MG_PPP_PROTO_IPV6CP 0x8057
#define MG_PPP_PROTO_PAP 0xc023
#define MG_PPP_PROTO_CHAP 0xc223
#define MG_PPP_LCP_CFG_REQ 1
#define MG_PPP_LCP_CFG_ACK 2
#define MG_PPP_LCP_CFG_NACK 3
#define MG_PPP_LCP_CFG_REJECT 4
#define MG_PPP_LCP_CFG_TERM_REQ 5
#define MG_PPP_LCP_CFG_TERM_ACK 6
#define MG_PPP_LCP_REJECT 8
#define MG_PPP_LCP_ECHO_REQ 9
#define MG_PPP_LCP_ECHO_REPLY 10
#define MG_PPP_IPCP_CFG_REQ 1
#define MG_PPP_IPCP_CFG_ACK 2
#define MG_PPP_IPCP_CFG_NACK 3
#define MG_PPP_IPCP_CFG_REJECT 4
#define MG_PPP_IPCP_OPT_IPADDR 3
#define MG_PPP_IPV6CP_CFG_REQ 1
#define MG_PPP_IPV6CP_CFG_ACK 2
#define MG_PPP_IPV6CP_CFG_NACK 3
#define MG_PPP_IPV6CP_CFG_REJECT 4
#define MG_PPP_IPV6CP_OPT_IFCID 1
#define MG_PPPoE_PADI 0x09
#define MG_PPPoE_PADO 0x07
#define MG_PPPoE_PADR 0x19
#define MG_PPPoE_PADS 0x65
#define MG_PPPoE_PADT 0xa7
#define MG_PPPoE_ST_DISC 0 // Discovery phase, see what servers are out there
#define MG_PPPoE_ST_REQ 1 // Chose a server, request a session and wait
#define MG_PPPoE_ST_SESS 2 // Session established, PPP traffic is exchanged
#define PDIFF(a, b) ((size_t) (((char *) (b)) - ((char *) (a))))
static bool s_lcpup = false; // ************ THESE SHOULD MOVE TO A struct
// mg_l2data *******************************
static uint8_t s_state = MG_PPPoE_ST_DISC;
static uint16_t s_id;
void mg_l2_ppp_init(struct mg_tcpip_if *ifp) {
ifp->mtu = 1500;
ifp->framesize = 1500 + sizeof(struct ppp) + sizeof(struct hdlc_);
}
extern void mg_l2_eth_init(struct mg_tcpip_if *);
void mg_l2_pppoe_init(struct mg_tcpip_if *ifp) {
mg_l2_eth_init(ifp);
ifp->mtu = ifp->mtu - (uint16_t) (sizeof(struct pppoe) +
sizeof(struct ppp)); // 1500 --> 1492
}
bool mg_l2_ppp_poll(struct mg_tcpip_if *ifp, bool expired_1000ms) {
if (expired_1000ms && ifp->state == MG_TCPIP_STATE_DOWN) s_lcpup = false;
return s_lcpup;
}
static uint8_t *hdlc_header(uint8_t *p) {
struct hdlc_ *hdlc = (struct hdlc_ *) p;
hdlc->addr = MG_PPP_ADDR;
hdlc->ctrl = MG_PPP_CTRL;
return (uint8_t *) (hdlc + 1);
}
static uint8_t *ppp_header(uint16_t proto, uint8_t *p) {
struct ppp *ppp = (struct ppp *) p;
ppp->proto = mg_htons(proto);
return (uint8_t *) (ppp + 1);
}
static uint8_t *l2_ppp_header(enum mg_l2proto proto, uint8_t *p) {
uint16_t ppp_proto = proto == MG_TCPIP_L2PROTO_IPV4 ? MG_PPP_PROTO_IP
: proto == MG_TCPIP_L2PROTO_IPV4 ? MG_PPP_PROTO_IPV6
: 0;
return ppp_header(ppp_proto, p);
}
uint8_t *mg_l2_ppp_header(struct mg_tcpip_if *ifp, enum mg_l2proto proto,
struct mg_l2addr *src, struct mg_l2addr *dst,
uint8_t *frame) {
(void) ifp;
(void) src;
(void) dst;
