Add lapd.c and lapd.h

3 files changed, 420 insertions, 4 deletions

diff --git a/openbsc/src/input/dahdi.c b/openbsc/src/input/dahdi.c
index a4aeb9298..db7278305 100644
--- a/openbsc/src/input/dahdi.c
+++ b/openbsc/src/input/dahdi.c
@@ -92,7 +92,7 @@ static int handle_ts1_read(struct bsc_fd *bfd)
 	unsigned int ts_nr = bfd->priv_nr;
 	struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1];
 	struct e1inp_sign_link *link;
-	struct msgb *msg = msgb_alloc(TS1_ALLOC_SIZE, "mISDN TS1");
+	struct msgb *msg = msgb_alloc(TS1_ALLOC_SIZE, "DAHDI TS1");
 	struct sockaddr_mISDN l2addr;
 	struct mISDNhead *hh;
 	socklen_t alen;
@@ -389,7 +389,6 @@ static int mi_e1_setup(struct e1inp_line *line, int release_l2)
 		char openstr[128];
 		struct e1inp_ts *e1i_ts = &line->ts[idx];
 		struct bsc_fd *bfd = &e1i_ts->driver.misdn.fd;
-		struct sockaddr_mISDN addr;
 
 		bfd->data = line;
 		bfd->priv_nr = ts;
@@ -437,7 +436,7 @@ int mi_e1_line_update(struct e1inp_line *line)
 
 	if (!line->driver) {
 		/* this must be the first update */
-		line->driver = &misdn_driver;
+		line->driver = &dahdi_driver;
 	} else {
 		/* this is a subsequent update */
 		/* FIXME: first close all sockets */
@@ -445,9 +444,10 @@ int mi_e1_line_update(struct e1inp_line *line)
 		return 0;
 	}
 
-	if (line->driver != &misdn_driver)
+	if (line->driver != &dahdi_driver)
 		return -EINVAL;
 
+#if 0
 	/* open the ISDN card device */
 	sk = socket(PF_ISDN, SOCK_RAW, ISDN_P_BASE);
 	if (sk < 0) {
@@ -485,6 +485,7 @@ int mi_e1_line_update(struct e1inp_line *line)
 		fprintf(stderr, "error: card is not of type E1 (NT-mode)\n");
 		return -EINVAL;
 	}
+#endif
 
