rtnl_route: decode rtmsg netlink attributes

* configure.ac (AC_CHECK_TYPES): Check for
rta_mfc_stats and rtvia structures in <linux/rtnetlink.h>.
* nlattr.c (decode_nla_ifindex): New function.
* nlattr.h (decode_nla_ifindex): New prototype.
* rtnl_route.c (decode_route_addr, decode_rta_metrics,
decode_rta_multipath, decode_rta_cacheinfo,
decode_rta_mfc_stats, decode_rtvia,
decode_rta_encap_type): New functions.
(rta_metrics_nla_decoders, rtmsg_nla_decoders): New arrays.
(decode_rtmsg): Use rtmsg_nla_decoders.
* xlat/lwtunnel_encap_types.in: New file.
* xlat/route_nexthop_flags.in: Likewise.
* xlat/rtnl_rta_metrics_attrs.in: Likewise.

Co-authored-by: Dmitry V. Levin <ldv@altlinux.org>

configure.ac

@@ -447,6 +447,11 @@ AC_CHECK_TYPES([struct dcbmsg],,, [#include <linux/dcbnl.h>])
 AC_CHECK_TYPES([struct ifaddrlblmsg],,, [#include <linux/if_addrlabel.h>])
 AC_CHECK_TYPES([struct netconfmsg],,, [#include <linux/netconf.h>])
 
+AC_CHECK_TYPES(m4_normalize([
+	struct rta_mfc_stats,
+	struct rtvia
+]),,, [#include <linux/rtnetlink.h>])
+
 AC_CHECK_TYPES([struct statfs], [
 	AC_CHECK_MEMBERS(m4_normalize([
 		struct statfs.f_frsize,

nlattr.c

@@ -204,6 +204,22 @@ decode_nla_meminfo(struct tcb *const tcp,
 	return true;
 }
 
+bool
+decode_nla_ifindex(struct tcb *const tcp,
+	       const kernel_ulong_t addr,
+	       const unsigned int len,
+	       const void *const opaque_data)
+{
+	uint32_t ifindex;
+
+	if (len < sizeof(ifindex))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &ifindex))
+		print_ifindex(ifindex);
+
+	return true;
+}
+
 #define DECODE_NLA_INTEGER(name, type, fmt)		\
 bool							\
 decode_nla_ ## name(struct tcb *const tcp,		\

nlattr.h

@@ -58,6 +58,7 @@ DECL_NLA(s32);
 DECL_NLA(s64);
 DECL_NLA(str);
 DECL_NLA(strn);
+DECL_NLA(ifindex);
 DECL_NLA(meminfo);
 
