src/plugins/lb/lb_plugin_doc.md

/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
  Copyright (c) 2001, 2002, 2003 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef included_clib_elf_h
#define included_clib_elf_h

#include <vppinfra/format.h>
#include <vppinfra/hash.h>
#include <vppinfra/vec.h>
#include <vppinfra/byte_order.h>

#define foreach_elf_file_class \
  _ (CLASS_NONE) _ (32BIT) _ (64BIT)

#define foreach_elf_data_encoding		\
  _ (ENCODING_NONE)				\
  _ (TWOS_COMPLEMENT_LITTLE_ENDIAN)		\
  _ (TWOS_COMPLEMENT_BIG_ENDIAN)

#define ELF_VERSION_NONE (0)
#define ELF_VERSION_CURRENT (1)

#define foreach_elf_abi				\
  _ (SYSV, 0)					\
  _ (HPUX, 1)					\
  _ (NETBSD, 2)					\
  _ (LINUX, 3)					\
  _ (SOLARIS, 6)				\
  _ (AIX, 7)					\
  _ (IRIX, 8)					\
  _ (FREEBSD, 9)				\
  _ (COMPAQ_TRU64, 10)				\
  _ (MODESTO, 11)				\
  _ (OPENBSD, 12)				\
  _ (ARM, 97)					\
  _ (STANDALONE, 255)

/* Legal values for type (object file type).  */
#define foreach_elf_file_type			\
  _ (NONE, 0)					\
  _ (RELOC, 1)					\
  _ (EXEC, 2)					\
  _ (SHARED, 3)					\
  _ (CORE, 4)					\
  _ (OS_SPECIFIC_LO, 0xfe00)			\
  _ (OS_SPECIFIC_HI, 0xfeff)			\
  _ (ARCH_SPECIFIC_LO, 0xff00)			\
  _ (ARCH_SPECIFIC_HI, 0xffff)

/* Legal values for architecture.  */
#define foreach_elf_architecture					\
  _ (NONE, 0)			/* No machine */			\
  _ (M32, 1)			/* AT&T WE 32100 */			\
  _ (SPARC, 2)			/* SUN SPARC */				\
  _ (386, 3)			/* Intel 80386 */			\
  _ (68K, 4)			/* Motorola m68k family */		\
  _ (88K, 5)			/* Motorola m88k family */		\
  _ (860, 7)			/* Intel 80860 */			\
  _ (MIPS, 8)			/* MIPS R3000 big-endian */		\
  _ (S370, 9)			/* IBM System/370 */			\
  _ (MIPS_RS3_LE, 10)		/* MIPS R3000 little-endian */		\
  _ (PARISC, 15)		/* HPPA */				\
  _ (VPP500, 17)		/* Fujitsu VPP500 */			\
  _ (SPARC32PLUS, 18)		/* Sun's "v8plus" */			\
  _ (960, 19)			/* Intel 80960 */			\
  _ (PPC, 20)			/* PowerPC */				\
  _ (PPC64, 21)			/* PowerPC 64-bit */			\
  _ (S390, 22)			/* IBM S390 */				\
  _ (V800, 36)			/* NEC V800 series */			\
  _ (FR20, 37)			/* Fujitsu FR20 */			\
  _ (RH32, 38)			/* TRW RH-32 */				\
  _ (RCE, 39)			/* Motorola RCE */			\
  _ (ARM, 40)			/* ARM */				\
  _ (FAKE_ALPHA, 41)		/* Digital Alpha */			\
  _ (SH, 42)			/* Hitachi SH */			\
  _ (SPARCV9, 43)		/* SPARC v9 64-bit */			\
  _ (TRICORE, 44)		/* Siemens Tricore */			\
  _ (ARC, 45)			/* Argonaut RISC Core */		\
  _ (H8_300, 46)		/* Hitachi H8/300 */			\
  _ (H8_300H, 47)		/* Hitachi H8/300H */			\
  _ (H8S, 48)			/* Hitachi H8S */			\
  _ (H8_500, 49)		/* Hitachi H8/500 */			\
  _ (IA_64, 50)			/* Intel Merced */			\
  _ (MIPS_X, 51)		/* Stanford MIPS-X */			\
  _ (COLDFIRE, 52)		/* Motorola Coldfire */			\
  _ (68HC12, 53)		/* Motorola M68HC12 */			\
  _ (MMA, 54)			/* Fujitsu MMA Multimedia Accel. */	\
  _ (PCP, 55)			/* Siemens PCP */			\
  _ (NCPU, 56)			/* Sony nCPU embedded RISC */		\
  _ (NDR1, 57)			/* Denso NDR1 microprocessor */		\
  _ (STARCORE, 58)		/* Motorola Start*Core processor */	\
  _ (ME16, 59)			/* Toyota ME16 processor */		\
  _ (ST100, 60)			/* STMicroelectronic ST100  */		\
  _ (TINYJ, 61)			/* Advanced Logic Corp. Tinyj */	\
  _ (X86_64, 62)		/* AMD x86-64 architecture */		\
  _ (PDSP, 63)			/* Sony DSP Processor */		\
  _ (FX66, 66)			/* Siemens FX66 microcontroller */	\
  _ (ST9PLUS, 67)		/* STMicroelectronics ST9+ 8/16 mc */	\
  _ (ST7, 68)			/* STmicroelectronics ST7 8 bit mc */	\
  _ (68HC16, 69)		/* Motorola MC68HC16 */			\
  _ (68HC11, 70)		/* Motorola MC68HC11 */			\
  _ (68HC08, 71)		/* Motorola MC68HC08 */			\
  _ (68HC05, 72)		/* Motorola MC68HC05 */			\
  _ (SVX, 73)			/* Silicon Graphics SVx */		\
  _ (ST19, 74)			/* STMicroelectronics ST19 8 bit mc */	\
  _ (VAX, 75)			/* Digital VAX */			\
  _ (CRIS, 76)			/* Axis 32-bit embedded proc. */	\
  _ (JAVELIN, 77)		/* Infineon 32-bit embedded proc. */	\
  _ (FIREPATH, 78)		/* Element 14 64-bit DSP Processor */	\
  _ (ZSP, 79)			/* LSI Logic 16-bit DSP Processor */	\
  _ (MMIX, 80)			/* Knuth's 64-bit processor */		\
  _ (HUANY, 81)			/* Harvard machine-independent */	\
  _ (PRISM, 82)			/* SiTera Prism */			\
  _ (AVR, 83)			/* Atmel AVR 8-bit microcontroller */	\
  _ (FR30, 84)			/* Fujitsu FR30 */			\
  _ (D10V, 85)			/* Mitsubishi D10V */			\
  _ (D30V, 86)			/* Mitsubishi D30V */			\
  _ (V850, 87)			/* NEC v850 */				\
  _ (M32R, 88)			/* Mitsubishi M32R */			\
  _ (MN10300, 89)		/* Matsushita MN10300 */		\
  _ (MN10200, 90)		/* Matsushita MN10200 */		\
  _ (PJ, 91)			/* picoJava */				\
  _ (OPENRISC, 92)		/* OpenRISC 32-bit processor */		\
  _ (ARC_A5, 93)		/* ARC Cores Tangent-A5 */		\
  _ (XTENSA, 94)		/* Tensilica Xtensa Architecture */	\
  _ (ALPHA, 0x9026)

