netlink: add a basic rtnetlink parser of link messages

* netlink_route.h: New file.
* rtnl_link.c: Likewise.
* Makefile.am (strace_SOURCES): Add them.
* defs.h (arp_hardware_types, iffflags): New xlat prototypes.
* netlink_route.c: Include "netlink_route.h"
and <linux/rtnetlink.h>.
(netlink_route_decoder_t): New typedef.
(route_decoders): New array.
(decode_netlink_route): Use it.

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

diff --git a/Makefile.am b/Makefile.am
index 23ce121f55da39cef924482df9cb10a2d9726a7f..7e7d3db6586c5aaae8cfdda6cfe590ef1284f2f1 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -194,6 +194,7 @@ strace_SOURCES =    \
        netlink_netlink_diag.c \
        netlink_packet_diag.c \
        netlink_route.c \
+       netlink_route.h \
        netlink_selinux.c \
        netlink_smc_diag.c \
        netlink_sock_diag.c \
@@ -246,6 +247,7 @@ strace_SOURCES =    \
        rt_sigframe.c   \
        rt_sigreturn.c  \
        rtc.c           \
+       rtnl_link.c     \
        sched.c         \
        sched_attr.h    \
        scsi.c          \

diff --git a/defs.h b/defs.h
index 5b09f2e3cbc744494fa5bfad5384587a21b30e5f..2efbfa3698019c4ef6f8921d952a5dbe84abd05b 100644 (file)
--- a/defs.h
+++ b/defs.h
@@ -284,11 +284,13 @@ struct tcb {
 #include "xlat.h"
 
 extern const struct xlat addrfams[];
+extern const struct xlat arp_hardware_types[];
 extern const struct xlat at_flags[];
 extern const struct xlat clocknames[];
 extern const struct xlat dirent_types[];
 extern const struct xlat ethernet_protocols[];
 extern const struct xlat evdev_abs[];
+extern const struct xlat iffflags[];
 extern const struct xlat inet_protocols[];
 extern const struct xlat msg_flags[];
 extern const struct xlat netlink_protocols[];

diff --git a/netlink_route.c b/netlink_route.c
index dc5a13f4b8363d84370725c1c454ac73da6d2fa3..f6d569ba888f08c448897cda1d05c35142e87b4a 100644 (file)
--- a/netlink_route.c
+++ b/netlink_route.c
@@ -29,6 +29,9 @@
 
 #include "defs.h"
 #include "netlink.h"
+#include "netlink_route.h"
+
+#include <linux/rtnetlink.h>
 
 #include "xlat/nl_route_types.h"
 
@@ -46,6 +49,15 @@ decode_family(struct tcb *const tcp, const uint8_t family,
        tprints("}");
 }
 
+typedef DECL_NETLINK_ROUTE_DECODER((*netlink_route_decoder_t));
+
+static const netlink_route_decoder_t route_decoders[] = {
+       [RTM_DELLINK - RTM_BASE] = decode_ifinfomsg,
+       [RTM_GETLINK - RTM_BASE] = decode_ifinfomsg,
+       [RTM_NEWLINK - RTM_BASE] = decode_ifinfomsg,
+       [RTM_SETLINK - RTM_BASE] = decode_ifinfomsg
+};
+
 bool
 decode_netlink_route(struct tcb *const tcp,
                     const struct nlmsghdr *const nlmsghdr,
@@ -57,8 +69,16 @@ decode_netlink_route(struct tcb *const tcp,
        if (nlmsghdr->nlmsg_type == NLMSG_DONE)
                return false;
 
-       if (!umove_or_printaddr(tcp, addr, &family))
-               decode_family(tcp, family, addr, len);
+       if (!umove_or_printaddr(tcp, addr, &family)) {
+               const unsigned int index = nlmsghdr->nlmsg_type - RTM_BASE;
+
+               if (index < ARRAY_SIZE(route_decoders)
+                   && route_decoders[index]) {
+                       route_decoders[index](tcp, nlmsghdr, family, addr, len);
+               } else {
+                       decode_family(tcp, family, addr, len);
+               }
+       }
 
        return true;
 }

diff --git a/netlink_route.h b/netlink_route.h
new file mode 100644 (file)
index 0000000..cc2b5c2
--- /dev/null
+++ b/netlink_route.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
+ * Copyright (c) 2016-2017 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.
+ */
+
+#ifndef STRACE_NETLINK_ROUTE_H
+#define STRACE_NETLINK_ROUTE_H
+
+#define DECL_NETLINK_ROUTE_DECODER(route_decode_name)  \
+void                                                   \
+route_decode_name(struct tcb *tcp,                     \
+                 const struct nlmsghdr *nlmsghdr,      \
+                 uint8_t family,                       \
+                 kernel_ulong_t addr,                  \
+                 unsigned int len)                     \
+/* End of DECL_NETLINK_ROUTE_DECODER definition. */
+
+extern DECL_NETLINK_ROUTE_DECODER(decode_ifinfomsg);
+
+#endif /* !STRACE_NETLINK_ROUTE_H */

diff --git a/rtnl_link.c b/rtnl_link.c
new file mode 100644 (file)
index 0000000..876baff
--- /dev/null
+++ b/rtnl_link.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
+ * Copyright (c) 2016-2017 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"
+#include "netlink_route.h"
+#include "print_fields.h"
+
+#include <linux/rtnetlink.h>
+
+DECL_NETLINK_ROUTE_DECODER(decode_ifinfomsg)
+{
+       struct ifinfomsg ifinfo = { .ifi_family = family };
+       const size_t offset = sizeof(ifinfo.ifi_family);
+
+       PRINT_FIELD_XVAL("{", ifinfo, ifi_family, addrfams, "AF_???");
+
+       tprints(", ");
+       if (len >= sizeof(ifinfo)) {
+               if (!umoven_or_printaddr(tcp, addr + offset,
+                                        sizeof(ifinfo) - offset,
+                                        (void *) &ifinfo + offset)) {
+                       PRINT_FIELD_XVAL("", ifinfo, ifi_type,
+                                        arp_hardware_types, "ARPHRD_???");
+                       PRINT_FIELD_IFINDEX(", ", ifinfo, ifi_index);
+                       PRINT_FIELD_FLAGS(", ", ifinfo, ifi_flags,
+                                         iffflags, "IFF_???");
+                       PRINT_FIELD_X(", ", ifinfo, ifi_change);
+               }
+       } else
+               tprints("...");
+       tprints("}");
+}