cachedhcp.h File Reference

Cached DHCP packet. More...

#include <stddef.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
	FILE_SECBOOT (PERMITTED)
int	cachedhcp_record (struct cached_dhcp_packet *cache, unsigned int vlan, const void *data, size_t max_len)
	Record cached DHCP packet.
void	cachedhcp_recycle (struct net_device *netdev)
	Recycle cached DHCPACK.

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

Detailed Description

Cached DHCP packet.

Definition in file cachedhcp.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

FILE_SECBOOT()

FILE_SECBOOT

(

PERMITTED

)

References cached_dhcpack, cached_proxydhcp, cached_pxebs, data, and netdev.

cachedhcp_record()

int cachedhcp_record ( struct cached_dhcp_packet * cache, unsigned int vlan, const void * data, size_t max_len )

extern

Record cached DHCP packet.

Parameters

cache	Cached DHCP packet
vlan	VLAN tag, if any
data	DHCPACK packet buffer
max_len	Maximum possible length

Return values

rc	Return status code

Definition at line 206 of file cachedhcp.c.

                                                          {
        struct dhcp_packet *dhcppkt;
        struct dhcp_packet *tmp;
        struct dhcphdr *dhcphdr;
        unsigned int i;
        size_t len;
 
        /* Free any existing cached packet */
        cachedhcp_free ( cache );
 
        /* Allocate and populate DHCP packet */
        dhcppkt = zalloc ( sizeof ( *dhcppkt ) + max_len );
        if ( ! dhcppkt ) {
                DBGC ( colour, "CACHEDHCP %s could not allocate copy\n",
                       cache->name );
                return -ENOMEM;
        }
        dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
        memcpy ( dhcphdr, data, max_len );
        dhcppkt_init ( dhcppkt, dhcphdr, max_len );
 
        /* Shrink packet to required length.  If reallocation fails,
         * just continue to use the original packet and waste the
         * unused space.
         */
        len = dhcppkt_len ( dhcppkt );
        assert ( len <= max_len );
        tmp = realloc ( dhcppkt, ( sizeof ( *dhcppkt ) + len ) );
        if ( tmp )
                dhcppkt = tmp;
 
        /* Reinitialise packet at new address */
        dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
        dhcppkt_init ( dhcppkt, dhcphdr, len );
 
        /* Discard duplicate packets, since some PXE stacks (including
         * iPXE itself) will report the DHCPACK packet as the PXEBSACK
         * if no separate PXEBSACK exists.
         */
        for ( i = 0 ; i < ( sizeof ( cached_packets ) /
                            sizeof ( cached_packets[0] ) ) ; i++ ) {
                tmp = cached_packets[i]->dhcppkt;
                if ( tmp && ( dhcppkt_len ( tmp ) == len ) &&
                     ( memcmp ( tmp->dhcphdr, dhcppkt->dhcphdr, len ) == 0 ) ) {
                        DBGC ( colour, "CACHEDHCP %s duplicates %s\n",
                               cache->name, cached_packets[i]->name );
                        dhcppkt_put ( dhcppkt );
                        return -EEXIST;
                }
        }
 
        /* Store as cached packet */
        DBGC ( colour, "CACHEDHCP %s at %#08lx+%#zx/%#zx\n", cache->name,
               virt_to_phys ( data ), len, max_len );
        cache->dhcppkt = dhcppkt;
        cache->vlan = vlan;
 
        return 0;
}

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

Referenced by cachedhcp_init(), and efi_cachedhcp_record().

cachedhcp_recycle()

void cachedhcp_recycle ( struct net_device * netdev )

extern

Recycle cached DHCPACK.

Parameters

netdev	Network device
priv	Private data

Definition at line 358 of file cachedhcp.c.

                                                     {
        struct cached_dhcp_packet *cache = &cached_dhcpack;
        struct settings *settings;
 
        /* Return DHCPACK to cache, if applicable */
        settings = find_child_settings ( netdev_settings ( netdev ),
                                         cache->name );
        if ( cache->dhcppkt && ( settings == &cache->dhcppkt->settings ) ) {
                DBGC ( colour, "CACHEDHCP %s recycled from %s\n",
                       cache->name, netdev->name );
                assert ( cache->flags & CACHEDHCP_USED );
                unregister_settings ( settings );
                cache->flags &= ~CACHEDHCP_USED;
        }
}

References assert, cached_dhcpack, CACHEDHCP_USED, colour, DBGC, cached_dhcp_packet::dhcppkt, find_child_settings(), cached_dhcp_packet::flags, cached_dhcp_packet::name, netdev, netdev_settings(), dhcp_packet::settings, and unregister_settings().

Referenced by mnptemp_destroy().

Variable Documentation

cached_dhcpack

struct cached_dhcp_packet cached_dhcpack

extern

Cached DHCPACK.

Definition at line 63 of file cachedhcp.c.

                                           {
        .name = DHCP_SETTINGS_NAME,
        .flags = CACHEDHCP_RETAIN,
};

Referenced by cachedhcp_init(), cachedhcp_probe(), cachedhcp_recycle(), cachedhcp_shutdown(), cachedhcp_startup_late(), efi_cachedhcp_record(), and FILE_SECBOOT().

cached_proxydhcp

struct cached_dhcp_packet cached_proxydhcp

extern

Cached ProxyDHCPOFFER.

Definition at line 69 of file cachedhcp.c.

                                             {
        .name = PROXYDHCP_SETTINGS_NAME,
};

Referenced by cachedhcp_startup_early(), efi_cachedhcp_record(), and FILE_SECBOOT().

cached_pxebs

struct cached_dhcp_packet cached_pxebs

extern

Cached PXEBSACK.

Definition at line 74 of file cachedhcp.c.

                                         {
        .name = PXEBS_SETTINGS_NAME,
};

Referenced by cachedhcp_startup_early(), efi_cachedhcp_record(), and FILE_SECBOOT().