netlink: add a basic netlink attribute parser of AF_NETLINK diag

* linux/netlink_diag.h (NETLINK_DIAG_*): New enum.
* netlink_sock_diag.c: Include "xlat/netlink_diag_attrs.h".
(decode_netlink_diag_msg): Use decode_nlattr.
* xlat/netlink_diag_attrs.in: New file.

Co-authored-by: Fabien Siron <fabien.siron@epita.fr>

diff --git a/linux/netlink_diag.h b/linux/netlink_diag.h
index c56ffe6ed91b9c13064e212a6a043d41f1bea1fe..eda3ec39f085841eb2b67abe2c882b6bc87439de 100644 (file)
--- a/linux/netlink_diag.h
+++ b/linux/netlink_diag.h
@@ -23,6 +23,14 @@ struct netlink_diag_msg {
        uint32_t ndiag_cookie[2];
 };
 
+enum {
+       NETLINK_DIAG_MEMINFO,
+       NETLINK_DIAG_GROUPS,
+       NETLINK_DIAG_RX_RING,
+       NETLINK_DIAG_TX_RING,
+       NETLINK_DIAG_FLAGS,
+};
+
 #define NDIAG_SHOW_MEMINFO             0x00000001
 #define NDIAG_SHOW_GROUPS              0x00000002
 #define NDIAG_SHOW_RING_CFG            0x00000004 /* deprecated since 4.6 */

diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
index 8da2b1b671d26b2252a335e29b01246c0f6208f5..98a3fad2b5ab0e4d1b1569f4148f2b68f6bacc9c 100644 (file)
--- a/netlink_sock_diag.c
+++ b/netlink_sock_diag.c
@@ -45,6 +45,7 @@
 #include "xlat/tcp_states.h"
 #include "xlat/tcp_state_flags.h"
 
+#include "xlat/netlink_diag_attrs.h"
 #include "xlat/netlink_diag_show.h"
 #include "xlat/netlink_states.h"
 
@@ -200,7 +201,8 @@ decode_netlink_diag_msg(struct tcb *const tcp,
                        const kernel_ulong_t len)
 {
        struct netlink_diag_msg msg = { .ndiag_family = family };
-       const size_t offset = sizeof(msg.ndiag_family);
+       size_t offset = sizeof(msg.ndiag_family);
+       bool decode_nla = false;
 
        PRINT_FIELD_XVAL("{", msg, ndiag_family, addrfams, "AF_???");
        tprints(", ");
@@ -219,10 +221,18 @@ decode_netlink_diag_msg(struct tcb *const tcp,
                        PRINT_FIELD_U(", ", msg, ndiag_dst_group);
                        PRINT_FIELD_U(", ", msg, ndiag_ino);
                        PRINT_FIELD_COOKIE(", ", msg, ndiag_cookie);
+                       decode_nla = true;
                }
        } else
                tprints("...");
        tprints("}");
+
+       offset = NLA_ALIGN(sizeof(msg));
+       if (decode_nla && len > offset) {
+               tprints(", ");
+               decode_nlattr(tcp, addr + offset, len - offset,
+                             netlink_diag_attrs, "NETLINK_DIAG_???");
+       }
 }
 
 static void

diff --git a/xlat/netlink_diag_attrs.in b/xlat/netlink_diag_attrs.in
new file mode 100644 (file)
index 0000000..41e9a7a
--- /dev/null
+++ b/xlat/netlink_diag_attrs.in
@@ -0,0 +1,6 @@
+#unconditional
+NETLINK_DIAG_MEMINFO
+NETLINK_DIAG_GROUPS
+NETLINK_DIAG_RX_RING
+NETLINK_DIAG_TX_RING
+NETLINK_DIAG_FLAGS