return l2_ppp_header(proto, hdlc_header(frame));
}
extern uint8_t *mg_l2_eth_header(struct mg_tcpip_if *ifp, enum mg_l2proto proto,
struct mg_l2addr *src, struct mg_l2addr *dst,
uint8_t *frame);
static uint8_t *pppoe_header(struct mg_tcpip_if *ifp, enum mg_l2proto proto,
uint8_t code, uint16_t id, struct mg_l2addr *src,
struct mg_l2addr *dst, uint8_t *frame) {
struct pppoe *pppoe =
(struct pppoe *) mg_l2_eth_header(ifp, proto, src, dst, frame);
pppoe->vertype = 0x11;
pppoe->code = code;
pppoe->id = id;
return (uint8_t *) (pppoe + 1);
}
uint8_t *mg_l2_pppoe_header(struct mg_tcpip_if *ifp, enum mg_l2proto proto,
struct mg_l2addr *src, struct mg_l2addr *dst,
uint8_t *frame) {
(void) dst;
return l2_ppp_header(proto, pppoe_header(ifp, MG_TCPIP_L2PROTO_PPPoE_SESS, 0,
s_id, src, dst, frame));
}
// Calculate FCS/CRC for PPP frames. Could be implemented faster using lookup
// tables.
static uint16_t fcs_do(uint8_t *frame, size_t len) {
uint32_t fcs = 0xffff;
unsigned int j;
for (j = 0; j < len; j++) {
unsigned int i;
uint8_t x = frame[j];
for (i = 0; i < 8; i++) {
fcs = ((fcs ^ x) & 1) ? (fcs >> 1) ^ 0x8408 : fcs >> 1;
x >>= 1;
}
}
return (uint16_t) (fcs & 0xffff);
}
size_t mg_l2_ppp_trailer(struct mg_tcpip_if *ifp, size_t len, uint8_t *cur) {
uint16_t crc;
uint8_t *frame;
len += sizeof(struct ppp) + sizeof(struct hdlc_);
frame = cur - len;
crc = fcs_do(frame, len);
*cur++ = (uint8_t) ~crc; // add CRC, note the byte order
*cur++ = (uint8_t) (~crc >> 8);
// there is no len field in PPP
(void) ifp;
return len + 2;
}
extern size_t mg_l2_eth_trailer(struct mg_tcpip_if *, size_t, uint8_t *);
static size_t pppoe_trailer(struct mg_tcpip_if *ifp, size_t len, uint8_t *cur) {
struct pppoe *pppoe = (struct pppoe *) (cur - len - sizeof(struct pppoe));
pppoe->len = mg_htons((uint16_t) len);
return mg_l2_eth_trailer(ifp, PDIFF(pppoe, cur), cur);
}
size_t mg_l2_pppoe_trailer(struct mg_tcpip_if *ifp, size_t len, uint8_t *cur) {
return pppoe_trailer(ifp, len + sizeof(struct ppp), cur);
}
size_t mg_l2_driver_output(struct mg_tcpip_if *ifp, size_t len);
static uint8_t *ppp_tx_frame_header(struct mg_tcpip_if *ifp, uint16_t proto) {
uint8_t *l2p = (uint8_t *) ifp->tx.buf;
if (ifp->l2type == MG_TCPIP_L2_PPP)
return ppp_header(proto, hdlc_header(l2p));
return ppp_header(proto, pppoe_header(ifp, MG_TCPIP_L2PROTO_PPPoE_SESS, 0,
s_id, (struct mg_l2addr *) ifp->mac,
(struct mg_l2addr *) ifp->gwmac, l2p));
}
static size_t ppp_tx_frame_trailer(struct mg_tcpip_if *ifp, size_t len,
uint8_t *cur) {
return mg_l2_driver_output(ifp, ifp->l2type == MG_TCPIP_L2_PPPoE
? mg_l2_pppoe_trailer(ifp, len, cur)
