src: add generic channel infrastructure and A-bis IPA server support

This patch adds the generic channel infrastructure that allows to
create channel of different types. Each channel has their own
configuration functions.

  struct osmo_chan *chan;
  chan = osmo_chan_create(tall_example, CHAN_ABIS_IPA_SERVER);
  ...

  /* specific configuration functions per supported channel. */
  osmo_chan_abis_ipa_server_set_cb_signalmsg(chan, signal_msg_cb);
  osmo_chan_abis_ipa_unit_add(chan, 1801, 0);

  /* open channel. */
  osmo_chan_open(chan);

The input path requires a callback to be registered. The output path
is handled through:

  int osmo_chan_enqueue(struct osmo_chan *c, struct msgb *msg);

The msg->dst must be set (it can be taken from the original message
to route one reply).

This patch also adds A-bis IPA server support. It has been tested with
e1inp_ipa_bsc_test available in libosmo-abis.

1 files changed, 204 insertions, 0 deletions

diff --git a/src/ipa.c b/src/ipa.c
index 27df56f..a4c3a5f 100644
--- a/src/ipa.c
+++ b/src/ipa.c
@@ -1,13 +1,69 @@
 #include <stdlib.h>
 #include <arpa/inet.h>
+#include <string.h>
+#include <unistd.h>
 #include <errno.h>
 
+#include <osmocom/core/linuxlist.h>
 #include <osmocom/core/logging.h>
 #include <osmocom/core/msgb.h>
+#include <osmocom/core/select.h>
+#include <osmocom/core/talloc.h>
+
+#include <osmocom/gsm/tlv.h>
+
+#include <osmocom/netif/channel.h>
 #include <osmocom/netif/ipa.h>
 
 #define IPA_ALLOC_SIZE 1200
 
+/*
+ * Common propietary IPA messages:
+ *	- PONG: in reply to PING.
+ *	- ID_REQUEST: first messages once OML has been established.
+ *	- ID_ACK: in reply to ID_ACK.
+ */
+const uint8_t ipa_pong_msg[] = {
+	0, 1, IPAC_PROTO_IPACCESS, IPAC_MSGT_PONG
+};
+
+const uint8_t ipa_id_ack_msg[] = {
+	0, 1, IPAC_PROTO_IPACCESS, IPAC_MSGT_ID_ACK
+};
+
+const uint8_t ipa_id_req_msg[] = {
+	0, 17, IPAC_PROTO_IPACCESS, IPAC_MSGT_ID_GET,
+	0x01, IPAC_IDTAG_UNIT,
+	0x01, IPAC_IDTAG_MACADDR,
+	0x01, IPAC_IDTAG_LOCATION1,
+	0x01, IPAC_IDTAG_LOCATION2,
+	0x01, IPAC_IDTAG_EQUIPVERS,
+	0x01, IPAC_IDTAG_SWVERSION,
+	0x01, IPAC_IDTAG_UNITNAME,
+	0x01, IPAC_IDTAG_SERNR,
+};
+
+static const char *idtag_names[] = {
+	[IPAC_IDTAG_SERNR]	= "Serial_Number",
+	[IPAC_IDTAG_UNITNAME]	= "Unit_Name",
+	[IPAC_IDTAG_LOCATION1]	= "Location_1",
+	[IPAC_IDTAG_LOCATION2]	= "Location_2",
+	[IPAC_IDTAG_EQUIPVERS]	= "Equipment_Version",
+	[IPAC_IDTAG_SWVERSION]	= "Software_Version",
+	[IPAC_IDTAG_IPADDR]	= "IP_Address",
+	[IPAC_IDTAG_MACADDR]	= "MAC_Address",
+	[IPAC_IDTAG_UNIT]	= "Unit_ID",
+};
+
+const char *ipaccess_idtag_name(uint8_t tag)
+{
+	if (tag >= ARRAY_SIZE(idtag_names))
+		return "unknown";
+
+	return idtag_names[tag];
+}
+
+
 struct msgb *osmo_ipa_msg_alloc(int headroom)
 {
 	struct msgb *msg;
@@ -68,3 +124,151 @@ int osmo_ipa_msg_recv(int fd, struct msgb *msg)
 	msgb_put(msg, ret);
 	return ret;
 }
+
+int osmo_ipa_idtag_parse(struct tlv_parsed *dec, unsigned char *buf, int len)
+{
+	uint8_t t_len;
+	uint8_t t_tag;
+	uint8_t *cur = buf;
+
+	memset(dec, 0, sizeof(*dec));
+
+	while (len >= 2) {
+		len -= 2;
+		t_len = *cur++;
+		t_tag = *cur++;
+
+		if (t_len > len + 1) {
+			LOGP(DLMI, LOGL_ERROR, "The tag does not fit: %d\n", t_len);
+			return -EINVAL;
+		}
+
+		DEBUGPC(DLMI, "%s='%s' ", ipaccess_idtag_name(t_tag), cur);
+
+		dec->lv[t_tag].len = t_len;
+		dec->lv[t_tag].val = cur;
+
+		cur += t_len;
+		len -= t_len;
+	}
+	return 0;
+}
+
+int osmo_ipa_parse_unitid(const char *str, struct ipaccess_unit *unit_data)
+{
+	unsigned long ul;
+	char *endptr;
+	const char *nptr;
+
+	nptr = str;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->site_id = ul & 0xffff;
+
+	if (*endptr++ != '/')
+		return -EINVAL;
+
+	nptr = endptr;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->bts_id = ul & 0xffff;
+	if (*endptr++ != '/')
+		return -EINVAL;
+
+	nptr = endptr;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->trx_id = ul & 0xffff;
+
+	return 0;
+}
+
+static int ipaccess_send(int fd, const void *msg, size_t msglen)
+{
+	int ret;
+
+	ret = write(fd, msg, msglen);
+	if (ret < 0)
+		return ret;
+	if (ret < msglen) {
+		LOGP(DLINP, LOGL_ERROR, "ipaccess_send: short write\n");
+		return -EIO;
+	}
+	return ret;
+}
+
+int ipaccess_send_pong(int fd)
+{
+	return ipaccess_send(fd, ipa_pong_msg, sizeof(ipa_pong_msg));
+}
+
+int ipaccess_send_id_ack(int fd)
+{
+	return ipaccess_send(fd, ipa_id_ack_msg, sizeof(ipa_id_ack_msg));
+}
+
+int ipaccess_send_id_req(int fd)
+{
+	return ipaccess_send(fd, ipa_id_req_msg, sizeof(ipa_id_req_msg));
+}
+
+/* base handling of the ip.access protocol */
+int osmo_ipa_rcvmsg_base(struct msgb *msg, struct osmo_fd *bfd)
+{
+	int ipa_ccm = 0;
+	uint8_t msg_type = *(msg->l2h);
+	int ret = 0;
+
+	switch (msg_type) {
+	case IPAC_MSGT_PING:
+		ipa_ccm = 1;
+		ret = ipaccess_send_pong(bfd->fd);
+		break;
+	case IPAC_MSGT_PONG:
+		DEBUGP(DLMI, "PONG!\n");
+		ipa_ccm = 1;
+		break;
+	case IPAC_MSGT_ID_ACK:
+		DEBUGP(DLMI, "ID_ACK? -> ACK!\n");
+		ipa_ccm = 1;
+		ret = ipaccess_send_id_ack(bfd->fd);
+		break;
+	}
+	return ipa_ccm;
+}
+
+int ipaccess_parse_unitid(const char *str, struct ipaccess_unit *unit_data)
+{
+	unsigned long ul;
+	char *endptr;
+	const char *nptr;
+
+	nptr = str;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->site_id = ul & 0xffff;
+
+	if (*endptr++ != '/')
+		return -EINVAL;
+
+	nptr = endptr;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->bts_id = ul & 0xffff;
+
+	if (*endptr++ != '/')
+		return -EINVAL;
+
+	nptr = endptr;
+	ul = strtoul(nptr, &endptr, 10);
+	if (endptr <= nptr)
+		return -EINVAL;
+	unit_data->trx_id = ul & 0xffff;
+
+	return 0;
+}