update/extend doxygen documentation

It's a pity that even with this patch we still are fare away from having
the whole API documented.  However, at least we have a more solid
foundation.  Updates not only extend the documentation, but also make
sure it is rendered properly in the doxygen HTML.

Change-Id: I1344bd1a6869fb00de7c1899a8db93bba9bafce3

62 files changed, 826 insertions, 150 deletions

diff --git a/src/bits.c b/src/bits.c
index 0c77b279..fe92f933 100644
--- a/src/bits.c
+++ b/src/bits.c
@@ -26,12 +26,11 @@
 
 /*! \addtogroup bits
  *  @{
- */
-
-/*! \file bits.c
  *  \brief Osmocom bit level support code
  */
 
+/*! \file bits.c */
+
 
 /*! \brief convert unpacked bits to packed bits, return length in bytes
  *  \param[out] out output buffer of packed bits
diff --git a/src/bitvec.c b/src/bitvec.c
index c895cffa..41e4f64c 100644
--- a/src/bitvec.c
+++ b/src/bitvec.c
@@ -24,12 +24,11 @@
 
 /*! \addtogroup bitvec
  *  @{
- */
-
-/*! \file bitvec.c
  *  \brief Osmocom bit vector abstraction
  */
 
+/*! \file bitvec.c */
+
 #include <errno.h>
 #include <stdint.h>
 #include <string.h>
diff --git a/src/conv.c b/src/conv.c
index 79b3a7c0..8e97e52e 100644
--- a/src/conv.c
+++ b/src/conv.c
@@ -24,11 +24,10 @@
 
 /*! \addtogroup conv
  *  @{
+ *  \brief Osmocom convolutional encoder and decoder
  */
 
-/*! \file conv.c
- * Osmocom convolutional encoder and decoder
- */
+/*! \file conv.c */
 #include "config.h"
 #ifdef HAVE_ALLOCA_H
 #include <alloca.h>
diff --git a/src/crcXXgen.c.tpl b/src/crcXXgen.c.tpl
index 7e45c111..1a69e852 100644
--- a/src/crcXXgen.c.tpl
+++ b/src/crcXXgen.c.tpl
@@ -24,6 +24,7 @@
 
 /*! \addtogroup crcgen
  *  @{
+ *  \brief Osmocom generic CRC routines
  */
 
 /*! \file crcXXgen.c
diff --git a/src/fsm.c b/src/fsm.c
index 5e744827..fbe22d72 100644
--- a/src/fsm.c
+++ b/src/fsm.c
@@ -29,9 +29,6 @@
 
 /*! \addtogroup fsm
  *  @{
- */
-
-/*! \file fsm.c
  *  \brief Finite State Machine abstraction
  *
  *  This is a generic C-language abstraction for implementing finite
@@ -84,9 +81,10 @@
  *
  *  In order to attach private state to the \ref osmo_fsm_inst, it
  *  offers an opaque priv pointer.
- *
  */
 
+/*! \file fsm.c */
+
 LLIST_HEAD(osmo_g_fsms);
 static bool fsm_log_addr = true;
 
diff --git a/src/gb/gprs_ns.c b/src/gb/gprs_ns.c
index 23c0be88..17933ed1 100644
--- a/src/gb/gprs_ns.c
+++ b/src/gb/gprs_ns.c
@@ -1648,4 +1648,4 @@ void gprs_ns_set_log_ss(int ss)
 	DNS = ss;
 }
 
-/*! }@ */
+/*! @} */
diff --git a/src/gsm/a5.c b/src/gsm/a5.c
index dbba0f20..23cbe0c9 100644
--- a/src/gsm/a5.c
+++ b/src/gsm/a5.c
@@ -26,13 +26,12 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-/*! \addtogroup a5
+/*! \addtogroup crypto
  *  @{
+ *  \brief Osmocom GSM/GPRS ciphering algorithm implementation
  */
 
-/*! \file gsm/a5.c
- *  \brief Osmocom GSM A5 ciphering algorithm implementation
- */
+/*! \file gsm/a5.c */
 
 #include <errno.h>
 #include <string.h>
diff --git a/src/gsm/abis_nm.c b/src/gsm/abis_nm.c
index 73759cbd..c9549027 100644
--- a/src/gsm/abis_nm.c
+++ b/src/gsm/abis_nm.c
@@ -22,6 +22,8 @@
 
 /*! \addtogroup oml
  *  @{
+ * \brief GSM Network Management (OML) messages on the A-bis interface
+ * 3GPP TS 12.21 version 8.0.0 Release 1999 / ETSI TS 100 623 V8.0.0
  */
 
 /*! \file abis_nm.c */
diff --git a/src/gsm/auth_comp128v1.c b/src/gsm/auth_comp128v1.c
index c40027ee..3b645d2a 100644
--- a/src/gsm/auth_comp128v1.c
+++ b/src/gsm/auth_comp128v1.c
@@ -24,6 +24,10 @@
 #include <osmocom/crypt/auth.h>
 #include <osmocom/gsm/comp128.h>
 
+/*! \addtogroup auth
+ *  @{
+ */
+
 static int c128v1_gen_vec(struct osmo_auth_vector *vec,
 			  struct osmo_sub_auth_data *aud,
 			  const uint8_t *_rand)
@@ -45,3 +49,5 @@ static __attribute__((constructor)) void on_dso_load_c128(void)
 {
 	osmo_auth_register(&c128v1_alg);
 }
+
+/*! @} */
diff --git a/src/gsm/auth_comp128v23.c b/src/gsm/auth_comp128v23.c
index 168f8865..b0900af2 100644
--- a/src/gsm/auth_comp128v23.c
+++ b/src/gsm/auth_comp128v23.c
@@ -27,6 +27,10 @@
 #include <osmocom/crypt/auth.h>
 #include <osmocom/gsm/comp128v23.h>
 
+/*! \addtogroup auth
+ *  @{
+ */
+
 static int c128v2_gen_vec(struct osmo_auth_vector *vec,
 			  struct osmo_sub_auth_data *aud,
 			  const uint8_t *_rand)
@@ -66,3 +70,5 @@ static __attribute__((constructor)) void on_dso_load_c128(void)
 	osmo_auth_register(&c128v2_alg);
 	osmo_auth_register(&c128v3_alg);
 }
+
+/*! @} */
diff --git a/src/gsm/auth_core.c b/src/gsm/auth_core.c
index 9ca5d93b..c9e403c5 100644
--- a/src/gsm/auth_core.c
+++ b/src/gsm/auth_core.c
@@ -32,10 +32,10 @@
 
 /*! \addtogroup auth
  *  @{
+ *  \brief GSM/GPRS/3G authentication core infrastructure
  */
 
-/* \file auth_core.c
- */
+/* \file auth_core.c */
 
 static LLIST_HEAD(osmo_auths);
 
diff --git a/src/gsm/auth_milenage.c b/src/gsm/auth_milenage.c
index c1331b5b..41e538d2 100644
--- a/src/gsm/auth_milenage.c
+++ b/src/gsm/auth_milenage.c
@@ -25,6 +25,10 @@
 #include "milenage/common.h"
 #include "milenage/milenage.h"
 
+/*! \addtogroup auth
+ *  @{
+ */
+
 static int milenage_gen_vec(struct osmo_auth_vector *vec,
 			    struct osmo_sub_auth_data *aud,
 			    const uint8_t *_rand)
@@ -160,3 +164,5 @@ static __attribute__((constructor)) void on_dso_load_milenage(void)
 {
 	osmo_auth_register(&milenage_alg);
 }
+
+/*! @} */
diff --git a/src/gsm/comp128.c b/src/gsm/comp128.c
index abb49179..cb3a3092 100644
--- a/src/gsm/comp128.c
+++ b/src/gsm/comp128.c
@@ -68,6 +68,14 @@
 #include <string.h>
 #include <stdint.h>
 
+/*! \addtogroup auth
+ *  @{
+ */
+
+/*! \file comp128.c
+ *  \brief COMP128 v1; common/old GSM Authentication Algorithm (A3/A8)
+ */
+
 /* The compression tables (just copied ...) */
 static const uint8_t table_0[512] = {
  102, 177, 186, 162,   2, 156, 112,  75,  55,  25,   8,  12, 251, 193, 246, 188,
@@ -184,6 +192,11 @@ _comp128_permutation(uint8_t *x, uint8_t *bits)
 		x[(i>>3)+16] |= bits[(i*17) & 127] << (7-(i&7));
 }
 
+/*! \brief Perform COMP128v1 algorithm
+ *  \param[in] ki Secret Key K(i) of subscriber
+ *  \param[in] rand Random Challenge
+ *  \param[out] sres user-supplied buffer for storing computed SRES value
+ *  \param[out] kc user-supplied buffer for storing computed Kc value */
 void
 comp128v1(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
@@ -228,8 +241,16 @@ comp128v1(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 	kc[7] = 0;
 }
 
+
+/*! \brief Perform COMP128v1 algorithm
+ *  \param[in] ki Secret Key K(i) of subscriber
+ *  \param[in] rand Random Challenge
+ *  \param[out] sres user-supplied buffer for storing computed SRES value
+ *  \param[out] kc user-supplied buffer for storing computed Kc value */
 void
 comp128(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
     comp128v1(ki, rand, sres, kc);
 }
+
+/*! @} */
diff --git a/src/gsm/comp128v23.c b/src/gsm/comp128v23.c
index e21b718e..bfb4a0ee 100644
--- a/src/gsm/comp128v23.c
+++ b/src/gsm/comp128v23.c
@@ -28,6 +28,14 @@
 #include <stdint.h>
 #include <string.h>
 
+/*! \addtogroup auth
+ *  @{
+ */
+
+/*! \file comp128v23.c
+ *  \brief COMP128 v2 / v3; Common Algorithm used for GSM Authentication (A3/A8)
+ */
+
 static const uint8_t table0[256] = {
 	197, 235, 60, 151, 98, 96, 3, 100, 248, 118, 42, 117, 172, 211, 181, 203, 61,
 	126, 156, 87, 149, 224, 55, 132, 186, 63, 238, 255, 85, 83, 152, 33, 160,
@@ -101,6 +109,12 @@ _comp128v23_internal(uint8_t *output, const uint8_t *kxor, const uint8_t *rand)
 	}
 }
 
+/*! \brief Perform COMP128v3 algorithm
+ *  \param[in] ki Secret Key K(i) of subscriber
+ *  \param[in] rand Random Challenge
+ *  \param[out] sres user-supplied buffer for storing computed SRES value
+ *  \param[out] kc user-supplied buffer for storing computed Kc value
+ *  \returns 0 */
 int
 comp128v3(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
@@ -147,6 +161,12 @@ comp128v3(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 	return 0;
 }
 
+/*! \brief Perform COMP128v2 algorithm
+ *  \param[in] ki Secret Key K(i) of subscriber
+ *  \param[in] rand Random Challenge
+ *  \param[out] sres user-supplied buffer for storing computed SRES value
+ *  \param[out] kc user-supplied buffer for storing computed Kc value
+ *  \returns 0 */
 int
 comp128v2(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
@@ -155,3 +175,5 @@ comp128v2(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 	kc[6] &= 0xfc;
 	return r;
 }
+
+/*! @} */
diff --git a/src/gsm/gan.c b/src/gsm/gan.c
index 0bcaa175..1d98b38b 100644
--- a/src/gsm/gan.c
+++ b/src/gsm/gan.c
@@ -21,6 +21,10 @@
 
 #include <osmocom/gsm/protocol/gsm_44_318.h>
 
+/*! \file gan.c
+ *  \brief Generic Access Network (GAN) / UMA according to TS 44.318
+ */
+
 
 const struct value_string gan_msgt_vals[] = {
 	{ GA_MT_RC_DISCOVERY_REQUEST,	"GA-RC DISCOVERY REQUEST" },
diff --git a/src/gsm/gea.c b/src/gsm/gea.c
index b8f6768a..8d026a29 100644
--- a/src/gsm/gea.c
+++ b/src/gsm/gea.c
@@ -30,6 +30,13 @@
 #include <stdint.h>
 #include <string.h>
 
+/*! \addtogroup crypto
+ *  @{
+ */
+
+/*! \file gsm/gea.c */
+
+
 /*! \brief Performs the GEA4 algorithm as in 3GPP TS 55.226 V9.0.0
  *  \param[in,out] out Buffer for gamma for encrypted/decrypted
  *  \param[in] len Length of out, in bytes
@@ -58,3 +65,5 @@ int gea3(uint8_t *out, uint16_t len, uint8_t *kc, uint32_t iv,
 	osmo_c4(ck, kc);
 	return gea4(out, len, ck, iv, direction);
 }
+
+/*! @} */
diff --git a/src/gsm/gprs_cipher_core.c b/src/gsm/gprs_cipher_core.c
index da6e0a83..a0cf1851 100644
--- a/src/gsm/gprs_cipher_core.c
+++ b/src/gsm/gprs_cipher_core.c
@@ -29,6 +29,10 @@
 
 #include <osmocom/crypt/gprs_cipher.h>
 
+/*! \addtogroup crypto
+ *  @{
+ */
+
 static LLIST_HEAD(gprs_ciphers);
 
 static struct gprs_cipher_impl *selected_ciphers[_GPRS_ALGO_NUM];
@@ -125,3 +129,4 @@ uint32_t gprs_cipher_gen_input_i(uint32_t iov_i, uint32_t lfn, uint32_t oc)
 {
 	return iov_i + lfn + oc;
 }
+/*! @} */
diff --git a/src/gsm/gprs_gea.c b/src/gsm/gprs_gea.c
index 8ff16484..836ee68c 100644
--- a/src/gsm/gprs_gea.c
+++ b/src/gsm/gprs_gea.c
@@ -27,6 +27,10 @@
 
 #include <stdint.h>
 
+/*! \addtogroup crypto
+ *  @{
+ */
+
 static struct gprs_cipher_impl gea3_impl = {
 	.algo = GPRS_ALGO_GEA3,
 	.name = "GEA3 (libosmogsm built-in)",
@@ -46,3 +50,5 @@ static __attribute__((constructor)) void on_dso_load_gea(void)
 	gprs_cipher_register(&gea3_impl);
 	gprs_cipher_register(&gea4_impl);
 }
+
+/*! @} */
diff --git a/src/gsm/gprs_rlc.c b/src/gsm/gprs_rlc.c
index a4053ef6..d1247be6 100644
--- a/src/gsm/gprs_rlc.c
+++ b/src/gsm/gprs_rlc.c
@@ -5,6 +5,10 @@
 #include <osmocom/coding/gsm0503_coding.h>
 #include <osmocom/gprs/protocol/gsm_04_60.h>
 
+/*! \file gsm/gprs_rlc.c
+ *  \brief helper functions for (E)GPRS RLC according to 3GPP TS 44.060
+ */
+
 #define EGPRS_CPS_TYPE1_TBL_SZ		29
 #define EGPRS_CPS_TYPE2_TBL_SZ		8
 #define EGPRS_CPS_TYPE3_TBL_SZ		16
diff --git a/src/gsm/gsm0341.c b/src/gsm/gsm0341.c
index 1c14d3ed..2592b54e 100644
--- a/src/gsm/gsm0341.c
+++ b/src/gsm/gsm0341.c
@@ -27,6 +27,22 @@
 #include <osmocom/core/talloc.h>
 #include <osmocom/gsm/protocol/gsm_03_41.h>
 
+/*! \addtogroup sms
+ *  @{
+ */
+
+/*! \brief Encode a 3GPP TS 03.41 SMS-CB message
+ *  \param[in] ctx talloc allocation context
+ *  \param[in] geo_scope Geographic Scope
+ *  \param[in] msg_code Message Code
+ *  \param[in] update Is this an update?
+ *  \param[in] msg_id Message ID
+ *  \param[in] dcs Data Coding Scheme
+ *  \param[in] page_total Total number of pages
+ *  \param[in] page_cur Current Page (up to \a page_total)
+ *  \param[in] data Message data (copied 1:1)
+ *  \param[in] len Length of \a data in bytes (up to 88)
+ *  \returns callee-allocated TS 03.41 message with encoded data */
 struct gsm341_ms_message *
 gsm0341_build_msg(void *ctx, uint8_t geo_scope, uint8_t msg_code,
 		  uint8_t update, uint16_t msg_id, uint8_t dcs,
@@ -57,3 +73,5 @@ gsm0341_build_msg(void *ctx, uint8_t geo_scope, uint8_t msg_code,
 
 	return cbmsg;
 }
+
+/*! @} */
diff --git a/src/gsm/gsm0411_smc.c b/src/gsm/gsm0411_smc.c
index 4c083659..03016b92 100644
--- a/src/gsm/gsm0411_smc.c
+++ b/src/gsm/gsm0411_smc.c
@@ -60,6 +60,11 @@
 #include <osmocom/gsm/gsm0411_smc.h>
 #include <osmocom/gsm/protocol/gsm_04_08.h>
 
+/*! \addtogroup sms
+ *  @{
+ *  \brief Point-to-Point (PP) Short Message Service (SMS) as per TS 04.11
+ */
+
 static void cp_timer_expired(void *data);
 
 #define MAX_SMS_RETRY 2
@@ -569,3 +574,5 @@ int gsm411_smc_recv(struct gsm411_smc_inst *inst, int msg_type,
 
 	return rc;
 }
+
+/*! @} */
diff --git a/src/gsm/gsm0411_smr.c b/src/gsm/gsm0411_smr.c
index eb8aec0d..d120f2df 100644
--- a/src/gsm/gsm0411_smr.c
+++ b/src/gsm/gsm0411_smr.c
@@ -62,6 +62,10 @@
 
 #define SMR_LOG_STR "SMR(%" PRIu64 ") "
 
+/*! \addtogroup sms
+ *  @{
+ */
+
 static void rp_timer_expired(void *data);
 
 /* init a new instance */
@@ -484,3 +488,5 @@ int gsm411_smr_recv(struct gsm411_smr_inst *inst, int msg_type,
 
 	return rc;
 }
+
+/*! @} */
diff --git a/src/gsm/gsm0411_utils.c b/src/gsm/gsm0411_utils.c
index b84c9f25..543775cc 100644
--- a/src/gsm/gsm0411_utils.c
+++ b/src/gsm/gsm0411_utils.c
@@ -38,16 +38,24 @@
 #include <osmocom/gsm/protocol/gsm_03_40.h>
 #include <osmocom/gsm/protocol/gsm_04_11.h>
 
+/*! \addtogroup sms
+ *  @{
+ */
+
 #define GSM411_ALLOC_SIZE	1024
 #define GSM411_ALLOC_HEADROOM	128
 
+/*! \brief Allocate a message buffer for use as TS 04.11 message
+ *  \returns allocated message buffer */
 struct msgb *gsm411_msgb_alloc(void)
 {
 	return msgb_alloc_headroom(GSM411_ALLOC_SIZE, GSM411_ALLOC_HEADROOM,
 				   "GSM 04.11");
 }
 
-/* Turn int into semi-octet representation: 98 => 0x89 */
+/*! \brief Turn int into semi-octet representation: 98 => 0x89
+ *  \param[in] integer value representing decimal number 0..99
+ *  \returns BSC encoded as nibbles, swapped */
 uint8_t gsm411_bcdify(uint8_t value)
 {
 	uint8_t ret;
@@ -58,7 +66,9 @@ uint8_t gsm411_bcdify(uint8_t value)
 	return ret;
 }
 
-/* Turn semi-octet representation into int: 0x89 => 98 */
+/*! \brief Turn semi-octet representation into int: 0x89 => 98
+ *  \param[in] value byte containing two BCD nibbles in revere order
+ *  \returns integer representing decoded, re-ordered nibbles */
 uint8_t gsm411_unbcdify(uint8_t value)
 {
 	uint8_t ret;
@@ -73,7 +83,9 @@ uint8_t gsm411_unbcdify(uint8_t value)
 	return ret;
 }
 
-/* Generate 03.40 TP-SCTS */
+/*! \brief Generate 03.40 TP-SCTS
+ *  \param[out] scts Caller-provided buffer to store SCTS (7 octets)
+ *  \param[in] time to encode */
 void gsm340_gen_scts(uint8_t *scts, time_t time)
 {
 	struct tm *tm = gmtime(&time);
@@ -92,7 +104,9 @@ void gsm340_gen_scts(uint8_t *scts, time_t time)
 #endif
 }
 
-/* Decode 03.40 TP-SCTS (into utc/gmt timestamp) */
+/*! \brief Decode 03.40 TP-SCTS (into utc/gmt timestamp)
+ *  \param[in] scts SMS Center Time Stamp
+ *  \return time in UTC time_t format */
 time_t gsm340_scts(uint8_t *scts)
 {
 	struct tm tm;
@@ -190,7 +204,10 @@ static unsigned long gsm340_vp_relative_semioctet(uint8_t *sms_vp)
 	return minutes;
 }
 
-/* decode validity period. return minutes */
+/*! \brief decode validity period. return minutes
+ *  \param[in] sms_vpf Validity Period Format in 03.40 encoding
+ *  \param[in] sms_vp Validity Period Information Element
+ *  \returns validity period in minutes */
 unsigned long gsm340_validity_period(uint8_t sms_vpf, uint8_t *sms_vp)
 {
 	uint8_t fi; /* functionality indicator */
@@ -228,7 +245,9 @@ unsigned long gsm340_validity_period(uint8_t sms_vpf, uint8_t *sms_vp)
 	}
 }
 
-/* determine coding alphabet dependent on GSM 03.38 Section 4 DCS */
+/*! \brief determine coding alphabet dependent on GSM 03.38 Section 4 DCS
+ *  \param[in] dcs Data Coding Scheme in 03.38 encoding
+ *  \returns libosmogsm internal enum \ref sms_alphabet */
 enum sms_alphabet gsm338_get_sms_alphabet(uint8_t dcs)
 {
 	uint8_t cgbits = dcs >> 4;
@@ -266,7 +285,13 @@ enum sms_alphabet gsm338_get_sms_alphabet(uint8_t dcs)
 	return alpha;
 }
 
-/* generate a TPDU address field compliant with 03.40 sec. 9.1.2.5 */
+/*! \brief generate a TPDU address field compliant with 03.40 sec. 9.1.2.5 
+ *  \param[out] oa caller-provided output buffer
+ *  \param[in] oa_len caller-specified length of \a oa in bytes
+ *  \param[in] type GSM340_TYPE_*
+ *  \param[in] plan Numbering Plan
+ *  \param[in] number string containing number
+ *  \reurns number of bytes of \a oa that have been used */
 int gsm340_gen_oa(uint8_t *oa, unsigned int oa_len, uint8_t type,
 	uint8_t plan, const char *number)
 {
@@ -296,7 +321,11 @@ int gsm340_gen_oa(uint8_t *oa, unsigned int oa_len, uint8_t type,
 	return len_in_bytes;
 }
 
-/* Prefix msg with a RP header */
+/*! \brief Prefix \ref msgb with a RP header
+ *  \param msg Message Buffer containing message
+ *  \param[in] rp_msg_type RP Message Type