#define _(f) ELF_##f,

typedef enum
{
  foreach_elf_file_class ELF_N_FILE_CLASS,
} elf_file_class_t;

typedef enum
{
  foreach_elf_data_encoding ELF_N_DATA_ENCODING,
} elf_data_encoding_t;

#undef _

#define _(f,i) ELF_##f = i,

typedef enum
{
  foreach_elf_abi
} elf_abi_t;

typedef enum
{
  foreach_elf_file_type
} elf_file_type_t;

#undef _

typedef enum
{
#define _(f,i) ELF_ARCH_##f = i,
  foreach_elf_architecture
#undef _
} elf_architecture_t;

typedef struct
{
  /* 0x7f ELF */
  u8 magic[4];

  elf_file_class_t file_class:8;
  elf_data_encoding_t data_encoding:8;
  u8 file_version_ident;
  elf_abi_t abi:8;
  u8 abi_version;

  u8 pad[7];

  elf_file_type_t file_type:16;
  elf_architecture_t architecture:16;

  u32 file_version;
} elf_first_header_t;

/* 32/64 bit file header following basic file header. */
#define foreach_elf32_file_header		\
  _ (u32, entry_point)				\
  _ (u32, segment_header_file_offset)		\
  _ (u32, section_header_file_offset)		\
  _ (u32, flags)				\
  _ (u16, n_bytes_this_header)			\
  _ (u16, segment_header_size)			\
  _ (u16, segment_header_count)			\
  _ (u16, section_header_size)			\
  _ (u16, section_header_count)			\
  _ (u16, section_header_string_table_index)

#define foreach_elf64_file_header		\
  _ (u64, entry_point)				\
  _ (u64, segment_header_file_offset)		\
  _ (u64, section_header_file_offset)		\
  _ (u32, flags)				\
  _ (u16, n_bytes_this_header)			\
  _ (u16, segment_header_size)			\
  _ (u16, segment_header_count)			\
  _ (u16, section_header_size)			\
  _ (u16, section_header_count)			\
  _ (u16, section_header_string_table_index)

/* Section header.  */
#define foreach_elf32_section_header		\
  _ (u32, name)					\
  _ (u32, type)					\
  _ (u32, flags)				\
  _ (u32, exec_address)				\
  _ (u32, file_offset)				\
  _ (u32, file_size)				\
  _ (u32, link)					\
  _ (u32, additional_info)			\
  _ (u32, align)				\
  _ (u32, entry_size)

#define foreach_elf64_section_header		\
  _ (u32, name)					\
  _ (u32, type)					\
  _ (u64, flags)				\
  _ (u64, exec_address)				\
  _ (u64, file_offset)				\
  _ (u64, file_size)				\
  _ (u32, link)					\
  _ (u32, additional_info)			\
  _ (u64, align)				\
  _ (u64, entry_size)

/* Program segment header.  */
#define foreach_elf32_segment_header		\
  _ (u32, type)					\
  _ (u32, file_offset)				\
  _ (u32, virtual_address)			\
  _ (u32, physical_address)			\
  _ (u32, file_size)				\
  _ (u32, memory_size)				\
  _ (u32, flags)				\
  _ (u32, align)

#define foreach_elf64_segment_header		\
  _ (u32, type)					\
  _ (u32, flags)				\
  _ (u64, file_offset)				\
  _ (u64, virtual_address)			\
  _ (u64, physical_address)			\
  _ (u64, file_size)				\
  _ (u64, memory_size)				\
  _ (u64, align)

