netlink: introduce family specific payload decoders

* defs.h (netlink_decoder_t): New typedef.
(DECL_NETLINK): New macro.
(decode_netlink_sock_diag): New prototype.
* netlink.c (netlink_decoders): New array.
(decode_payload): Use it to invoke netlink family specific decoders.
* netlink_sock_diag.c: New file.
* Makefile.am (strace_SOURCES): Add it.

Co-authored-by: Fabien Siron <fabien.siron@epita.fr>
Co-authored-by: JingPiao Chen <chenjingpiao@gmail.com>

diff --git a/Makefile.am b/Makefile.am
index 80f8a3414f2cf5103def8a71f477082f1f0290bc..2266fa278c74f8a93b522ce12e7c31f1f0d5be36 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -172,6 +172,7 @@ strace_SOURCES =    \
        native_defs.h   \
        net.c           \
        netlink.c       \
+       netlink_sock_diag.c \
        nsfs.c          \
        nsfs.h          \
        nsig.h          \

diff --git a/defs.h b/defs.h
index 6449bce9879143f1a2b45a1180f57c7b9fb11d16..ddf80229053dccf3d10c139451de862c795d1c08 100644 (file)
--- a/defs.h
+++ b/defs.h
@@ -675,6 +675,17 @@ DECL_IOCTL(uffdio);
 
 extern int decode_sg_io_v4(struct tcb *, const kernel_ulong_t arg);
 
+struct nlmsghdr;
+
+typedef bool (*netlink_decoder_t)(struct tcb *, const struct nlmsghdr *,
+                                 kernel_ulong_t addr, kernel_ulong_t len);
+
+#define DECL_NETLINK(name)                                             \
+extern bool                                                            \
+decode_netlink_ ## name(struct tcb *, const struct nlmsghdr *,         \
+                       kernel_ulong_t addr, kernel_ulong_t len)
+DECL_NETLINK(sock_diag);
+
 extern int tv_nz(const struct timeval *);
 extern int tv_cmp(const struct timeval *, const struct timeval *);
 extern double tv_float(const struct timeval *);

diff --git a/netlink.c b/netlink.c
index 06144d5048f9745107d1a603b3bb41d4d96bfaf9..4bef9498aac2b52bedbe396aaba0c9f3e8689b9d 100644 (file)
--- a/netlink.c
+++ b/netlink.c
@@ -300,6 +300,10 @@ decode_nlmsgerr(struct tcb *const tcp,
        tprints("}");
 }
 
+static const netlink_decoder_t netlink_decoders[] = {
+       [NETLINK_SOCK_DIAG] = decode_netlink_sock_diag
+};
+
 static void
 decode_payload(struct tcb *const tcp,
               const int fd,
@@ -311,7 +315,15 @@ decode_payload(struct tcb *const tcp,
        if (nlmsghdr->nlmsg_type == NLMSG_ERROR) {
                decode_nlmsgerr(tcp, fd, family, addr, len);
                return;
-       } else if (nlmsghdr->nlmsg_type == NLMSG_DONE && len == sizeof(int)) {
+       }
+
+       if ((unsigned int) family < ARRAY_SIZE(netlink_decoders)
+           && netlink_decoders[family]
+           && netlink_decoders[family](tcp, nlmsghdr, addr, len)) {
+               return;
+       }
+
+       if (nlmsghdr->nlmsg_type == NLMSG_DONE && len == sizeof(int)) {
                int num;
 
                if (!umove_or_printaddr(tcp, addr, &num))

diff --git a/netlink_sock_diag.c b/netlink_sock_diag.c
new file mode 100644 (file)
index 0000000..29c09f3
--- /dev/null
+++ b/netlink_sock_diag.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
+ * Copyright (c) 2017 The strace developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "defs.h"
+
+static void
+decode_family(struct tcb *const tcp, const uint8_t family,
+             const kernel_ulong_t addr, const kernel_ulong_t len)
+{
+       tprints("{family=");
+       printxval(addrfams, family, "AF_???");
+       if (len > sizeof(family)) {
+               tprints(", ");
+               printstrn(tcp, addr + sizeof(family),
+                         len - sizeof(family));
+       }
+       tprints("}");
+}
+
+bool
+decode_netlink_sock_diag(struct tcb *const tcp,
+                        const struct nlmsghdr *const nlmsghdr,
+                        const kernel_ulong_t addr,
+                        const kernel_ulong_t len)
+{
+       uint8_t family;
+
+       if (!umove_or_printaddr(tcp, addr, &family))
+               decode_family(tcp, family, addr, len);
+
+       return true;
+}