 	ret = mi_e1_setup(line, 1);
 	if (ret)
diff --git a/openbsc/src/input/lapd.c b/openbsc/src/input/lapd.c
new file mode 100644
index 000000000..5e8e9369a
--- /dev/null
+++ b/openbsc/src/input/lapd.c
@@ -0,0 +1,396 @@
+
+/*
+ * minimal standalone network-side lap-d implementation
+ * oystein@homelien.no, 2009
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include "lapd.h"
+#include "openbsc/debug.h"
+
+#define	DEBUG_LAPD(f, args...)	{ printf("lapd "); printf(f, ## args); };
+
+typedef enum {
+	LAPD_TEI_NONE	= 0,
+
+	LAPD_TEI_ASSIGNED,
+
+	LAPD_TEI_ACTIVE,
+} lapd_tei_state;
+
+const char *lapd_tei_states[] = {
+	"NONE",
+	"ASSIGNED",
+	"ACTIVE",
+};
+
+typedef enum {
+	LAPD_TYPE_NONE	= 0,
+
+	LAPD_TYPE_I,
+	LAPD_TYPE_S,
+	LAPD_TYPE_U,
+} lapd_msg_type;
+
+typedef enum {
+	// commands/responses
+	LAPD_CMD_NONE = 0,
+
+	LAPD_CMD_I,
+	LAPD_CMD_RR,
+	LAPD_CMD_RNR,
+	LAPD_CMD_REJ,
+
+	LAPD_CMD_SABME,
+	LAPD_CMD_DM,
+	LAPD_CMD_UI,
+	LAPD_CMD_DISC,
+	LAPD_CMD_UA,
+	LAPD_CMD_FRMR,
+	LAPD_CMD_XID,
+} lapd_cmd_type;
+
+const char *lapd_cmd_types[] = {
+	"NONE",
+
+	"I",
+	"RR",
+	"RNR",
+	"REJ",
+
+	"SABME",
+	"DM",
+	"UI",
+	"DISC",
+	"UA",
+	"FRMR",
+	"XID",
+
+
+};
+
+
+
+const char	*lapd_msg_types = "?ISU";
+const int	network_side = 1; // 0 for user side
+
+typedef struct {
+	int				tei;
+	int				sapi;
+	//A valid N(R) value is one that is in the range V(A) ≤ N(R) ≤ V(S).
+	int				vs; // next to be transmitted
+	int				va; // last acked by peer
+	int				vr; // next expected to be received
+	lapd_tei_state	state;
+} lapd_tei_t;
+
+// 3.5.2.2   Send state variable V(S)
+// Each point-to-point data link connection endpoint shall have an associated V(S) when using I frame
+// commands. V(S) denotes the sequence number of the next I frame to be transmitted. The V(S) can
+// take on the value 0 through n minus 1. The value of V(S) shall be incremented by 1 with each
+// successive I frame transmission, and shall not exceed V(A) by more than the maximum number of
+// outstanding I frames k. The value of k may be in the range of 1 ≤ k ≤ 127.
+//
+// 3.5.2.3   Acknowledge state variable V(A)
+// Each point-to-point data link connection endpoint shall have an associated V(A) when using I frame
+// commands and supervisory frame commands/responses. V(A) identifies the last I frame that has been
+// acknowledged by its peer [V(A) − 1 equals the N(S) of the last acknowledged I frame]. V(A) can
+// take on the value 0 through n minus 1. The value of V(A) shall be updated by the valid N(R) values
+// received from its peer (see 3.5.2.6). A valid N(R) value is one that is in the range V(A) ≤ N(R) ≤
+// V(S).
+//
+// 3.5.2.5    Receive state variable V(R)
+// Each point-to-point data link connection endpoint shall have an associated V(R) when using I frame
+// commands and supervisory frame commands/responses. V(R) denotes the sequence number of the
+// next in-sequence I frame expected to be received. V(R) can take on the value 0 through n minus 1.
+// The value of V(R) shall be incremented by one with the receipt of an error-free, in-sequence I frame
+// whose N(S) equals V(R).
+//
+#define	LAPD_NS(teip) (teip->vs)
+#define	LAPD_NR(teip) (teip->vr)
+
+// 3.5.2.4    Send sequence number N(S)
+// Only I frames contain N(S), the send sequence number of transmitted I frames. At the time that an in-
+// sequence I frame is designated for transmission, the value of N(S) is set equal to V(S).
+//
+// 3.5.2.6    Receive sequence number N(R)
+// All I frames and supervisory frames contain N(R), the expected send sequence number of the next
+// received I frame. At the time that a frame of the above types is designated for transmission, the value
+// of N(R) is set equal to V(R). N(R) indicates that the data link layer entity transmitting the N(R) has
+// correctly received all I frames numbered up to and including N(R) − 1.
+
+void (*lapd_transmit_cb)(uint8_t *data, int len, void *cbdata);