/* Symbol table.  */
#define foreach_elf32_symbol_header		\
  _ (u32, name)					\
  _ (u32, value)				\
  _ (u32, size)					\
  /* binding upper 4 bits; type lower 4 bits */	\
  _ (u8, binding_and_type)			\
  _ (u8, visibility)				\
  _ (u16, section_index)

#define foreach_elf64_symbol_header		\
  _ (u32, name)					\
  _ (u8, binding_and_type)			\
  _ (u8, visibility)				\
  _ (u16, section_index)			\
  _ (u64, value)				\
  _ (u64, size)

#define _(t,f) t f;

typedef struct
{
foreach_elf32_file_header} elf32_file_header_t;

typedef struct
{
foreach_elf64_file_header} elf64_file_header_t;

typedef struct
{
foreach_elf32_section_header} elf32_section_header_t;

typedef struct
{
foreach_elf64_section_header} elf64_section_header_t;

typedef struct
{
foreach_elf32_segment_header} elf32_segment_header_t;

typedef struct
{
foreach_elf64_segment_header} elf64_segment_header_t;

typedef struct
{
foreach_elf32_symbol_header} elf32_symbol_t;

typedef struct
{
foreach_elf64_symbol_header} elf64_symbol_t;
#undef _

/* Special section names.  */
#define foreach_elf_symbol_reserved_section_index			\
  _ (ABSOLUTE, 0xfff1)		/* Associated symbol is absolute */	\
  _ (COMMON, 0xfff2)		/* Associated symbol is common */	\
  _ (XINDEX, 0xffff)		/* Index is in extra table.  */

#define ELF_SYMBOL_SECTION_RESERVED_LO 0xff00
#define ELF_SYMBOL_SECTION_RESERVED_HI 0xffff
#define ELF_SYMBOL_SECTION_ARCH_SPECIFIC_LO 0xff00
#define ELF_SYMBOL_SECTION_ARCH_SPECIFIC_HI 0xff1f
#define ELF_SYMBOL_SECTION_OS_SPECIFIC_LO 0xff20
#define ELF_SYMBOL_SECTION_OS_SPECIFIC_HI 0xff3f

/* Section types. */
#define foreach_elf_section_type					\
  _ (UNUSED, 0)								\
  _ (PROGRAM_DATA, 1)							\
  _ (SYMBOL_TABLE, 2)							\
  _ (STRING_TABLE, 3)							\
  _ (RELOCATION_ADD, 4)							\
  _ (SYMBOL_TABLE_HASH, 5)						\
  _ (DYNAMIC, 6)		/* Dynamic linking information */	\
  _ (NOTE, 7)			/* Notes */				\
  _ (NO_BITS, 8)		/* Program space with no data (bss) */	\
  _ (RELOCATION, 9)		/* Relocation entries, no addends */	\
  _ (DYNAMIC_SYMBOL_TABLE, 11)	/* Dynamic linker symbol table */	\
  _ (INIT_ARRAY, 14)		/* Array of constructors */		\
  _ (FINI_ARRAY, 15)		/* Array of destructors */		\
  _ (PREINIT_ARRAY, 16)		/* Array of pre-constructors */		\
  _ (GROUP, 17)			/* Section group */			\
  _ (SYMTAB_SHNDX, 18)		/* Extended section indices */		\
  _ (OS_SPECIFIC_LO, 0x60000000) /* Start OS-specific */		\
  _ (GNU_LIBLIST, 0x6ffffff7)	/* Prelink library list */		\
  _ (CHECKSUM, 0x6ffffff8)	/* Checksum for DSO content.  */	\
  _ (SUNW_MOVE, 0x6ffffffa)						\
  _ (SUNW_COMDAT, 0x6ffffffb)						\
  _ (SUNW_SYMINFO, 0x6ffffffc)						\
  _ (GNU_VERDEF, 0x6ffffffd)	/* Version definition section.  */	\
  _ (GNU_VERNEED, 0x6ffffffe) /* Version needs section.  */		\
  _ (GNU_VERSYM, 0x6fffffff)	/* Version symbol table.  */		\
  _ (ARCH_SPECIFIC_LO, 0x70000000) /* Start of processor-specific */	\
  _ (ARCH_SPECIFIC_HI, 0x7fffffff) /* End of processor-specific */	\
  _ (APP_SPECIFIC_LO, 0x80000000) /* Start of application-specific */	\
  _ (APP_SPECIFIC_HI, 0x8fffffff)	/* End of application-specific */

/* Section flags. */
#define foreach_elf_section_flag		\
  _ (WRITE, 0)					\
  _ (ALLOC, 1)					\
  _ (EXEC, 2)					\
  _ (MERGE, 3)					\
  _ (STRING_TABLE, 5)				\
  _ (INFO_LINK, 6)				\
  _ (PRESERVE_LINK_ORDER, 7)			\
  _ (OS_NON_CONFORMING, 8)			\
  _ (GROUP, 9)					\
  _ (TLS, 10)					\
  _ (OS_SPECIFIC_LO, 20)			\
  _ (OS_SPECIFIC_HI, 27)			\
  _ (ARCH_SPECIFIC_LO, 28)			\
  _ (ARCH_SPECIFIC_HI, 31)

typedef enum
{
#define _(f,i) ELF_SECTION_##f = i,
  foreach_elf_section_type
#undef _
    ELF_SECTION_OS_SPECIFIC_HI = 0x6fffffff,
} elf_section_type_t;

typedef enum
{
#define _(f,i) ELF_SECTION_FLAG_BIT_##f = i,
  foreach_elf_section_flag
#undef _
} elf_section_flag_bit_t;

typedef enum
{
#define _(f,i) ELF_SECTION_FLAG_##f = 1 << ELF_SECTION_FLAG_BIT_##f,
  foreach_elf_section_flag
#undef _
} elf_section_flag_t;