 #endif /* !STRACE_NLATTR_H */

rtnl_route.c

@@ -37,11 +37,224 @@
 #include <linux/rtnetlink.h>
 
 #include "xlat/ip_type_of_services.h"
+#include "xlat/lwtunnel_encap_types.h"
+#include "xlat/route_nexthop_flags.h"
 #include "xlat/routing_flags.h"
 #include "xlat/routing_protocols.h"
 #include "xlat/routing_table_ids.h"
 #include "xlat/routing_types.h"
 #include "xlat/rtnl_route_attrs.h"
+#include "xlat/rtnl_rta_metrics_attrs.h"
+
+static bool
+decode_route_addr(struct tcb *const tcp,
+		  const kernel_ulong_t addr,
+		  const unsigned int len,
+		  const void *const opaque_data)
+{
+	const struct rtmsg *const rtmsg = opaque_data;
+
+	decode_inet_addr(tcp, addr, len, rtmsg->rtm_family, NULL);
+
+	return true;
+}
+
+static const nla_decoder_t rta_metrics_nla_decoders[] = {
+	[RTAX_LOCK]		= decode_nla_u32,
+	[RTAX_MTU]		= decode_nla_u32,
+	[RTAX_WINDOW]		= decode_nla_u32,
+	[RTAX_RTT]		= decode_nla_u32,
+	[RTAX_RTTVAR]		= decode_nla_u32,
+	[RTAX_SSTHRESH]		= decode_nla_u32,
+	[RTAX_CWND]		= decode_nla_u32,
+	[RTAX_ADVMSS]		= decode_nla_u32,
+	[RTAX_REORDERING]	= decode_nla_u32,
+	[RTAX_HOPLIMIT]		= decode_nla_u32,
+	[RTAX_INITCWND]		= decode_nla_u32,
+	[RTAX_FEATURES]		= decode_nla_u32,
+	[RTAX_RTO_MIN]		= decode_nla_u32,
+	[RTAX_INITRWND]		= decode_nla_u32,
+	[RTAX_QUICKACK]		= decode_nla_u32,
+	[RTAX_CC_ALGO]		= decode_nla_str
+};
+
+static bool
+decode_rta_metrics(struct tcb *const tcp,
+		   const kernel_ulong_t addr,
+		   const unsigned int len,
+		   const void *const opaque_data)
+{
+	decode_nlattr(tcp, addr, len, rtnl_rta_metrics_attrs,
+		      "RTAX_???", rta_metrics_nla_decoders,
+		      ARRAY_SIZE(rta_metrics_nla_decoders), opaque_data);
+
+	return true;
+}
+
+static bool
+decode_rta_multipath(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const unsigned int len,
+		     const void *const opaque_data);
+
+static bool
+decode_rta_cacheinfo(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const unsigned int len,
+		     const void *const opaque_data)
+{
+	struct rta_cacheinfo ci;
+
+	if (len < sizeof(ci))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &ci)) {
+		PRINT_FIELD_U("{", ci, rta_clntref);
+		PRINT_FIELD_U(", ", ci, rta_lastuse);
+		PRINT_FIELD_U(", ", ci, rta_expires);
+		PRINT_FIELD_U(", ", ci, rta_error);
+		PRINT_FIELD_U(", ", ci, rta_used);
+		PRINT_FIELD_X(", ", ci, rta_id);
+		PRINT_FIELD_U(", ", ci, rta_ts);
+		PRINT_FIELD_U(", ", ci, rta_tsage);
+		tprints("}");
+	}
+
+	return true;
+}
+
+static bool
+decode_rta_mfc_stats(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const unsigned int len,
+		     const void *const opaque_data)
+{
+#ifdef HAVE_STRUCT_RTA_MFC_STATS
+	struct rta_mfc_stats mfcs;
+
+	if (len < sizeof(mfcs))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &mfcs)) {
+		PRINT_FIELD_U("{", mfcs, mfcs_packets);
+		PRINT_FIELD_U(", ", mfcs, mfcs_bytes);
+		PRINT_FIELD_U(", ", mfcs, mfcs_wrong_if);
+		tprints("}");
+	}
+
+	return true;
+#else
+	return false;
+#endif
+}
+
+static bool
+decode_rtvia(struct tcb *const tcp,
+	     const kernel_ulong_t addr,
+	     const unsigned int len,
+	     const void *const opaque_data)
+{
+#ifdef HAVE_STRUCT_RTVIA
+	struct rtvia via;
+
+	if (len < sizeof(via))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &via)) {
+		PRINT_FIELD_XVAL("{", via, rtvia_family, addrfams, "AF_???");
+
+		const unsigned int offset = offsetof(struct rtvia, rtvia_addr);
+
+		if (len > offset) {
+			tprints(", ");
+			decode_inet_addr(tcp, addr + offset, len - offset,
+					 via.rtvia_family, "rtvia_addr");
+		}
+		tprints("}");
+	}
+
+	return true;
+#else
+	return false;
+#endif
+}
+
+static bool
+decode_rta_encap_type(struct tcb *const tcp,
+		      const kernel_ulong_t addr,
+		      const unsigned int len,
+		      const void *const opaque_data)
+{
+	uint16_t type;
+
+	if (len < sizeof(type))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &type))
+		printxval(lwtunnel_encap_types, type, "LWTUNNEL_ENCAP_???");
+
+	return true;
+}
+
+static const nla_decoder_t rtmsg_nla_decoders[] = {
+	[RTA_DST]		= decode_route_addr,
+	[RTA_SRC]		= decode_route_addr,
+	[RTA_IIF]		= decode_nla_ifindex,
+	[RTA_OIF]		= decode_nla_ifindex,
+	[RTA_GATEWAY]		= decode_route_addr,
+	[RTA_PRIORITY]		= decode_nla_u32,
+	[RTA_PREFSRC]		= decode_route_addr,
+	[RTA_METRICS]		= decode_rta_metrics,
+	[RTA_MULTIPATH]		= decode_rta_multipath,
+	[RTA_PROTOINFO]		= decode_nla_u32,
+	[RTA_FLOW]		= decode_nla_u32,
+	[RTA_CACHEINFO]		= decode_rta_cacheinfo,
+	[RTA_SESSION]		= NULL, /* unused */
+	[RTA_MP_ALGO]		= decode_nla_u32,
+	[RTA_TABLE]		= decode_nla_u32,
+	[RTA_MARK]		= decode_nla_u32,
+	[RTA_MFC_STATS]		= decode_rta_mfc_stats,
+	[RTA_VIA]		= decode_rtvia,
+	[RTA_NEWDST]		= decode_route_addr,
+	[RTA_PREF]		= decode_nla_u8,
+	[RTA_ENCAP_TYPE]	= decode_rta_encap_type,
+	[RTA_ENCAP]		= NULL, /* unimplemented */
+	[RTA_EXPIRES]		= decode_nla_u64,
+	[RTA_PAD]		= NULL,
+	[RTA_UID]		= decode_nla_u32,
+	[RTA_TTL_PROPAGATE]	= decode_nla_u8
+};
+
+static bool
+decode_rta_multipath(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const unsigned int len,
+		     const void *const opaque_data)
+{
+	struct rtnexthop nh;
+
+	if (len < sizeof(nh))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &nh)) {
+		/* print the whole structure regardless of its rtnh_len */
+		PRINT_FIELD_U("{", nh, rtnh_len);
+		PRINT_FIELD_FLAGS(", ", nh, rtnh_flags,
+				  route_nexthop_flags, "RTNH_F_???");
+		PRINT_FIELD_U(", ", nh, rtnh_hops);
+		PRINT_FIELD_IFINDEX(", ", nh, rtnh_ifindex);
+		tprints("}");
+
+		const unsigned short rtnh_len =
+			len < nh.rtnh_len ? len : nh.rtnh_len;
+		const size_t offset = RTNH_ALIGN(sizeof(nh));
+		if (rtnh_len > offset) {
+			tprints(", ");
+			decode_nlattr(tcp, addr + offset, rtnh_len - offset,
+				      rtnl_route_attrs, "RTA_???",
+				      rtmsg_nla_decoders,
+				      ARRAY_SIZE(rtmsg_nla_decoders),
+				      opaque_data);
+		}
+	}
+
+	return true;
+}
 