: mg_l2_ppp_trailer(ifp, len, cur));
}
// Transmit a single PPP frame for the given protocol
static size_t ppp_tx_frame(struct mg_tcpip_if *ifp, uint16_t proto,
uint8_t *data, size_t datasz) {
uint8_t *pay = ppp_tx_frame_header(ifp, proto);
memcpy(pay, data, datasz);
return ppp_tx_frame_trailer(ifp, datasz, pay + datasz);
}
static void ppp_handle_lcp(struct mg_tcpip_if *ifp, uint8_t *lcpp,
size_t lcpsz) {
uint8_t id;
uint16_t len;
struct lcp *lcp = (struct lcp *) lcpp;
if (lcpsz < sizeof(*lcp)) return;
id = lcp->id;
len = mg_ntohs(lcp->len);
switch (lcp->code) {
case MG_PPP_LCP_CFG_REQ: {
if (len == sizeof(*lcp)) {
MG_DEBUG(("LCP config request of %d bytes, acknowledging...", len));
lcp->code = MG_PPP_LCP_CFG_ACK;
ppp_tx_frame(ifp, MG_PPP_PROTO_LCP, lcpp, len);
lcp->code = MG_PPP_LCP_CFG_REQ;
ppp_tx_frame(ifp, MG_PPP_PROTO_LCP, lcpp, len);
} else {
MG_DEBUG(("LCP config request of %d bytes, rejecting...", len));
lcp->code = MG_PPP_LCP_CFG_REJECT;
ppp_tx_frame(ifp, MG_PPP_PROTO_LCP, lcpp, len);
}
} break;
case MG_PPP_LCP_CFG_ACK:
s_lcpup = true;
break;
case MG_PPP_LCP_CFG_TERM_REQ: {
uint8_t ack[4] = {MG_PPP_LCP_CFG_TERM_ACK, id, 0, 4};
MG_DEBUG(("LCP termination request, acknowledging..."));
ppp_tx_frame(ifp, MG_PPP_PROTO_LCP, ack, sizeof(ack));
s_lcpup = false;
} break;
case MG_PPP_LCP_ECHO_REQ: // RFC-1661 5.8: must respond
MG_DEBUG(("LCP echo request of %d bytes, replying...", len));
lcp->code = MG_PPP_LCP_ECHO_REPLY;
ppp_tx_frame(ifp, MG_PPP_PROTO_LCP, lcpp, len);
break;
}
}
static bool find_opt(const uint8_t opt, const uint8_t optlen,
const uint8_t *opts, size_t optslen, uint8_t *dest) {
uint8_t *p = (uint8_t *) opts;
while (optslen >= 2) { // parse options for requested one
if (p[1] > optslen) return false; // truncated / malformed
if (p[0] == opt && p[1] == optlen) {
memcpy(dest, p + 2, optlen - 2);
return true;
}
optslen -= p[1];
p += p[1];
}
return false;
}
static void ppp_handle_ipcp(struct mg_tcpip_if *ifp, uint8_t *ipcpp,
size_t ipcpsz) {
uint16_t len;
uint8_t id;
struct ipcp *ipcp = (struct ipcp *) ipcpp;
uint8_t req[] = {
MG_PPP_IPCP_CFG_REQ, 0, 0, 10, MG_PPP_IPCP_OPT_IPADDR, 6, 0, 0, 0, 0};
if (ipcpsz < sizeof(*ipcp)) return;
id = ipcp->id;
len = mg_ntohs(ipcp->len);
switch (ipcp->code) {
case MG_PPP_IPCP_CFG_REQ:
MG_VERBOSE(("got IPCP config request, acknowledging..."));
if (len >= 10 &&
find_opt(MG_PPP_IPCP_OPT_IPADDR, 6, (const uint8_t *) (ipcp + 1),
len - sizeof(*ipcp), (uint8_t *) &ifp->gw)) {
MG_DEBUG(("IPCP cfg, GW IP: %M", mg_print_ip4, &ifp->gw));
ipcp->code = MG_PPP_IPCP_CFG_ACK;