/* Symbol bindings (upper 4 bits of binding_and_type). */
#define foreach_elf_symbol_binding					\
  _ (LOCAL, 0)			/* Local symbol */			\
  _ (GLOBAL, 1)			/* Global symbol */			\
  _ (WEAK, 2)			/* Weak symbol */			\
  _ (OS_SPECIFIC_LO, 10)	/* Start of OS-specific */		\
  _ (OS_SPECIFIC_HI, 12)	/* End of OS-specific */		\
  _ (ARCH_SPECIFIC_LO, 13)	/* Start of processor-specific */	\
  _ (ARCH_SPECIFIC_HI, 15)	/* End of processor-specific */

/* Symbol types (lower 4 bits of binding_and_type). */
#define foreach_elf_symbol_type						\
  _ (NONE, 0)								\
  _ (DATA, 1)			/* Symbol is a data object */		\
  _ (CODE, 2)			/* Symbol is a code object */		\
  _ (SECTION, 3)		/* Symbol associated with a section */	\
  _ (FILE, 4)			/* Symbol's name is file name */	\
  _ (COMMON, 5)			/* Symbol is a common data object */	\
  _ (TLS, 6)			/* Symbol is thread-local data */	\
  _ (OS_SPECIFIC_LO, 10)	/* Start of OS-specific */		\
  _ (OS_SPECIFIC_HI, 12)	/* End of OS-specific */		\
  _ (ARCH_SPECIFIC_LO, 13)	/* Start of processor-specific */	\
  _ (ARCH_SPECIFIC_HI, 15)	/* End of processor-specific */

/* Symbol visibility. */
#define foreach_elf_symbol_visibility					\
  _ (DEFAULT, 0)		/* Default symbol visibility rules */	\
  _ (INTERNAL, 1)		/* Processor specific hidden class */	\
  _ (HIDDEN, 2)			/* Unavailable in other modules */	\
  _ (PROTECTED, 3)		/* Not preemptible, not exported */

/* The syminfo section if available contains additional
   information about every dynamic symbol.  */
typedef struct
{
  u16 bound_to;
  u16 flags;
} elf_symbol_info_t;

/* Possible values for bound_to.  */
#define foreach_elf_symbol_info_bound_to			\
  _ (SELF, 0xffff)		/* Symbol bound to self */	\
  _ (PARENT, 0xfffe)		/* Symbol bound to parent */	\
  _ (RESERVED_LO, 0xff00)					\
  _ (RESERVED_HI, 0xffff)

/* Symbol info flags. */
#define foreach_elf_symbol_info_flags					\
  _ (DIRECT)			/* Direct bound symbol */		\
  _ (PASS_THRU)			/* Pass-thru symbol for translator */	\
  _ (COPY)			/* Symbol is a copy-reloc */		\
  _ (LAZY_LOAD)			/* Symbol bound to object to be lazy loaded */

/* Relocation table entry with/without addend. */
typedef struct
{
  u32 address;
  u32 symbol_and_type;		/* high 24 symbol, low 8 type. */
  i32 addend[0];
} elf32_relocation_t;

typedef struct
{
  u64 address;
  u64 symbol_and_type;		/* high 32 symbol, low 32 type. */
  i64 addend[0];
} elf64_relocation_t;

typedef struct
{
  u64 address;
  u64 symbol_and_type;
  u64 addend;
} elf_relocation_with_addend_t;

#define elf_relocation_next(r,type)					\
  ((void *) ((r) + 1)							\
   + ((type) == ELF_SECTION_RELOCATION_ADD ? sizeof ((r)->addend[0]) : 0))

/* Segment type. */
#define foreach_elf_segment_type					\
  _ (UNUSED, 0)								\
  _ (LOAD, 1)			/* Loadable program segment */		\
  _ (DYNAMIC, 2)		/* Dynamic linking information */	\
  _ (INTERP, 3)			/* Program interpreter */		\
  _ (NOTE, 4)			/* Auxiliary information */		\
  _ (SEGMENT_TABLE, 6)		/* Entry for header table itself */	\
  _ (TLS, 7)			/* Thread-local storage segment */	\
  _ (OS_SPECIFIC_LO, 0x60000000) /* Start of OS-specific */		\
  _ (GNU_EH_FRAME, 0x6474e550)	/* GCC .eh_frame_hdr segment */		\
  _ (GNU_STACK, 0x6474e551)	/* Indicates stack executability */	\
  _ (GNU_RELRO, 0x6474e552)	/* Read-only after relocation */	\
  _ (SUNW_BSS, 0x6ffffffa)	/* Sun specific BSS */			\
  _ (SUNW_STACK, 0x6ffffffb)	/* Sun specific stack */		\
  _ (OS_SPECIFIC_HI, 0x6fffffff) /* End of OS-specific */		\
  _ (ARCH_SPECIFIC_LO, 0x70000000) /* Start of processor-specific */	\
  _ (ARCH_SPECIFIC_HI, 0x7fffffff)	/* End of processor-specific */

