[PATCH v3 13/16] netlink: introduce nla_decoder_t to parse netlink attribute data
JingPiao Chen
chenjingpiao at gmail.com
Mon Jun 19 01:15:37 UTC 2017
* nlattr.h (nla_decoder_t): New typedef.
(DECL_NLA): New macro.
(decode_nlattr): Add decoders, size and opaque_data argument.
* nlattr.c: (decode_nlattr_with_data): Likewise.
(decode_nla_*): New functions.
* netlink_sock_diag.c (decode_inet_diag_req_compat)
(decode_inet_diag_req_v2, decode_inet_diag_msg)
(decode_netlink_diag_msg, (decode_packet_diag_msg)
(decode_smc_diag_msg, decode_unix_diag_msg): Add decoders,
size and opaque_data arguments. All callers updated.
Co-authored-by: Fabien Siron <fabien.siron at epita.fr>
---
netlink_sock_diag.c | 21 ++++++++++++------
nlattr.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++----
nlattr.h | 27 +++++++++++++++++++++--
3 files changed, 98 insertions(+), 13 deletions(-)
diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
index f46c441..57c2439 100644
--- a/netlink_sock_diag.c
+++ b/netlink_sock_diag.c
@@ -149,7 +149,8 @@ decode_unix_diag_msg(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- unix_diag_attrs, "UNIX_DIAG_???");
+ unix_diag_attrs, "UNIX_DIAG_???",
+ NULL, 0, NULL);
}
}
@@ -238,7 +239,8 @@ decode_netlink_diag_msg(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- netlink_diag_attrs, "NETLINK_DIAG_???");
+ netlink_diag_attrs, "NETLINK_DIAG_???",
+ NULL, 0, NULL);
}
}
@@ -309,7 +311,8 @@ decode_packet_diag_msg(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- packet_diag_attrs, "PACKET_DIAG_???");
+ packet_diag_attrs, "PACKET_DIAG_???",
+ NULL, 0, NULL);
}
}
@@ -373,7 +376,8 @@ decode_inet_diag_req_compat(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- inet_diag_req_attrs, "INET_DIAG_REQ_???");
+ inet_diag_req_attrs, "INET_DIAG_REQ_???",
+ NULL, 0, NULL);
}
}
@@ -417,7 +421,8 @@ decode_inet_diag_req_v2(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- inet_diag_req_attrs, "INET_DIAG_REQ_???");
+ inet_diag_req_attrs, "INET_DIAG_REQ_???",
+ NULL, 0, NULL);
}
}
@@ -483,7 +488,8 @@ decode_inet_diag_msg(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- inet_diag_attrs, "INET_DIAG_???");
+ inet_diag_attrs, "INET_DIAG_???",
+ NULL, 0, NULL);
}
}
@@ -563,7 +569,8 @@ decode_smc_diag_msg(struct tcb *const tcp,
if (decode_nla && len > offset) {
tprints(", ");
decode_nlattr(tcp, addr + offset, len - offset,
- smc_diag_attrs, "SMC_DIAG_???");
+ smc_diag_attrs, "SMC_DIAG_???",
+ NULL, 0, NULL);
}
}
#endif
diff --git a/nlattr.c b/nlattr.c
index eaf7e39..daa8261 100644
--- a/nlattr.c
+++ b/nlattr.c
@@ -28,6 +28,7 @@
*/
#include "defs.h"
+#include "nlattr.h"
#include <linux/netlink.h>
@@ -66,7 +67,10 @@ decode_nlattr_with_data(struct tcb *tcp,
kernel_ulong_t addr,
kernel_ulong_t len,
const struct xlat *const table,
- const char *const dflt)
+ const char *const dflt,
+ const nla_decoder_t *decoders,
+ unsigned int size,
+ void *const opaque_data)
{
unsigned int nla_len = nla->nla_len > len ? len : nla->nla_len;