 DECL_NETLINK_ROUTE_DECODER(decode_rtmsg)
 {
@@ -80,6 +293,8 @@ DECL_NETLINK_ROUTE_DECODER(decode_rtmsg)
 	if (decode_nla && len > offset) {
 		tprints(", ");
 		decode_nlattr(tcp, addr + offset, len - offset,
-			      rtnl_route_attrs, "RTA_???", NULL, 0, NULL);
+			      rtnl_route_attrs, "RTA_???",
+			      rtmsg_nla_decoders,
+			      ARRAY_SIZE(rtmsg_nla_decoders), &rtmsg);
 	}
 }

xlat/lwtunnel_encap_types.in

@@ -0,0 +1,7 @@
+LWTUNNEL_ENCAP_NONE	0
+LWTUNNEL_ENCAP_MPLS	1
+LWTUNNEL_ENCAP_IP	2
+LWTUNNEL_ENCAP_ILA	3
+LWTUNNEL_ENCAP_IP6	4
+LWTUNNEL_ENCAP_SEG6	5
+LWTUNNEL_ENCAP_BPF	6

xlat/route_nexthop_flags.in

@@ -0,0 +1,6 @@
+RTNH_F_DEAD
+RTNH_F_PERVASIVE
+RTNH_F_ONLINK
+RTNH_F_OFFLOAD
+RTNH_F_LINKDOWN
+RTNH_F_UNRESOLVED

xlat/rtnl_rta_metrics_attrs.in

@@ -0,0 +1,17 @@
+RTAX_UNSPEC	0
+RTAX_LOCK	1
+RTAX_MTU	2
+RTAX_WINDOW	3
+RTAX_RTT	4
+RTAX_RTTVAR	5
+RTAX_SSTHRESH	6
+RTAX_CWND	7
+RTAX_ADVMSS	8
+RTAX_REORDERING	9
+RTAX_HOPLIMIT	10
+RTAX_INITCWND	11
+RTAX_FEATURES	12
+RTAX_RTO_MIN	13
+RTAX_INITRWND	14
+RTAX_QUICKACK	15
+RTAX_CC_ALGO	16