/* Segment flags. */
#define foreach_elf_segment_flag		\
  _ (EXEC, 0)					\
  _ (WRITE, 1)					\
  _ (READ, 2)					\
  _ (OS_SPECIFIC_LO, 20)			\
  _ (OS_SPECIFIC_HI, 27)			\
  _ (ARCH_SPECIFIC_LO, 28)			\
  _ (ARCH_SPECIFIC_HI, 31)

typedef enum
{
#define _(f,i) ELF_SEGMENT_##f = i,
  foreach_elf_segment_type
#undef _
} elf_segment_type_t;

typedef enum
{
#define _(f,i) ELF_SEGMENT_FLAG_BIT_##f = i,
  foreach_elf_segment_flag
#undef _
} elf_segment_flag_bit_t;

typedef enum
{
#define _(f,i) ELF_SEGMENT_FLAG_##f = 1 << ELF_SEGMENT_FLAG_BIT_##f,
  foreach_elf_segment_flag
#undef _
} elf_segment_flag_t;

#define foreach_elf32_dynamic_entry_header	\
  _ (u32, type)					\
  _ (u32, data)

#define foreach_elf64_dynamic_entry_header	\
  _ (u64, type)					\
  _ (u64, data)

#define _(t,f) t f;

typedef struct
{
foreach_elf32_dynamic_entry_header} elf32_dynamic_entry_t;

typedef struct
{
foreach_elf64_dynamic_entry_header} elf64_dynamic_entry_t;

#undef _

#define foreach_elf_dynamic_entry_type					\
  _ (END, 0)			/* Marks end of dynamic section */	\
  _ (NEEDED_LIBRARY, 1)		/* Name of needed library */		\
  _ (PLT_RELOCATION_SIZE, 2)	/* Size in bytes of PLT relocs */	\
  _ (PLT_GOT, 3)		/* Processor defined value */		\
  _ (SYMBOL_HASH, 4)		/* Address of symbol hash table */	\
  _ (STRING_TABLE, 5)		/* Address of string table */		\
  _ (SYMBOL_TABLE, 6)		/* Address of symbol table */		\
  _ (RELA_ADDRESS, 7)		/* Address of Rela relocs */		\
  _ (RELA_SIZE, 8)		/* Total size of Rela relocs */		\
  _ (RELA_ENTRY_SIZE, 9)	/* Size of one Rela reloc */		\
  _ (STRING_TABLE_SIZE, 10)	/* Size of string table */		\
  _ (SYMBOL_TABLE_ENTRY_SIZE, 11) /* Size of one symbol table entry */	\
  _ (INIT_FUNCTION, 12)		/* Address of init function */		\
  _ (FINI_FUNCTION, 13)		/* Address of termination function */	\
  _ (SONAME, 14)		/* Name of shared object */		\
  _ (RPATH, 15)			/* Library search path (deprecated) */	\
  _ (SYMBOLIC, 16)		/* Start symbol search here */		\
  _ (REL, 17)			/* Address of Rel relocs */		\
  _ (RELSZ, 18)			/* Total size of Rel relocs */		\
  _ (RELENT, 19)		/* Size of one Rel reloc */		\
  _ (PLT_RELOCATION_TYPE, 20)	/* Type of reloc in PLT */		\
  _ (DEBUG, 21)			/* For debugging; unspecified */	\
  _ (TEXTREL, 22)		/* Reloc might modify .text */		\
  _ (PLT_RELOCATION_ADDRESS, 23) /* Address of PLT relocs */		\
  _ (BIND_NOW, 24)		/* Process relocations of object */	\
  _ (INIT_ARRAY, 25)		/* Array with addresses of init fct */	\
  _ (FINI_ARRAY, 26)		/* Array with addresses of fini fct */	\
  _ (INIT_ARRAYSZ, 27)		/* Size in bytes of DT_INIT_ARRAY */	\
  _ (FINI_ARRAYSZ, 28)		/* Size in bytes of DT_FINI_ARRAY */	\
  _ (RUN_PATH, 29)		/* Library search path */		\
  _ (FLAGS, 30)			/* Flags for object being loaded */	\
  _ (ENCODING, 31)		/* Start of encoded range */		\
  _ (PREINIT_ARRAY, 32)		/* Array with addresses of fns */	\
  _ (PREINIT_ARRAY_SIZE, 33)	/* Size of PREINIT_ARRAY in bytes. */	\
  _ (GNU_PRELINKED, 0x6ffffdf5)	/* Prelinking timestamp */		\
  _ (GNU_CONFLICTSZ, 0x6ffffdf6)	/* Size of conflict section */	\
  _ (GNU_LIBLISTSZ, 0x6ffffdf7)	/* Size of library list */		\
  _ (CHECKSUM, 0x6ffffdf8)						\
  _ (PLTPADSZ, 0x6ffffdf9)						\
  _ (MOVEENT, 0x6ffffdfa)						\
  _ (MOVESZ, 0x6ffffdfb)						\
  _ (FEATURE_1,	0x6ffffdfc)	/* Feature selection (DTF_*).  */	\
  _ (POSFLAG_1,	0x6ffffdfd)	/* Flags for following entries.  */	\
  _ (SYMINSZ, 0x6ffffdfe)	/* Size of syminfo table (in bytes) */	\
  _ (SYMINENT, 0x6ffffdff)	/* Entry size of syminfo */		\
  _ (GNU_HASH, 0x6ffffef5)						\
  _ (GNU_CONFLICT, 0x6ffffef8)	/* Start of conflict section */		\
  _ (GNU_LIBLIST, 0x6ffffef9)	/* Library list */			\
  _ (CONFIG, 0x6ffffefa)	/* Configuration information.  */	\
  _ (DEPAUDIT, 0x6ffffefb)	/* Dependency auditing.  */		\
  _ (AUDIT, 0x6ffffefc)	/* Object auditing.  */				\
  _ (PLTPAD, 0x6ffffefd)	/* PLT padding.  */			\
  _ (MOVETAB, 0x6ffffefe)	/* Move table.  */			\
  _ (SYMINFO, 0x6ffffeff)	/* Syminfo table.  */			\
  _ (VERSYM, 0x6ffffff0)						\
  _ (RELACOUNT, 0x6ffffff9)						\
  _ (RELCOUNT, 0x6ffffffa)						\
  _ (FLAGS_1, 0x6ffffffb)	/* State flags, see DF_1_* below.  */	\
  _ (VERSION_DEF, 0x6ffffffc)	/* Address of version definition table */ \
  _ (VERSION_DEF_COUNT, 0x6ffffffd)	/* Number of version definitions */ \
  _ (VERSION_NEED, 0x6ffffffe)	/* Address of table with needed versions */ \
  _ (VERSION_NEED_COUNT, 0x6fffffff)	/* Number of needed versions */	\
  _ (AUXILIARY, 0x7ffffffd)      /* Shared object to load before self */ \
  _ (FILTER, 0x7fffffff)	/* Shared object to get values from */

