Constify LLC/SNDCP parameters

That makes it easier to track side-effects while reading the code.

Related: OS#5349
Change-Id: I903f8a747a8d3b7f734dac7b0c12373ecbb90b11

5 files changed, 23 insertions, 22 deletions

diff --git a/include/osmocom/sgsn/gprs_llc.h b/include/osmocom/sgsn/gprs_llc.h
index 6cdb995be..7ba551054 100644
--- a/include/osmocom/sgsn/gprs_llc.h
+++ b/include/osmocom/sgsn/gprs_llc.h
@@ -271,7 +271,7 @@ static inline int gprs_llc_is_retransmit(uint16_t nu, uint16_t vur)
 }
 
 /* LLC low level functions */
-void gprs_llme_copy_key(struct sgsn_mm_ctx *mm, struct gprs_llc_llme *llme);
+void gprs_llme_copy_key(const struct sgsn_mm_ctx *mm, struct gprs_llc_llme *llme);
 
 /* parse a GPRS LLC header, also check for invalid frames */
 int gprs_llc_hdr_parse(struct gprs_llc_hdr_parsed *ghp,
diff --git a/include/osmocom/sgsn/gprs_sndcp.h b/include/osmocom/sgsn/gprs_sndcp.h
index 5334d92c0..ad192fe6f 100644
--- a/include/osmocom/sgsn/gprs_sndcp.h
+++ b/include/osmocom/sgsn/gprs_sndcp.h
@@ -68,7 +68,7 @@ int sndcp_sn_xid_req(struct gprs_llc_lle *lle, uint8_t nsapi);
  * Section 6.8 XID parameter negotiation) */
 int sndcp_sn_xid_ind(struct gprs_llc_xid_field *xid_field_indication,
 		     struct gprs_llc_xid_field *xid_field_response,
-		     struct gprs_llc_lle *lle);
+		     const struct gprs_llc_lle *lle);
 
 /* Process SNDCP-XID indication
  * (See also: TS 144 065, Section 6.8 XID parameter negotiation) */
@@ -77,6 +77,6 @@ int sndcp_sn_xid_conf(struct gprs_llc_xid_field *xid_field_conf,
 		      struct gprs_llc_lle *lle);
 
 /* Clean up all gprs_sndcp_entities related to llme (OS#4824) */
-void gprs_sndcp_sm_deactivate_ind_by_llme(struct gprs_llc_llme *llme);
+void gprs_sndcp_sm_deactivate_ind_by_llme(const struct gprs_llc_llme *llme);
 
 #endif	/* INT_SNDCP_H */
diff --git a/include/osmocom/sgsn/sgsn.h b/include/osmocom/sgsn/sgsn.h
index 1b34c2a5d..f0eda9833 100644
--- a/include/osmocom/sgsn/sgsn.h
+++ b/include/osmocom/sgsn/sgsn.h
@@ -182,7 +182,7 @@ int sgsn_mme_ran_info_req(struct sgsn_mme_ctx *mme, const struct bssgp_ran_infor
 /* Entry point for the SNSM-ACTIVATE.indication */
 int sndcp_sm_activate_ind(struct gprs_llc_lle *lle, uint8_t nsapi);
 /* Entry point for the SNSM-DEACTIVATE.indication */
-int sndcp_sm_deactivate_ind(struct gprs_llc_lle *lle, uint8_t nsapi);
+int sndcp_sm_deactivate_ind(const struct gprs_llc_lle *lle, uint8_t nsapi);
 /* Called by SNDCP when it has received/re-assembled a N-PDU */
 int sgsn_rx_sndcp_ud_ind(struct gprs_ra_id *ra_id, int32_t tlli, uint8_t nsapi,
 			 struct msgb *msg, uint32_t npdu_len, uint8_t *npdu);
diff --git a/src/sgsn/gprs_llc.c b/src/sgsn/gprs_llc.c
index f16f200c4..fda03191f 100644
--- a/src/sgsn/gprs_llc.c
+++ b/src/sgsn/gprs_llc.c
@@ -51,9 +51,9 @@ const struct value_string gprs_llc_llme_state_names[] = {
 };
 
 static struct gprs_llc_llme *llme_alloc(uint32_t tlli);
-static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg,
+static int gprs_llc_tx_xid(const struct gprs_llc_lle *lle, struct msgb *msg,
 			   int command);
-static int gprs_llc_tx_dm(struct gprs_llc_lle *lle);
+static int gprs_llc_tx_dm(const struct gprs_llc_lle *lle);
 static int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi,
 			 int command, enum gprs_llc_u_cmd u_cmd, int pf_bit);
 