@@ -77,7 +81,13 @@ decode_nlattr_with_data(struct tcb *tcp,
if (nla_len > NLA_HDRLEN) {
tprints(", ");
- printstrn(tcp, addr + NLA_HDRLEN, nla_len - NLA_HDRLEN);
+ if (!decoders
+ || nla->nla_type >= size
+ || !decoders[nla->nla_type]
+ || !decoders[nla->nla_type](tcp, addr + NLA_HDRLEN,
+ nla_len - NLA_HDRLEN,
+ opaque_data))
+ printstrn(tcp, addr + NLA_HDRLEN, len - NLA_HDRLEN);
tprints("}");
}
}
@@ -87,7 +97,10 @@ decode_nlattr(struct tcb *const tcp,
kernel_ulong_t addr,
kernel_ulong_t len,
const struct xlat *const table,
- const char *const dflt)
+ const char *const dflt,
+ const nla_decoder_t *decoders,
+ unsigned int size,
+ void *const opaque_data)
{
struct nlattr nla;
bool print_array = false;
@@ -115,7 +128,8 @@ decode_nlattr(struct tcb *const tcp,
print_array = true;
}
- decode_nlattr_with_data(tcp, &nla, addr, len, table, dflt);
+ decode_nlattr_with_data(tcp, &nla, addr, len, table, dflt,
+ decoders, size, opaque_data);
if (!next_addr)
break;
@@ -129,3 +143,44 @@ decode_nlattr(struct tcb *const tcp,
tprints("]");
}
}
+
+bool
+decode_nla_str(struct tcb *tcp, kernel_ulong_t addr,
+ kernel_ulong_t len, void *const opaque_data)
+{
+ printstr(tcp, addr);
+
+ return true;
+}
+
+bool
+decode_nla_strn(struct tcb *tcp, kernel_ulong_t addr,
+ kernel_ulong_t len, void *const opaque_data)
+{
+ printstrn(tcp, addr, len);
+
+ return true;
+}
+
+#define DECODE_NLA_INTEGER(name, type, fmt) \
+bool \
+decode_nla_ ## name(struct tcb *tcp, kernel_ulong_t addr, \
+ kernel_ulong_t len, void *const opaque_data) \
+{ \
+ type num; \
+ \
+ if (len < sizeof(num)) \
+ return false; \
+ else if (!umove_or_printaddr(tcp, addr, &num)) \
+ tprintf(fmt, num); \
+ return true; \
+}
+
+DECODE_NLA_INTEGER(u8, uint8_t, "%" PRIu8)
+DECODE_NLA_INTEGER(u16, uint16_t, "%" PRIu16)
+DECODE_NLA_INTEGER(u32, uint32_t, "%" PRIu32)
+DECODE_NLA_INTEGER(u64, uint64_t, "%" PRIu64)
+DECODE_NLA_INTEGER(s8, int8_t, "%" PRId8)
+DECODE_NLA_INTEGER(s16, int16_t, "%" PRId16)
+DECODE_NLA_INTEGER(s32, int32_t, "%" PRId32)
+DECODE_NLA_INTEGER(s64, int64_t, "%" PRId64)
diff --git a/nlattr.h b/nlattr.h
index 6b94fc1..8501c4d 100644
--- a/nlattr.h
+++ b/nlattr.h
@@ -27,6 +27,29 @@
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+typedef bool (*nla_decoder_t)(struct tcb *, kernel_ulong_t addr,
+ kernel_ulong_t len, void *opaque_data);
extern void
-decode_nlattr(struct tcb *, kernel_ulong_t addr, kernel_ulong_t len,
- const struct xlat *, const char *);
+decode_nlattr(struct tcb *,
+ kernel_ulong_t addr,
+ kernel_ulong_t len,
+ const struct xlat *,
+ const char *,
+ const nla_decoder_t *,
+ unsigned int size,
+ void *);
+
+#define DECL_NLA(name) \
+extern bool \
+decode_nla_ ## name(struct tcb *, kernel_ulong_t addr, \
+ kernel_ulong_t len, void *)
+DECL_NLA(u8);
+DECL_NLA(u16);
+DECL_NLA(u32);
+DECL_NLA(u64);
+DECL_NLA(s8);
+DECL_NLA(s16);
+DECL_NLA(s32);
+DECL_NLA(s64);
+DECL_NLA(str);
+DECL_NLA(strn);
--
2.7.4
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