iPXE
Functions | Variables
cachedhcp.h File Reference

Cached DHCP packet. More...

#include <stddef.h>
#include <ipxe/uaccess.h>

Go to the source code of this file.

Functions

 FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
 
int cachedhcp_record (struct cached_dhcp_packet *cache, unsigned int vlan, userptr_t data, size_t max_len)
 Record cached DHCP packet. More...
 

Variables

struct cached_dhcp_packet cached_dhcpack
 Cached DHCPACK. More...
 
struct cached_dhcp_packet cached_proxydhcp
 Cached ProxyDHCPOFFER. More...
 
struct cached_dhcp_packet cached_pxebs
 Cached PXEBSACK. More...
 

Detailed Description

Cached DHCP packet.

Definition in file cachedhcp.h.

Function Documentation

◆ FILE_LICENCE()

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL  )

◆ cachedhcp_record()

int cachedhcp_record ( struct cached_dhcp_packet cache,
unsigned int  vlan,
userptr_t  data,
size_t  max_len 
)

Record cached DHCP packet.

Parameters
cacheCached DHCP packet
vlanVLAN tag, if any
dataDHCPACK packet buffer
max_lenMaximum possible length
Return values
rcReturn status code

Definition at line 187 of file cachedhcp.c.

188  {
189  struct dhcp_packet *dhcppkt;
190  struct dhcp_packet *tmp;
191  struct dhcphdr *dhcphdr;
192  unsigned int i;
193  size_t len;
194 
195  /* Free any existing cached packet */
196  cachedhcp_free ( cache );
197 
198  /* Allocate and populate DHCP packet */
199  dhcppkt = zalloc ( sizeof ( *dhcppkt ) + max_len );
200  if ( ! dhcppkt ) {
201  DBGC ( colour, "CACHEDHCP %s could not allocate copy\n",
202  cache->name );
203  return -ENOMEM;
204  }
205  dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
207  dhcppkt_init ( dhcppkt, dhcphdr, max_len );
208 
209  /* Shrink packet to required length. If reallocation fails,
210  * just continue to use the original packet and waste the
211  * unused space.
212  */
213  len = dhcppkt_len ( dhcppkt );
214  assert ( len <= max_len );
215  tmp = realloc ( dhcppkt, ( sizeof ( *dhcppkt ) + len ) );
216  if ( tmp )
217  dhcppkt = tmp;
218 
219  /* Reinitialise packet at new address */
220  dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
221  dhcppkt_init ( dhcppkt, dhcphdr, len );
222 
223  /* Discard duplicate packets, since some PXE stacks (including
224  * iPXE itself) will report the DHCPACK packet as the PXEBSACK
225  * if no separate PXEBSACK exists.
226  */
227  for ( i = 0 ; i < ( sizeof ( cached_packets ) /
228  sizeof ( cached_packets[0] ) ) ; i++ ) {
229  tmp = cached_packets[i]->dhcppkt;
230  if ( tmp && ( dhcppkt_len ( tmp ) == len ) &&
231  ( memcmp ( tmp->dhcphdr, dhcppkt->dhcphdr, len ) == 0 ) ) {
232  DBGC ( colour, "CACHEDHCP %s duplicates %s\n",
233  cache->name, cached_packets[i]->name );
234  dhcppkt_put ( dhcppkt );
235  return -EEXIST;
236  }
237  }
238 
239  /* Store as cached packet */
240  DBGC ( colour, "CACHEDHCP %s at %#08lx+%#zx/%#zx\n", cache->name,
241  user_to_phys ( data, 0 ), len, max_len );
242  cache->dhcppkt = dhcppkt;
243  cache->vlan = vlan;
244 
245  return 0;
246 }
#define colour
Colour for debug messages.
Definition: cachedhcp.c:74
A DHCP packet.
Definition: dhcppkt.h:20
unsigned int vlan
VLAN tag (if applicable)
Definition: cachedhcp.c:48
#define EEXIST
File exists.
Definition: errno.h:388
uint16_t max_len
Maximum length (in bytes)
Definition: ntlm.h:18
static __always_inline void copy_from_user(void *dest, userptr_t src, off_t src_off, size_t len)
Copy data from user buffer.
Definition: uaccess.h:337
unsigned long user_to_phys(userptr_t userptr, off_t offset)
Convert user pointer to physical address.
#define DBGC(...)
Definition: compiler.h:505
static struct cached_dhcp_packet * cached_packets[]
List of cached DHCP packets.
Definition: cachedhcp.c:67
struct dhcp_packet * dhcppkt
DHCP packet (if any)
Definition: cachedhcp.c:46
static void cachedhcp_free(struct cached_dhcp_packet *cache)
Free cached DHCP packet.
Definition: cachedhcp.c:81
unsigned long tmp
Definition: linux_pci.h:53
#define ENOMEM
Not enough space.
Definition: errno.h:534
assert((readw(&hdr->flags) &(GTF_reading|GTF_writing))==0)
void * zalloc(size_t size)
Allocate cleared memory.
Definition: malloc.c:624
A DHCP header.
Definition: dhcp.h:613
void dhcppkt_init(struct dhcp_packet *dhcppkt, struct dhcphdr *data, size_t len)
Initialise DHCP packet.
Definition: dhcppkt.c:300
struct dhcphdr * dhcphdr
The DHCP packet contents.
Definition: dhcppkt.h:24
uint32_t len
Length.
Definition: ena.h:14
static void dhcppkt_put(struct dhcp_packet *dhcppkt)
Decrement reference count on DHCP packet.
Definition: dhcppkt.h:49
static size_t dhcppkt_len(struct dhcp_packet *dhcppkt)
Get used length of DHCP packet.
Definition: dhcppkt.h:59
const char * name
Settings block name.
Definition: cachedhcp.c:44
uint8_t data[48]
Additional event data.
Definition: ena.h:22
void * realloc(void *old_ptr, size_t new_size)
Reallocate memory.
Definition: malloc.c:521
int memcmp(const void *first, const void *second, size_t len)
Compare memory regions.
Definition: string.c:114

References assert(), cached_packets, cachedhcp_free(), colour, copy_from_user(), data, DBGC, dhcp_packet::dhcphdr, cached_dhcp_packet::dhcppkt, dhcppkt_init(), dhcppkt_len(), dhcppkt_put(), EEXIST, ENOMEM, len, max_len, memcmp(), cached_dhcp_packet::name, realloc(), tmp, user_to_phys(), cached_dhcp_packet::vlan, and zalloc().

Referenced by cachedhcp_init(), and efi_cachedhcp_record().

Variable Documentation

◆ cached_dhcpack

struct cached_dhcp_packet cached_dhcpack

Cached DHCPACK.

Definition at line 52 of file cachedhcp.c.

Referenced by cachedhcp_init(), cachedhcp_probe(), cachedhcp_shutdown(), cachedhcp_startup(), and efi_cachedhcp_record().

◆ cached_proxydhcp

struct cached_dhcp_packet cached_proxydhcp

Cached ProxyDHCPOFFER.

Definition at line 57 of file cachedhcp.c.

Referenced by cachedhcp_startup(), and efi_cachedhcp_record().

◆ cached_pxebs

struct cached_dhcp_packet cached_pxebs

Cached PXEBSACK.

Definition at line 62 of file cachedhcp.c.

Referenced by cachedhcp_startup(), and efi_cachedhcp_record().