1  /*
       2   * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
       3   * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
       4   * Copyright (c) 2016-2022 The strace developers.
       5   * All rights reserved.
       6   *
       7   * SPDX-License-Identifier: LGPL-2.1-or-later
       8   */
       9  
      10  #ifndef STRACE_NLATTR_H
      11  # define STRACE_NLATTR_H
      12  
      13  # include "xlat.h"
      14  
      15  struct decode_nla_xlat_opts {
      16  	const struct xlat *xlat;
      17  	const char *dflt;
      18  	enum xlat_style style;
      19  	const char *fn_str;
      20  	uint64_t (*process_fn)(uint64_t val);
      21  	size_t size;
      22  };
      23  
      24  /*
      25   * Used for IFLA_LINKINFO decoding.  Since there are no other indicators
      26   * regarding the nature of data except for previously provided string
      27   * in an IFLA_LINKINFO_KIND attribute, we have to store it in order to pass
      28   * between calls as an opaque data.
      29   */
      30  struct ifla_linkinfo_ctx {
      31  	char kind[64];
      32  	char slave_kind[64];
      33  };
      34  
      35  typedef bool (*nla_decoder_t)(struct tcb *, kernel_ulong_t addr,
      36  			      unsigned int len, const void *opaque_data);
      37  
      38  /**
      39   * The case of non-NULL decoders and zero size is handled in a special way:
      40   * the zeroth decoder is always called with nla_type being passed as opaque
      41   * data.
      42   */
      43  extern void
      44  decode_nlattr(struct tcb *,
      45  	      kernel_ulong_t addr,
      46  	      unsigned int len,
      47  	      const struct xlat *,
      48  	      const char *dflt,
      49  	      const nla_decoder_t *decoders,
      50  	      unsigned int size,
      51  	      const void *opaque_data);
      52  
      53  # define DECL_NLA(name)					\
      54  extern bool						\
      55  decode_nla_ ## name(struct tcb *, kernel_ulong_t addr,	\
      56  		    unsigned int len, const void *)	\
      57  /* End of DECL_NLA definition. */
      58  
      59  DECL_NLA(x8);
      60  DECL_NLA(x16);
      61  DECL_NLA(x32);
      62  DECL_NLA(x64);
      63  DECL_NLA(xint);
      64  DECL_NLA(u8);
      65  DECL_NLA(u16);
      66  DECL_NLA(u32);
      67  DECL_NLA(u64);
      68  DECL_NLA(s8);
      69  DECL_NLA(s16);
      70  DECL_NLA(s32);
      71  DECL_NLA(s64);
      72  DECL_NLA(be16);
      73  DECL_NLA(be64);
      74  DECL_NLA(xval);
      75  DECL_NLA(flags);
      76  DECL_NLA(str);
      77  DECL_NLA(strn);
      78  DECL_NLA(fd);
      79  DECL_NLA(uid);
      80  DECL_NLA(gid);
      81  DECL_NLA(clock_t);
      82  DECL_NLA(ifindex);
      83  DECL_NLA(ifla_af_spec);
      84  DECL_NLA(ether_proto);
      85  DECL_NLA(ip_proto);
      86  DECL_NLA(in_addr);
      87  DECL_NLA(in6_addr);
      88  DECL_NLA(lwt_encap_type);
      89  DECL_NLA(meminfo);
      90  DECL_NLA(rt_class);
      91  DECL_NLA(rt_proto);
      92  DECL_NLA(rtnl_link_stats64);
      93  DECL_NLA(tc_stats);
      94  
      95  # define NLA_HWADDR_FAMILY_OFFSET 1024
      96  
      97  /**
      98   * Print hardware (low-level, L2) address.
      99   * @param opaque_data Interpreted as integer value, not pointer
     100   */
     101  DECL_NLA(hwaddr);
     102  
     103  /** Non-standard decoder that accepts ARPHRD_* value as an argument */
     104  static inline bool
     105  decode_nla_hwaddr_family(struct tcb *const tcp,
     106  		const kernel_ulong_t addr,
     107  		const unsigned int len,
     108  		const unsigned int arphrd)
     109  {
     110  	return decode_nla_hwaddr(tcp, addr, len, (void *) (uintptr_t) (
     111  				 arphrd > NLA_HWADDR_FAMILY_OFFSET ? 0
     112  					: NLA_HWADDR_FAMILY_OFFSET | arphrd));
     113  }
     114  
     115  /** decode_nla_hwaddr wrapper that ignores opaque_data */
     116  static inline bool
     117  decode_nla_hwaddr_nofamily(struct tcb *const tcp,
     118  		const kernel_ulong_t addr,
     119  		const unsigned int len,
     120  		const void *const opaque_data)
     121  {
     122  	return decode_nla_hwaddr(tcp, addr, len, NULL);
     123  }
     124  
     125  /* Common handling for AF_SPEC-type decoders */
     126  
     127  struct af_spec_decoder_desc {
     128  	uint8_t af;
     129  	const struct xlat *xlat;
     130  	const char *dflt;
     131  	const nla_decoder_t *table;
     132  	size_t size;
     133  };
     134  
     135  /**
     136   * Non-standard decoder for handling AF_SPEC-type netlink attributes.
     137   *
     138   * @param af        Address family (AF_*), as passed to decoder in opaque_data
     139   *                  parameter through zero-sized decoder table decode_nlattr
     140   *                  hack.
     141   * @param descs     List of supported decoders.
     142   * @param desc_cnt  Number of items in descs.
     143   */
     144  extern void decode_nla_af_spec(struct tcb *const tcp,
     145  			       const kernel_ulong_t addr,
     146  			       const unsigned int len,
     147  			       uint8_t af,
     148  			       const struct af_spec_decoder_desc *descs,
     149  			       size_t desc_cnt);
     150  
     151  #endif /* !STRACE_NLATTR_H */