+
+static lapd_tei_t tei_list[] = {
+	{ 25, 62, },
+	{ 1, 0, },
+	{ -1 },
+};
+
+lapd_tei_t *teip_from_tei(int tei) {
+	lapd_tei_t *p;
+	for (p = tei_list; p->tei != -1; p++) {
+		if (p->tei == tei) return p;
+	};
+	return NULL;
+};
+
+void lapd_tei_set_state(lapd_tei_t *teip, int newstate) {
+	DEBUG_LAPD("state change on tei %d: %s -> %s\n", teip->tei, lapd_tei_states[teip->state], lapd_tei_states[newstate]);
+	teip->state = newstate;
+};
+
+void lapd_tei_receive(uint8_t *data, int len, void *cbdata) {
+	//DEBUG_LAPD("tei receive %p, %d\n", data, len);
+	int entity = data[0];
+	int	ref = data[1];
+	int mt = data[3];
+	int	action = data[4] >> 1;
+	int	e = data[4] & 1;
+	//DEBUG_LAPD("tei mgmt: entity %x, ref %x, mt %x, action %x, e %x\n", entity, ref, mt, action, e);
+
+	switch (mt) {
+		case 0x01: {// identity request
+			int tei = action;
+			DEBUG_LAPD("tei mgmt: identity request, accepting tei %d\n", tei);
+			//printf("tei: %d\n", tei);
+			uint8_t resp[8];
+			memmove(resp, "\xfe\xff\x03\x0f\x00\x00\x02\x00", 8);
+			resp[7] = (tei << 1) | 1;
+			lapd_transmit_cb(resp, 8, cbdata);
+			lapd_tei_t *teip = teip_from_tei (tei);
+			if (teip->state == LAPD_TEI_NONE)
+				lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED);
+			break; }
+		default: 
+			DEBUG_LAPD("tei mgmt: unknown mt %x action %x\n", mt, action);
+			assert(0);
+	};
+};
+
+uint8_t *lapd_receive(uint8_t *data, int len, int *ilen, lapd_mph_type *prim, void *cbdata) {
+#if 0
+	DEBUG_LAPD("receive %p, %d\n", data, len);
+	hexdump(data, len);
+#endif
+
+	*ilen = 0;
+	*prim = 0;
+
+	if (len < 2) {
+		DEBUG_LAPD("len %d < 2\n", len);
+		return NULL;
+	};
+
+	if ((data[0] & 1) != 0 || (data[1] & 1) != 1) {
+		DEBUG_LAPD("address field %x/%x not well formed\n", data[0], data[1]);
+		return NULL;
+	};
+
+	int	sapi = data[0] >> 2;
+	int cr = (data[0] >> 1) & 1;
+	int tei = data[1] >> 1;
+	int command = network_side ^ cr;
+	//DEBUG_LAPD("  address sapi %x tei %d cmd %d cr %d\n", sapi, tei, command, cr);
+
+	if (len < 3) {
+		DEBUG_LAPD("len %d < 4\n", len);
+		return NULL;
+	};
+
+	lapd_msg_type typ = 0;
+	lapd_cmd_type cmd = 0;
+	int	pf = -1;
+	int	ns = -1;
+	int	nr = -1;
+	if ((data[2] & 1) == 0) {
+		typ = LAPD_TYPE_I;
+		assert(len >= 4);
+		ns = data[2] >> 1;
+		nr = data[3] >> 1;
+		pf = data[3] & 1;
+		cmd = LAPD_CMD_I;
+	} else if ((data[2] & 3) == 1) {
+		typ = LAPD_TYPE_S;
+		assert(len >= 4);
+		nr = data[3] >> 1;
+		pf = data[3] & 1;
+		switch (data[2]) {
+			case 0x1: cmd = LAPD_CMD_RR; break;
+			case 0x5: cmd = LAPD_CMD_RNR; break;
+			case 0x9: cmd = LAPD_CMD_REJ; break;
+			default: 
+				DEBUG_LAPD("unknown S cmd %x\n", data[2]);
+				assert(0);
+		};
+	} else if ((data[2] & 3) == 3) {
+		typ = LAPD_TYPE_U;
+		pf = (data[2] >> 4) & 1;
+		int val = data[2] & ~(1<<4);
+		switch (val) {
+			case 0x6f: cmd = LAPD_CMD_SABME; break;
+			case 0x0f: cmd = LAPD_CMD_DM; break;
+			case 0x03: cmd = LAPD_CMD_UI; break;
+			case 0x43: cmd = LAPD_CMD_DISC; break;
+			case 0x63: cmd = LAPD_CMD_UA; break;
+			case 0x87: cmd = LAPD_CMD_FRMR; break;
+			case 0xaf: cmd = LAPD_CMD_XID; break;
+	
+			default: 
+				DEBUG_LAPD("unknown U cmd %x (pf %x data %x)\n", val, pf, data[2]);
+				assert(0);
+		};
+	};
+	
+	uint8_t *contents = &data[4];
+	if (typ == LAPD_TYPE_U) contents--;
+	*ilen = len - (contents - data);
+	
+	lapd_tei_t *teip = teip_from_tei(tei);
+	if (tei == 127)
+		lapd_tei_receive(contents, *ilen, cbdata);
+
+	DEBUG_LAPD("<- %c %s sapi %x tei %3d cmd %x pf %x ns %3d nr %3d ilen %d teip %p vs %d va %d vr %d len %d\n", lapd_msg_types[typ], lapd_cmd_types[cmd], sapi, tei, command, pf, ns, nr, *ilen, teip, teip ? teip->vs : -1, teip ? teip->va : -1, teip ? teip->vr : -1, len);
+
+	if (teip) {
+		switch (cmd) {
+			case LAPD_CMD_I: {
+				if (ns != teip->vr) {
+					DEBUG_LAPD("ns %d != vr %d\n", ns, teip->vr);
+					if (ns == teip->vr-1) {
+						DEBUG_LAPD("DOUBLE FRAME, ignoring\n");
+						cmd = 0; // ignore
+					} else {
+						assert(0);
+					};
+				} else {
+					//printf("IN SEQUENCE\n");
+				};
+				teip->vr = (ns + 1) & 0x7f; // FIXME: hack!
+
+				
+				break; }
+			case LAPD_CMD_SABME: {
+				teip->vs = 0;
+				teip->vr = 0;
+				teip->va = 0;
+
+				// ua
+				uint8_t resp[8];
+				int l = 0;
+				resp[l++] = data[0];
+				resp[l++] = (tei << 1) | 1;
+				resp[l++] = 0x73;
+				lapd_transmit_cb(resp, l, cbdata);
+				
+				break; }
+			case LAPD_CMD_RR: {
+				teip->va = (nr & 0x7f);
+				if (teip->state != LAPD_TEI_ACTIVE) {
+					if (teip->state == LAPD_TEI_ASSIGNED) {
+						lapd_tei_set_state(teip, LAPD_TEI_ACTIVE);
+						*prim = LAPD_MPH_ACTIVATE_IND;
+						//printf("ASSIGNED and ACTIVE\n");
+					} else {
+#if 0
+						DEBUG_LAPD("rr in strange state, send rej\n");
+
+						// rej
+						uint8_t resp[8];
+						int l = 0;
+						resp[l++] = (teip->sapi << 2) | (network_side ? 0 : 2);
+						resp[l++] = (tei << 1) | 1;
+						resp[l++] = 0x09; //rej
+						resp[l++] = ((teip->vr+1) << 1) | 0;
+						lapd_transmit_cb(resp, l, cbdata);
+						pf = 0; // dont reply
+#endif
+					};
+				};
+				if (pf) {
+					// interrogating us, send rr
+					uint8_t resp[8];
+					int l = 0;
+					resp[l++] = data[0];
+					resp[l++] = (tei << 1) | 1;
+					resp[l++] = 0x01; // rr
+					resp[l++] = (LAPD_NR(teip) << 1) | (data[3] & 1); // pf bit from req
+	
+					lapd_transmit_cb(resp, l, cbdata);
+					
+				};
+
+				break; }
+			case LAPD_CMD_FRMR: { // frame reject
+#if 0
+				if (teip->state == LAPD_TEI_ACTIVE)
+					*prim = LAPD_MPH_DEACTIVATE_IND;
+				lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED);
+#endif
+				DEBUG_LAPD("frame reject, ignoring\n");
+				assert(0);
+				break; }
+			case LAPD_CMD_DISC: { // disconnect
+				uint8_t resp[8];
+				int l = 0;
+				resp[l++] = data[0];
+				resp[l++] = (tei << 1) | 1;
+				resp[l++] = 0x73;
+				lapd_transmit_cb(resp, l, cbdata);
+				lapd_tei_set_state(teip, LAPD_TEI_NONE);
+				break; }
+			default: 
+				DEBUG_LAPD("unknown cmd for tei %d (cmd %x)\n", tei, cmd);
+				assert(0);
+		};
+	};
+
+	//if ((*prim == 0) && (ilen > 0) && (typ != LAPD_TYPE_S)) {
+	//if (cmd == LAPD_CMD_I) {
+	if (typ == LAPD_TYPE_I) {
+		// send rr
+		// Thu Jan 22 19:17:13 2009 <4000> sangoma.c:340 read  (62/25)   4: fa 33 01 0a 
+		// lapd <- S RR sapi 3e tei  25 cmd 0 pf 0 ns  -1 nr   5 ilen 0 teip 0x613800 vs 7 va 5 vr 2 len 4
+
+		// interrogating us, send rr
+		uint8_t resp[8];
+		int l = 0;
+		resp[l++] = data[0];
+		resp[l++] = (tei << 1) | 1;
+		resp[l++] = 0x01; // rr
+		resp[l++] = (LAPD_NR(teip) << 1) | (data[3] & 1); // pf bit from req
+
+		lapd_transmit_cb(resp, l, cbdata);
+
+		*prim = LAPD_DL_DATA_IND;
+		return contents;
+	};
+
+	return NULL;
+};
+
+void lapd_transmit(int tei, uint8_t *data, int len, void *cbdata) {
+	//printf("lapd_transmit %d, %d\n", tei, len);
+	//hexdump(data, len);
+	lapd_tei_t *teip = teip_from_tei(tei);
+	//printf("teip %p\n", teip);
+
+	// prepend stuff
+	uint8_t	buf[10000];
+	memset(buf, 0, sizeof(buf));
+	memmove(buf+4, data, len);
+	len += 4;
+
+	buf[0] = (teip->sapi << 2) | (network_side ? 2 : 0);
+	buf[1] = (teip->tei << 1) | 1;
+	buf[2] = (LAPD_NS(teip) << 1);
+	buf[3] = (LAPD_NR(teip) << 1) | 0;
+
+	teip->vs = (teip->vs + 1) & 0x7f;
+
+	lapd_transmit_cb(buf, len, cbdata);
+};
+
diff --git a/openbsc/src/input/lapd.h b/openbsc/src/input/lapd.h
new file mode 100644
index 000000000..73195d6f7
--- /dev/null
+++ b/openbsc/src/input/lapd.h
@@ -0,0 +1,19 @@
+
+#include <stdint.h>
+
+typedef enum {
+	LAPD_MPH_NONE	= 0,
+
+	LAPD_MPH_ACTIVATE_IND,
+	LAPD_MPH_DEACTIVATE_IND,
+
+	LAPD_DL_DATA_IND,
+
+} lapd_mph_type;
+
+extern uint8_t *lapd_receive(uint8_t *data, int len, int *ilen, lapd_mph_type *prim, void *cbdata);
+
+extern void (*lapd_transmit_cb)(uint8_t *data, int len, void *cbdata);
+
+extern void lapd_transmit(int tei, uint8_t *data, int len, void *cbdata);
+