From: Dmitry V. Levin <ldv@altlinux.org>
Date: Fri, 9 Jun 2017 23:06:42 +0000 (+0000)
Subject: netlink: introduce family specific payload decoders
X-Git-Tag: v4.18~91
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=09c4dac214f739726842a009f029cb26b58f21f0;p=strace

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 80f8a341..2266fa27 100644
--- 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 6449bce9..ddf80229 100644
--- 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 06144d50..4bef9498 100644
--- 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
index 00000000..29c09f3d
--- /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;
+}