} else if (ifp->gw == 0) {
MG_ERROR(("Peer did not provide its IP address"));
// NOTE: We should NACK with an added option, probably we can just store
// the incoming address and offer a statically configured ifp->gw when
// theirs == 0, but it is unlikely to find such a dumb PPP server and it
// will complicate our config and this protocol state machine
ipcp->code = MG_PPP_IPCP_CFG_REJECT;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPCP, ipcpp, len);
}
ppp_tx_frame(ifp, MG_PPP_PROTO_IPCP, ipcpp, len);
req[1] = id;
memcpy(req + 6, &ifp->ip, 4); // Request config IP address or 0.0.0.0
ppp_tx_frame(ifp, MG_PPP_PROTO_IPCP, req, sizeof(req));
break;
case MG_PPP_IPCP_CFG_ACK:
// Our peer accepted our IP address
MG_VERBOSE(("got IPCP config ack"));
ifp->mask = 0xffffffff; // send to gw
ifp->state = MG_TCPIP_STATE_IP;
ifp->gw_ready = true;
break;
case MG_PPP_IPCP_CFG_NACK:
MG_VERBOSE(("got IPCP config nack"));
// NACK contains our "suggested" IP address, use it
if (len >= 10 &&
find_opt(MG_PPP_IPCP_OPT_IPADDR, 6, (const uint8_t *) (ipcp + 1),
len - sizeof(*ipcp), (uint8_t *) &ifp->ip)) {
MG_DEBUG(("IPCP cfg, IP: %M", mg_print_ip4, &ifp->ip));
ipcp->code = MG_PPP_IPCP_CFG_REQ;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPCP, ipcpp, len);
}
break;
case MG_PPP_IPCP_CFG_REJECT:
MG_ERROR(("Peer rejected our IP address, need to properly set ifp->ip"));
break;
}
}
#if MG_ENABLE_IPV6
static void ppp_handle_ipv6cp(struct mg_tcpip_if *ifp, uint8_t *ipv6cpp,
size_t ipv6cpsz) {
uint16_t len;
uint8_t id;
struct ipv6cp *ipv6cp = (struct ipv6cp *) ipv6cpp;
uint8_t req[14];
memset(req, 0, sizeof(req));
req[0] = MG_PPP_IPV6CP_CFG_REQ, req[3] = 14, req[4] = MG_PPP_IPV6CP_OPT_IFCID,
req[5] = 10;
if (ipv6cpsz < sizeof(*ipv6cp)) return;
id = ipv6cp->id;
len = mg_ntohs(ipv6cp->len);
switch (ipv6cp->code) {
case MG_PPP_IPV6CP_CFG_REQ:
MG_VERBOSE(("got IPV6CP config request..."));
if (len >= 10 &&
find_opt(
MG_PPP_IPV6CP_OPT_IFCID, 10, (const uint8_t *) (ipv6cp + 1),
len - sizeof(*ipv6cp),
(uint8_t *) &((struct mg_l2addr *) (ifp->gwmac))->addr.ieee64)) {
if (((struct mg_l2addr *) (ifp->gwmac))->addr.ieee64 != 0) {
MG_DEBUG(("IPV6CP cfg, GW IFCID: %M", mg_print_ieee64,
&((struct mg_l2addr *) (ifp->gwmac))->addr.ieee64));
ipv6cp->code = MG_PPP_IPV6CP_CFG_ACK;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPV6CP, ipv6cpp, len);
req[1] = id;
ifp->ip6ll[0] = 0, ifp->ip6ll[1] = 0; // clear any former ll address
memset(req + 6, 0, 8); // Inform ifc id 0
ppp_tx_frame(ifp, MG_PPP_PROTO_IPV6CP, req, sizeof(req));
} else {