@@ -212,7 +212,7 @@ static int gprs_llc_process_xid_ind(uint8_t *bytes_request,
 				    int bytes_request_len,
 				    uint8_t *bytes_response,
 				    int bytes_response_maxlen,
-				    struct gprs_llc_lle *lle)
+				    const struct gprs_llc_lle *lle)
 {
 	/* Note: This function computes the response that is sent back to the
 	 * MS when a mobile originated XID is received. The function is
@@ -288,7 +288,7 @@ static int gprs_llc_process_xid_ind(uint8_t *bytes_request,
 
 /* Dispatch XID indications and responses comming from the MS */
 static void rx_llc_xid(struct gprs_llc_lle *lle,
-		       struct gprs_llc_hdr_parsed *gph)
+		       const struct gprs_llc_hdr_parsed *gph)
 {
 	uint8_t response[1024];
 	int response_len;
@@ -681,7 +681,7 @@ int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command,
 }
 
 /* Send XID response to LLE */
-static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg,
+static int gprs_llc_tx_xid(const struct gprs_llc_lle *lle, struct msgb *msg,
 			   int command)
 {
 	/* copy identifiers from LLE to ensure lower layers can route */
@@ -692,7 +692,7 @@ static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg,
 	return gprs_llc_tx_u(msg, lle->sapi, command, GPRS_LLC_U_XID, 1);
 }
 
-static int gprs_llc_tx_dm(struct gprs_llc_lle *lle)
+static int gprs_llc_tx_dm(const struct gprs_llc_lle *lle)
 {
 	struct msgb *msg = msgb_alloc_headroom(4096, 1024, "LLC_DM");
 
@@ -705,7 +705,7 @@ static int gprs_llc_tx_dm(struct gprs_llc_lle *lle)
 }
 
 /* encrypt information field + FCS, if needed! */
-static int apply_gea(struct gprs_llc_lle *lle, uint16_t crypt_len, uint16_t nu,
+static int apply_gea(const struct gprs_llc_lle *lle, uint16_t crypt_len, uint16_t nu,
 		     uint32_t oc, uint8_t sapi, uint8_t *fcs, uint8_t *data)
 {
 	uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK];
@@ -1037,7 +1037,7 @@ int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv)
 }
 
 /* Propagate crypto parameters MM -> LLME */
-void gprs_llme_copy_key(struct sgsn_mm_ctx *mm, struct gprs_llc_llme *llme)
+void gprs_llme_copy_key(const struct sgsn_mm_ctx *mm, struct gprs_llc_llme *llme)
 {
 	if (!mm)
 		return;
diff --git a/src/sgsn/gprs_sndcp.c b/src/sgsn/gprs_sndcp.c
index 24262e4b7..fc454dbdd 100644
--- a/src/sgsn/gprs_sndcp.c
+++ b/src/sgsn/gprs_sndcp.c
@@ -66,7 +66,7 @@ static uint16_t calc_ip_csum(uint8_t *data, int len)
 }
 
 /* Calculate TCP/IP checksum */
-static uint16_t calc_tcpip_csum(const void *ctx, uint8_t *packet, int len)
+static uint16_t calc_tcpip_csum(const void *ctx, const uint8_t *packet, int len)
 {
 	uint8_t *buf;
 	uint16_t csum;
@@ -84,7 +84,7 @@ static uint16_t calc_tcpip_csum(const void *ctx, uint8_t *packet, int len)
 }
 
 /* Show some ip packet details */
-static void debug_ip_packet(uint8_t *data, int len, int dir, char *info)
+static void debug_ip_packet(const uint8_t *data, int len, int dir, const char *info)
 {
 	uint8_t tcp_flags;
 	char flags_debugmsg[256];
@@ -221,7 +221,8 @@ struct defrag_queue_entry {
 LLIST_HEAD(gprs_sndcp_entities);
 