typedef enum
{
#define _(f,n) ELF_DYNAMIC_ENTRY_##f = (n),
  foreach_elf_dynamic_entry_type
#undef _
} elf_dynamic_entry_type_t;

/* Values of `d_un.d_val' in the DT_FLAGS entry.  */
#define ELF_DYNAMIC_FLAGS_ORIGIN	(1 << 0)	/* Object may use DF_ORIGIN */
#define ELF_DYNAMIC_FLAGS_SYMBOLIC	(1 << 1)	/* Symbol resolutions starts here */
#define ELF_DYNAMIC_FLAGS_TEXT_RELOCATIONS (1 << 2)	/* Object contains text relocations */
#define ELF_DYNAMIC_FLAGS_BIND_NOW	(1 << 3)	/* No lazy binding for this object */
#define ELF_DYNAMIC_FLAGS_STATIC_TLS	(1 << 4)	/* Module uses the static TLS model */

/* State flags selectable in the `d_un.d_val' element of the DT_FLAGS_1
   entry in the dynamic section.  */
#define DF_1_NOW	0x00000001	/* Set RTLD_NOW for this object.  */
#define DF_1_GLOBAL	0x00000002	/* Set RTLD_GLOBAL for this object.  */
#define DF_1_GROUP	0x00000004	/* Set RTLD_GROUP for this object.  */
#define DF_1_NODELETE	0x00000008	/* Set RTLD_NODELETE for this object. */
#define DF_1_LOADFLTR	0x00000010	/* Trigger filtee loading at runtime. */
#define DF_1_INITFIRST	0x00000020	/* Set RTLD_INITFIRST for this object */
#define DF_1_NOOPEN	0x00000040	/* Set RTLD_NOOPEN for this object.  */
#define DF_1_ORIGIN	0x00000080	/* $ORIGIN must be handled.  */
#define DF_1_DIRECT	0x00000100	/* Direct binding enabled.  */
#define DF_1_TRANS	0x00000200
#define DF_1_INTERPOSE	0x00000400	/* Object is used to interpose.  */
#define DF_1_NODEFLIB	0x00000800	/* Ignore default lib search path.  */
#define DF_1_NODUMP	0x00001000	/* Object can't be dldump'ed.  */
#define DF_1_CONFALT	0x00002000	/* Configuration alternative created. */
#define DF_1_ENDFILTEE	0x00004000	/* Filtee terminates filters search. */
#define	DF_1_DISPRELDNE	0x00008000	/* Disp reloc applied at build time. */
#define	DF_1_DISPRELPND	0x00010000	/* Disp reloc applied at run-time.  */

/* Flags for the feature selection in DT_FEATURE_1.  */
#define DTF_1_PARINIT	0x00000001
#define DTF_1_CONFEXP	0x00000002

/* Flags in the DT_POSFLAG_1 entry effecting only the next DT_* entry.  */
#define DF_P1_LAZYLOAD	0x00000001	/* Lazyload following object.  */
#define DF_P1_GROUPPERM	0x00000002	/* Symbols from next object are not
					   generally available.  */

/* Version definition sections.  */
typedef struct
{
  u16 version;
  u16 flags;
  u16 index;
  u16 aux_count;
  u32 name_hash;
  u32 aux_byte_offset;
  u32 byte_offset_next_version_definition;
} elf_dynamic_version_definition_t;

typedef struct
{
  u32 name;
  u32 next_offset;		/* byte offset of ver def aux next entry */
} elf_dynamic_version_definition_aux_t;

/* Version definition flags. */
#define ELF_DYNAMIC_VERSION_FILE (1 << 0)	/* Version definition of file itself */
#define ELF_DYNAMIC_VERSION_WEAK (1 << 1)	/* Weak version identifier */

/* Version symbol index. */
#define	ELF_DYNAMIC_VERSYM_LOCAL 0	/* Symbol is local.  */
#define	ELF_DYNAMIC_VERSYM_GLOBAL 1	/* Symbol is global.  */
#define	ELF_DYNAMIC_VERSYM_RESERVED_LO	0xff00	/* Beginning of reserved entries.  */
#define	ELF_DYNAMIC_VERSYM_ELIMINATE	0xff01	/* Symbol is to be eliminated.  */

