Some messages have one or two length-value information elements. The is
no IE type included in the message. These information elements are
mandatory, so their actual IE type is known. The improved parse_tlv()
function allows to parse zero, one, or two length-value elements.
(Andreas Eversberg)
diff --git a/include/openbsc/tlv.h b/include/openbsc/tlv.h
index 453f1d0..ae88e6e 100644
--- a/include/openbsc/tlv.h
+++ b/include/openbsc/tlv.h
@@ -6,12 +6,21 @@
#include <openbsc/msgb.h>
+#define LV_GROSS_LEN(x) (x+1)
#define TLV_GROSS_LEN(x) (x+2)
#define TLV16_GROSS_LEN(x) ((2*x)+2)
#define TL16V_GROSS_LEN(x) (x+3)
/* TLV generation */
+static inline u_int8_t *lv_put(u_int8_t *buf, u_int8_t len,
+ const u_int8_t *val)
+{
+ *buf++ = len;
+ memcpy(buf, val, len);
+ return buf + len;
+}
+
static inline u_int8_t *tlv_put(u_int8_t *buf, u_int8_t tag, u_int8_t len,
const u_int8_t *val)
{
@@ -53,6 +62,12 @@
return tl16v_put(buf, tag, len, val);
}
+static inline u_int8_t *v_put(u_int8_t *buf, u_int8_t val)
+{
+ *buf++ = val;
+ return buf;
+}
+
static inline u_int8_t *tv_put(u_int8_t *buf, u_int8_t tag,
u_int8_t val)
{
@@ -70,6 +85,12 @@
return buf;
}
+static inline u_int8_t *msgb_lv_put(struct msgb *msg, u_int8_t len, const u_int8_t *val)
+{
+ u_int8_t *buf = msgb_put(msg, LV_GROSS_LEN(len));
+ return lv_put(buf, len, val);
+}
+
static inline u_int8_t *msgb_tlv_put(struct msgb *msg, u_int8_t tag, u_int8_t len, const u_int8_t *val)
{
u_int8_t *buf = msgb_put(msg, TLV_GROSS_LEN(len));
@@ -82,6 +103,12 @@
return tv_put(buf, tag, val);
}
+static inline u_int8_t *msgb_v_put(struct msgb *msg, u_int8_t val)
+{
+ u_int8_t *buf = msgb_put(msg, 1);
+ return v_put(buf, val);
+}
+
static inline u_int8_t *msgb_tv16_put(struct msgb *msg, u_int8_t tag, u_int16_t val)
{
u_int8_t *buf = msgb_put(msg, 3);
@@ -135,7 +162,7 @@
};
int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def,
- const u_int8_t *buf, int buf_len);
+ const u_int8_t *buf, int buf_len, u_int8_t lv_tag, u_int8_t lv_tag2);
#define TLVP_PRESENT(x, y) ((x)->lv[y].val)
#define TLVP_LEN(x, y) (x)->lv[y].len
diff --git a/src/abis_nm.c b/src/abis_nm.c
index 6909f78..0107c29 100644
--- a/src/abis_nm.c
+++ b/src/abis_nm.c
@@ -365,7 +365,7 @@
int abis_nm_tlv_parse(struct tlv_parsed *tp, const u_int8_t *buf, int len)
{
- return tlv_parse(tp, &nm_att_tlvdef, buf, len);
+ return tlv_parse(tp, &nm_att_tlvdef, buf, len, 0, 0);
}
static int is_in_arr(enum abis_nm_msgtype mt, const enum abis_nm_msgtype *arr, int size)
diff --git a/src/abis_rsl.c b/src/abis_rsl.c
index e7f953e..753a666 100644
--- a/src/abis_rsl.c
+++ b/src/abis_rsl.c
@@ -112,7 +112,8 @@
[0xfc] = { TLV_TYPE_TV },
},
};
-#define rsl_tlv_parse(dec, buf, len) tlv_parse(dec, &rsl_att_tlvdef, buf, len)
+#define rsl_tlv_parse(dec, buf, len) \
+ tlv_parse(dec, &rsl_att_tlvdef, buf, len, 0, 0)
static u_int8_t mdisc_by_msgtype(u_int8_t msg_type)
{
diff --git a/src/gsm_04_08.c b/src/gsm_04_08.c
index ad7bba6..849ef48 100644
--- a/src/gsm_04_08.c
+++ b/src/gsm_04_08.c
@@ -1119,7 +1119,7 @@
call->local_lchan = msg->lchan;
call->transaction_id = gh->proto_discr & 0xf0;
- tlv_parse(&tp, &rsl_att_tlvdef, gh->data, payload_len);
+ tlv_parse(&tp, &rsl_att_tlvdef, gh->data, payload_len, 0, 0);
if (!TLVP_PRESENT(&tp, GSM48_IE_CALLED_BCD))
goto err;
diff --git a/src/tlv_parser.c b/src/tlv_parser.c
index fe6d289..e835f95 100644
--- a/src/tlv_parser.c
+++ b/src/tlv_parser.c
@@ -13,16 +13,47 @@
return 0;
}
+/* dec: output: a caller-allocated pointer to a struct tlv_parsed,
+ * def: input: a structure defining the valid TLV tags / configurations
+ * buf: input: the input data buffer to be parsed
+ * buf_len: input: the length of the input data buffer
+ * lv_tag: input: an initial LV tag at the start of the buffer
+ * lv_tag2: input: a second initial LV tag following lv_tag
+ */
int tlv_parse(struct tlv_parsed *dec, const struct tlv_definition *def,
- const u_int8_t *buf, int buf_len)
+ const u_int8_t *buf, int buf_len, u_int8_t lv_tag,
+ u_int8_t lv_tag2)
{
u_int8_t tag, len = 1;
- const u_int8_t *pos;
+ const u_int8_t *pos = buf;
int num_parsed = 0;
memset(dec, 0, sizeof(*dec));
- for (pos = buf; pos < buf+buf_len; pos += len) {
+ if (lv_tag) {
+ if (pos > buf + buf_len)
+ return -1;
+ dec->lv[lv_tag].val = pos+1;
+ dec->lv[lv_tag].len = *pos;
+ len = dec->lv[lv_tag].len + 1;
+ if (pos + len > buf + buf_len)
+ return -2;
+ num_parsed++;
+ pos += len;
+ }
+ if (lv_tag2) {
+ if (pos > buf + buf_len)
+ return -1;
+ dec->lv[lv_tag2].val = pos+1;
+ dec->lv[lv_tag2].len = *pos;
+ len = dec->lv[lv_tag2].len + 1;
+ if (pos + len > buf + buf_len)
+ return -2;
+ num_parsed++;
+ pos += len;
+ }
+
+ for (; pos < buf+buf_len; pos += len) {
tag = *pos;
/* FIXME: use tables for knwon IEI */
switch (def->def[tag].type) {