 /* Check if any compression parameters are set in the sgsn configuration */
-static inline int any_pcomp_or_dcomp_active(struct sgsn_instance *sgsn) {
+static inline int any_pcomp_or_dcomp_active(const struct sgsn_instance *sgsn)
+{
 	if (sgsn->cfg.pcomp_rfc1144.active || sgsn->cfg.pcomp_rfc1144.passive ||
 	    sgsn->cfg.dcomp_v42bis.active || sgsn->cfg.dcomp_v42bis.passive)
 		return true;
@@ -260,7 +261,7 @@ static int defrag_enqueue(struct gprs_sndcp_entity *sne, uint8_t seg_nr,
 }
 
 /* return if we have all segments of this N-PDU */
-static int defrag_have_all_segments(struct gprs_sndcp_entity *sne)
+static int defrag_have_all_segments(const struct gprs_sndcp_entity *sne)
 {
 	uint32_t seg_needed = 0;
 	unsigned int i;
@@ -275,7 +276,7 @@ static int defrag_have_all_segments(struct gprs_sndcp_entity *sne)
 	return 0;
 }
 
-static struct defrag_queue_entry *defrag_get_seg(struct gprs_sndcp_entity *sne,
+static struct defrag_queue_entry *defrag_get_seg(const struct gprs_sndcp_entity *sne,
 						 uint32_t seg_nr)
 {
 	struct defrag_queue_entry *dqe;
@@ -522,7 +523,7 @@ int sndcp_sm_activate_ind(struct gprs_llc_lle *lle, uint8_t nsapi)
 }
 
 /* Entry point for the SNSM-DEACTIVATE.indication */
-int sndcp_sm_deactivate_ind(struct gprs_llc_lle *lle, uint8_t nsapi)
+int sndcp_sm_deactivate_ind(const struct gprs_llc_lle *lle, uint8_t nsapi)
 {
 	struct gprs_sndcp_entity *sne;
 
@@ -545,7 +546,7 @@ int sndcp_sm_deactivate_ind(struct gprs_llc_lle *lle, uint8_t nsapi)
 }
 
 /* Clean up all gprs_sndcp_entities related to llme (OS#4824) */
-void gprs_sndcp_sm_deactivate_ind_by_llme(struct gprs_llc_llme *llme)
+void gprs_sndcp_sm_deactivate_ind_by_llme(const struct gprs_llc_llme *llme)
 {
 	struct gprs_sndcp_entity *sne, *sne2;
 
@@ -1057,7 +1058,7 @@ int sndcp_sn_xid_req(struct gprs_llc_lle *lle, uint8_t nsapi)
 
 /* Handle header compression entites */
 static int handle_pcomp_entities(struct gprs_sndcp_comp_field *comp_field,
-				 struct gprs_llc_lle *lle)
+				 const struct gprs_llc_lle *lle)
 {
 	/* Note: This functions also transforms the comp_field into its
 	 * echo form (strips comp values, resets propose bit etc...)
@@ -1107,7 +1108,7 @@ static int handle_pcomp_entities(struct gprs_sndcp_comp_field *comp_field,
 
 /* Hanle data compression entites */
 static int handle_dcomp_entities(struct gprs_sndcp_comp_field *comp_field,
-				 struct gprs_llc_lle *lle)
+				 const struct gprs_llc_lle *lle)
 {
 	/* See note in handle_pcomp_entities() */
 
@@ -1149,7 +1150,7 @@ static int handle_dcomp_entities(struct gprs_sndcp_comp_field *comp_field,
  * (See also: TS 144 065, Section 6.8 XID parameter negotiation) */
 int sndcp_sn_xid_ind(struct gprs_llc_xid_field *xid_field_indication,
 		     struct gprs_llc_xid_field *xid_field_response,
-		     struct gprs_llc_lle *lle)
+		     const struct gprs_llc_lle *lle)
 {
 	/* Note: This function computes the SNDCP-XID response that is sent
 	 * back to the ms when a ms originated XID is received. The