/* Version dependency section.  */
#define foreach_elf_dynamic_version_need_field	\
  _ (u16, version)				\
  _ (u16, aux_count)				\
  _ (u32, file_name_offset)			\
  _ (u32, first_aux_offset)			\
  _ (u32, next_offset)

#define foreach_elf_dynamic_version_need_aux_field	\
  _ (u32, hash)						\
  _ (u16, flags)					\
  _ (u16, versym_index)					\
  _ (u32, name)						\
  _ (u32, next_offset)

typedef struct
{
#define _(t,f) t f;
  foreach_elf_dynamic_version_need_field
#undef _
} elf_dynamic_version_need_t;

typedef struct
{
#define _(t,f) t f;
  foreach_elf_dynamic_version_need_aux_field
#undef _
} elf_dynamic_version_need_aux_t;

typedef union
{
  elf_dynamic_version_need_t need;
  elf_dynamic_version_need_aux_t aux;
} elf_dynamic_version_need_union_t;

/* Note section contents.  Each entry in the note section begins with
   a header of a fixed form.  */

typedef struct
{
  u32 name_size;
  u32 descriptor_size;
  u32 type;
} elf_note_t;

/* Known names of notes.  */

/* Solaris entries in the note section have this name.  */
#define ELF_NOTE_SOLARIS	"SUNW Solaris"

/* Note entries for GNU systems have this name.  */
#define ELF_NOTE_GNU		"GNU"


/* Defined types of notes for Solaris.  */

/* Value of descriptor (one word) is desired pagesize for the binary.  */
#define ELF_NOTE_PAGESIZE_HINT	1


/* Defined note types for GNU systems.  */

/* ABI information.  The descriptor consists of words:
   word 0: OS descriptor
   word 1: major version of the ABI
   word 2: minor version of the ABI
   word 3: subminor version of the ABI
*/
#ifndef ELF_NOTE_ABI
#define ELF_NOTE_ABI		1
#endif

/* Known OSes.  These value can appear in word 0 of an ELF_NOTE_ABI
   note section entry.  */
#define ELF_NOTE_OS_LINUX	0
#define ELF_NOTE_OS_GNU		1
#define ELF_NOTE_OS_SOLARIS2	2
#define ELF_NOTE_OS_FREEBSD	3

/* AMD x86-64 relocations.  */
#define foreach_elf_x86_64_relocation_type				\
  _ (NONE, 0)			/* No reloc */				\
  _ (DIRECT_64, 1)		/* Direct 64 bit  */			\
  _ (PC_REL_I32, 2)	        /* PC relative 32 bit signed */		\
  _ (GOT_REL_32, 3)		/* 32 bit GOT entry */			\
  _ (PLT_REL_32, 4)		/* 32 bit PLT address */		\
  _ (COPY, 5)			/* Copy symbol at runtime */		\
  _ (CREATE_GOT, 6)		/* Create GOT entry */			\
  _ (CREATE_PLT, 7)		/* Create PLT entry */			\
  _ (RELATIVE, 8)		/* Adjust by program base */		\
  _ (PC_REL_I32_GOT, 9)	/* 32 bit PC relative offset to GOT */		\
  _ (DIRECT_U32, 10)		/* Direct 32 bit zero extended */	\
  _ (DIRECT_I32, 11)		/* Direct 32 bit sign extended */	\
  _ (DIRECT_U16, 12)		/* Direct 16 bit zero extended */	\
  _ (PC_REL_I16, 13)	/* 16 bit sign extended pc relative */		\
  _ (DIRECT_I8, 14)		/* Direct 8 bit sign extended  */	\
  _ (PC_REL_I8, 15)	/* 8 bit sign extended pc relative */		\
  _ (DTPMOD64, 16)		/* ID of module containing symbol */	\
  _ (DTPOFF64, 17)		/* Offset in module's TLS block */	\
  _ (TPOFF64, 18)		/* Offset in initial TLS block */	\
  _ (TLSGD, 19)	/* 32 bit signed PC relative offset to two GOT entries for GD symbol */	\
  _ (TLSLD, 20) /* 32 bit signed PC relative offset to two GOT entries for LD symbol */	\
  _ (DTPOFF32, 21)		/* Offset in TLS block */		\
  _ (GOTTPOFF, 22) /* 32 bit signed PC relative offset to GOT entry for IE symbol */ \
  _ (TPOFF32, 23)		/* Offset in initial TLS, block) */

typedef struct
{
  elf64_symbol_t *symbols;

  u32 section_index;

  u8 *string_table;

  uword *symbol_by_name;
} elf_symbol_table_t;

always_inline void
elf_symbol_table_free (elf_symbol_table_t * s)
{
  vec_free (s->symbols);
  hash_free (s->symbol_by_name);
}

always_inline u8 *
elf_symbol_name (elf_symbol_table_t * t, elf64_symbol_t * sym)
{
  return vec_elt_at_index (t->string_table, sym->name);
}

typedef struct
{
  elf_relocation_with_addend_t *relocations;

  u32 section_index;
} elf_relocation_table_t;

always_inline void
elf_relocation_table_free (elf_relocation_table_t * r)
{
  vec_free (r->relocations);
}

typedef struct
{
  elf64_section_header_t header;

  u32 index;

  /* Index of segments containing this section. */
  uword *segment_index_bitmap;