MG_ERROR(("Peer is not able to provide its interface id"));
ipv6cp->code = MG_PPP_IPV6CP_CFG_REJECT;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPV6CP, ipv6cpp, len);
}
} else {
MG_ERROR(("Peer did not provide its interface id"));
// We should NACK with an added option, but we can't provide one for
// them
ipv6cp->code = MG_PPP_IPV6CP_CFG_REJECT;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPV6CP, ipv6cpp, len);
}
break;
case MG_PPP_IPV6CP_CFG_ACK:
// Our peer accepted our ifc id
MG_VERBOSE(("got IPV6CP config ack"));
break;
case MG_PPP_IPV6CP_CFG_NACK:
MG_VERBOSE(("got IPV6CP config nack"));
// NACK contains our "suggested" IFC id, use it
if (len >= 10 &&
find_opt(
MG_PPP_IPV6CP_OPT_IFCID, 10, (const uint8_t *) (ipv6cp + 1),
len - sizeof(*ipv6cp),
(uint8_t *) &((struct mg_l2addr *) (ifp->mac))->addr.ieee64)) {
MG_DEBUG(("IPV6CP cfg, IFCID: %M", mg_print_ieee64,
&((struct mg_l2addr *) (ifp->mac))->addr.ieee64));
ipv6cp->code = MG_PPP_IPV6CP_CFG_REQ;
ppp_tx_frame(ifp, MG_PPP_PROTO_IPV6CP, ipv6cpp, len);
} else {
MG_ERROR(("Peer is not able to offer an interface id"));
}
break;
case MG_PPP_IPV6CP_CFG_REJECT:
MG_ERROR(("Peer rejected our interface id"));
break;
}
}
#endif
static bool ppp_rx(struct mg_tcpip_if *ifp, enum mg_l2proto *proto,
struct mg_str *pay, struct mg_str *raw) {
struct ppp *ppp = (struct ppp *) pay->buf;
if (pay->len < sizeof(*ppp)) return false; // Truncated
pay->buf = (char *) (ppp + 1);
pay->len = pay->len - sizeof(*ppp);
switch (mg_ntohs(ppp->proto)) {
case MG_PPP_PROTO_LCP:
ppp_handle_lcp(ifp, (uint8_t *) pay->buf, pay->len);
return false;
case MG_PPP_PROTO_IPCP:
if (s_lcpup) ppp_handle_ipcp(ifp, (uint8_t *) pay->buf, pay->len);
return false;
case MG_PPP_PROTO_IP:
if (!s_lcpup) return false;
MG_VERBOSE(("got IP packet of %d bytes", pay->len));
*proto = MG_TCPIP_L2PROTO_IPV4;
break;
#if MG_ENABLE_IPV6
case MG_PPP_PROTO_IPV6CP:
if (s_lcpup) ppp_handle_ipv6cp(ifp, (uint8_t *) pay->buf, pay->len);
return false;
case MG_PPP_PROTO_IPV6:
if (!s_lcpup) return false;
MG_VERBOSE(("got IPv6 packet of %d bytes", pay->len));
*proto = MG_TCPIP_L2PROTO_IPV6;
break;
#endif
default: {
struct lcp rej;
uint8_t *p;
size_t msglen;
MG_DEBUG(("unknown %u-byte PPP frame with proto 0x%04x:",
pay->len + sizeof(*ppp), mg_ntohs(ppp->proto)));
if (mg_log_level >= MG_LL_DEBUG) mg_hexdump(ppp, sizeof(*ppp) + 20);
if (!s_lcpup) return false; // RFC-1661 5.7: must reject on link up
if (pay->len > (size_t) (ifp->mtu - 20))
pay->len = (size_t) (ifp->mtu - 20); // truncate to some safe limit
rej.code = MG_PPP_LCP_REJECT;
mg_random(&rej.id, sizeof(rej.id));
msglen = pay->len + sizeof(*ppp);
rej.len = mg_htons((uint16_t) (msglen + sizeof(rej)));
p = ppp_tx_frame_header(ifp, MG_PPP_PROTO_LCP);
memmove(p, &rej, sizeof(rej)); // LCP reject
memmove(p + sizeof(rej), ppp, msglen); // rejected PPP message
ppp_tx_frame_trailer(ifp, msglen + sizeof(rej), p + msglen + sizeof(rej));
}
return false;
}
(void) raw;
return true;
}
bool mg_l2_ppp_rx(struct mg_tcpip_if *ifp, enum mg_l2proto *proto,
struct mg_str *pay, struct mg_str *raw) {
struct hdlc_ *hdlc = (struct hdlc_ *) raw->buf;
if (raw->len < sizeof(*hdlc) + 2) return false; // Truncated
if (hdlc->addr == MG_PPP_ADDR && hdlc->ctrl == MG_PPP_CTRL) {
pay->buf = (char *) (hdlc + 1);
pay->len = raw->len - sizeof(*hdlc) - 2;
} else { // Address-and-Control-Field-Compressed PPP header
pay->buf = (char *) raw->buf;
pay->len = raw->len - 2;
}
return ppp_rx(ifp, proto, pay, raw);
}
extern struct mg_l2addr s_mapip;
struct mg_l2addr *mg_l2_ppp_getaddr(struct mg_tcpip_if *ifp, uint8_t *frame) {
(void) ifp;
(void) frame;
return &s_mapip; // bogus
}
extern struct mg_l2addr *mg_l2_eth_mapip(enum mg_l2addrtype, struct mg_addr *);
struct mg_l2addr *mg_l2_ppp_mapip(enum mg_l2addrtype addrtype,
struct mg_addr *addr) {
return mg_l2_eth_mapip(addrtype, addr);
}
#if MG_ENABLE_IPV6
bool mg_l2_ppp_genip6(uint64_t *ip6, uint8_t prefix_len,
struct mg_l2addr *l2addr) {
if (prefix_len > 64) {
MG_ERROR(("Prefix length > 64, UNSUPPORTED"));
return false;
}
ip6[0] = 0;
ip6[1] = l2addr->addr.ieee64;
return false;
}
bool mg_l2_ppp_ip6get(struct mg_l2addr *l2addr, uint8_t *opts, uint8_t len) {
(void) l2addr;
(void) opts;
(void) len;
return true;
}
uint8_t mg_l2_ppp_ip6put(struct mg_l2addr *l2addr, uint8_t *opts) {
(void) l2addr;
(void) opts;
return 0;
}
#endif
// Transmit a single PPPoE frame for the discovery phase
static size_t pppoe_tx_frame(struct mg_tcpip_if *ifp, uint8_t code, uint16_t id,
uint8_t *data, size_t datasz,
struct mg_l2addr *dst) {
uint8_t *l2p = (uint8_t *) ifp->tx.buf;
uint8_t *p = pppoe_header(ifp, MG_TCPIP_L2PROTO_PPPoE_DISC, code, id,
(struct mg_l2addr *) ifp->mac, dst, l2p);
memmove(p, data, datasz);
return mg_l2_driver_output(ifp, pppoe_trailer(ifp, datasz, p + datasz));
}
bool mg_l2_pppoe_poll(struct mg_tcpip_if *ifp, bool expired_1000ms) {
if (expired_1000ms && s_state == MG_PPPoE_ST_DISC &&
ifp->state == MG_TCPIP_STATE_LINK_UP) {
uint16_t tags[2];
tags[0] = mg_htons(0x0101); // Service Request
tags[1] = mg_htons(0x0000); // Any
pppoe_tx_frame(ifp, MG_PPPoE_PADI, 0, (uint8_t *) tags, sizeof(tags),
mg_l2_eth_mapip(MG_TCPIP_L2ADDR_BCAST, NULL));
MG_DEBUG(("Sent PADI"));
} else if (expired_1000ms && (s_state != MG_PPPoE_ST_SESS ||
ifp->state == MG_TCPIP_STATE_DOWN)) {
s_state = MG_PPPoE_ST_DISC;
}
return mg_l2_ppp_poll(ifp, expired_1000ms);
}
extern bool mg_l2_eth_rx(struct mg_tcpip_if *ifp, enum mg_l2proto *proto,
struct mg_str *pay, struct mg_str *raw);
extern struct mg_l2addr *mg_l2_eth_getaddr(struct mg_tcpip_if *, uint8_t *);
bool mg_l2_pppoe_rx(struct mg_tcpip_if *ifp, enum mg_l2proto *proto,
struct mg_str *pay, struct mg_str *raw) {
enum mg_l2proto eth_proto; // raw is handled by eth
struct pppoe *pppoe;
if (!mg_l2_eth_rx(ifp, &eth_proto, pay, raw)) return false;
pppoe = (struct pppoe *) pay->buf; // here we handle pay, not raw
if (pay->len < sizeof(*pppoe)) return false; // Truncated
if (eth_proto == MG_TCPIP_L2PROTO_PPPoE_DISC) {
MG_VERBOSE(("PPPoE_DISC"));
if (s_state == MG_PPPoE_ST_DISC && pppoe->code == MG_PPPoE_PADO &&
pppoe->id == 0) {
uint16_t tags[2];
bool has_cookie = false;
size_t len = pay->len - sizeof(*pppoe);
uint8_t *p = (uint8_t *) (pppoe + 1);
uint16_t taglen;
while (len >= 4) { // parse tags for a possible AC-Cookie
uint16_t curtag = *((uint16_t *) p);
taglen = mg_ntohs(*(((uint16_t *) p) + 1));
if (taglen > len - 4) return false; // truncated / malformed
if (curtag == mg_htons(0x0104)) {
has_cookie = true;
break;
}
len -= 4 + taglen;
p += 4 + taglen;
}
tags[0] = mg_htons(0x0101); // Service Request
tags[1] = mg_htons(0x0000); // Any
if (has_cookie) { // copy tags to before AC-Cookie tag in rx buffer
memcpy(p -= sizeof(tags), tags, sizeof(tags)); // point to all tags
taglen += 4 + sizeof(tags); // account for tags
} else {
p = (uint8_t *) tags;
taglen = sizeof(tags);
}
pppoe_tx_frame(ifp, MG_PPPoE_PADR, 0, p, taglen,
mg_l2_eth_getaddr(ifp, (uint8_t *) raw->buf));
MG_DEBUG(("Sent PADR"));
s_state = MG_PPPoE_ST_REQ;
} else if (s_state == MG_PPPoE_ST_REQ && pppoe->code == MG_PPPoE_PADS) {
s_id = pppoe->id;
memcpy(&ifp->gwmac,
mg_l2_eth_getaddr(ifp, (uint8_t *) raw->buf)->addr.mac, 6);
MG_DEBUG(("PPPoE session 0x%04x started", mg_ntohs(s_id)));
s_state = MG_PPPoE_ST_SESS;
} else if (s_state == MG_PPPoE_ST_SESS && pppoe->code == MG_PPPoE_PADT &&
pppoe->id == s_id) {
MG_ERROR(("Got PADT"));
s_id = 0;
s_lcpup = false;
s_state = MG_PPPoE_ST_DISC;
}
} else if (eth_proto == MG_TCPIP_L2PROTO_PPPoE_SESS &&
s_state == MG_PPPoE_ST_SESS) {
pay->buf = (char *) (pppoe + 1);
pay->len = pay->len - sizeof(*pppoe);
return ppp_rx(ifp, proto, pay, raw);
}
return false;
}
#endif
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