  /* Aligned size (included padding not included in
     header.file_size). */
  u64 align_size;

  i64 exec_address_change;

  u8 *contents;
} elf_section_t;

typedef struct
{
  elf64_segment_header_t header;

  /* Sections contained in this segment. */
  uword *section_index_bitmap;

  u32 index;

  u8 *contents;
} elf_segment_t;

typedef struct
{
  u8 need_byte_swap;

  u8 parsed_symbols;

  char *file_name;

  elf_first_header_t first_header;

  elf64_file_header_t file_header;

  elf_segment_t *segments;

  elf_section_t *sections;

  uword *section_by_name;
  uword *section_by_start_address;

  elf_symbol_table_t *symbol_tables;
  elf_relocation_table_t *relocation_tables;

  char *interpreter;

  elf64_dynamic_entry_t *dynamic_entries;
  u8 *dynamic_string_table;
  u32 dynamic_string_table_section_index;
  u32 dynamic_symbol_table_section_index;
  u32 dynamic_symbol_table_index;
  u32 dynamic_section_index;
  u16 *versym;
  u32 versym_section_index;
  elf_dynamic_version_need_union_t *verneed;
  u32 verneed_section_index;
} elf_main_t;

always_inline void
elf_main_init (elf_main_t * em)
{
  clib_memset (em, 0, sizeof (em[0]));
}

always_inline void
elf_main_free (elf_main_t * em)
{
  uword i;

  for (i = 0; i < vec_len (em->segments); i++)
    vec_free (em->segments[i].contents);
  vec_free (em->segments);

  for (i = 0; i < vec_len (em->sections); i++)
    vec_free (em->sections[i].contents);
  vec_free (em->sections);

  hash_free (em->section_by_name);
  for (i = 0; i < vec_len (em->symbol_tables); i++)
    elf_symbol_table_free (em->symbol_tables + i);
  for (i = 0; i < vec_len (em->relocation_tables); i++)
    elf_relocation_table_free (em->relocation_tables + i);

  vec_free (em->dynamic_entries);
  vec_free (em->interpreter);
}

always_inline void
elf_get_segment_contents (elf_main_t * em, void *data, uword segment_index)
{
  elf_segment_t *g = vec_elt_at_index (em->segments, segment_index);
  if (!g->contents)
    vec_add (g->contents, data + g->header.file_offset,
	     g->header.memory_size);
}

always_inline void *
elf_get_section_contents (elf_main_t * em,
			  uword section_index, uword elt_size)
{
  elf_section_t *s;
  void *result;

  s = vec_elt_at_index (em->sections, section_index);

  result = 0;
  if (vec_len (s->contents) > 0)
    {
      /* Make vector copy of contents with given element size. */
      result = _vec_resize (result,
			    vec_len (s->contents) / elt_size,
			    vec_len (s->contents),
			    /* header_bytes */ 0,
			    /* align */ 0);
      clib_memcpy (result, s->contents, vec_len (s->contents));
    }

  return result;
}

always_inline void
elf_set_section_contents (elf_main_t * em,
			  uword section_index,
			  void *new_contents, uword n_content_bytes)
{
  elf_section_t *s;

  s = vec_elt_at_index (em->sections, section_index);
  vec_free (s->contents);
  vec_add (s->contents, new_contents, n_content_bytes);
}

always_inline u8 *
elf_section_name (elf_main_t * em, elf_section_t * s)
{
  elf_section_t *es = vec_elt_at_index (em->sections,
					em->
					file_header.section_header_string_table_index);
  return vec_elt_at_index (es->contents, s->header.name);
}

always_inline u8
elf_swap_u8 (elf_main_t * em, u8 x)
{
  return x;
}

always_inline u16
elf_swap_u16 (elf_main_t * em, u16 x)
{
  return em->need_byte_swap ? clib_byte_swap_u16 (x) : x;
}

always_inline u32
elf_swap_u32 (elf_main_t * em, u32 x)
{
  return em->need_byte_swap ? clib_byte_swap_u32 (x) : x;
}

always_inline u64
elf_swap_u64 (elf_main_t * em, u64 x)
{
  return em->need_byte_swap ? clib_byte_swap_u64 (x) : x;
}

#define FORMAT_ELF_MAIN_SYMBOLS (1 << 0)
#define FORMAT_ELF_MAIN_RELOCATIONS (1 << 1)
#define FORMAT_ELF_MAIN_DYNAMIC (1 << 2)

format_function_t format_elf_main;
format_function_t format_elf_symbol;

clib_error_t *elf_read_file (elf_main_t * em, char *file_name);
clib_error_t *elf_write_file (elf_main_t * em, char *file_name);
clib_error_t *elf_delete_named_section (elf_main_t * em, char *section_name);
clib_error_t *elf_parse (elf_main_t * em, void *data, uword data_bytes);
void elf_parse_symbols (elf_main_t * em);

clib_error_t *elf_get_section_by_name (elf_main_t * em, char *section_name,
				       elf_section_t ** result);
clib_error_t *elf_get_section_by_start_address (elf_main_t * em,
						uword start_address,
						elf_section_t ** result);

void
elf_create_section_with_contents (elf_main_t * em,
				  char *section_name,
				  elf64_section_header_t * header,
				  void *contents, uword n_content_bytes);
uword elf_delete_segment_with_type (elf_main_t * em,
				    elf_segment_type_t segment_type);
void elf_set_dynamic_entries (elf_main_t * em);

#endif /* included_clib_elf_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */