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[ipv6] Expose NDP-provided settings (including the DNS server)
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Signed-off-by: Michael Brown <mcb30@ipxe.org>
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@mcb30
mcb30 committed Dec 5, 2013
1 parent 4a6c453 commit 99c6796
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Showing 2 changed files with 234 additions and 9 deletions.
37 changes: 37 additions & 0 deletions src/include/ipxe/ndp.h
View file
Expand Up @@ -67,6 +67,36 @@ struct ndp_prefix_information_option {
/** NDP autonomous address configuration flag */
#define NDP_PREFIX_AUTONOMOUS 0x40

/** NDP recursive DNS server option */
#define NDP_OPT_RDNSS 25

/** NDP recursive DNS server */
struct ndp_rdnss_option {
/** NDP option header */
struct ndp_option_header header;
/** Reserved */
uint16_t reserved;
/** Lifetime */
uint32_t lifetime;
/** Addresses */
struct in6_addr addresses[0];
} __attribute__ (( packed ));

/** NDP DNS search list option */
#define NDP_OPT_DNSSL 31

/** NDP DNS search list */
struct ndp_dnssl_option {
/** NDP option header */
struct ndp_option_header header;
/** Reserved */
uint16_t reserved;
/** Lifetime */
uint32_t lifetime;
/** Domain names */
uint8_t names[0];
} __attribute__ (( packed ));

/** An NDP option */
union ndp_option {
/** Option header */
Expand All @@ -75,6 +105,10 @@ union ndp_option {
struct ndp_ll_addr_option ll_addr;
/** Prefix information option */
struct ndp_prefix_information_option prefix;
/** Recursive DNS server option */
struct ndp_rdnss_option rdnss;
/** DNS search list option */
struct ndp_dnssl_option dnssl;
} __attribute__ (( packed ));

/** An NDP neighbour solicitation or advertisement header */
Expand Down Expand Up @@ -166,4 +200,7 @@ static inline int ndp_tx ( struct io_buffer *iobuf, struct net_device *netdev,
&ndp_discovery, net_source, ll_source );
}

/** NDP settings block name */
#define NDP_SETTINGS_NAME "ndp"

#endif /* _IPXE_NDP_H */
206 changes: 197 additions & 9 deletions src/net/ndp.c
View file
Expand Up @@ -38,8 +38,10 @@ FILE_LICENCE ( GPL2_OR_LATER );
*
*/

static int ipv6conf_rx_router_advertisement ( struct net_device *netdev,
unsigned int flags );
static int
ipv6conf_rx_router_advertisement ( struct net_device *netdev,
struct ndp_router_advertisement_header *radv,
size_t len );

/**
* Transmit NDP packet with link-layer address option
Expand Down Expand Up @@ -585,8 +587,8 @@ ndp_rx_router_advertisement ( struct io_buffer *iobuf,
goto err_options;

/* Pass to IPv6 autoconfiguration */
if ( ( rc = ipv6conf_rx_router_advertisement ( netdev,
radv->flags ) ) != 0 )
if ( ( rc = ipv6conf_rx_router_advertisement ( netdev, radv,
len ) ) != 0 )
goto err_ipv6conf;

err_ipv6conf:
Expand All @@ -611,6 +613,179 @@ struct icmpv6_handler ndp_handlers[] __icmpv6_handler = {
},
};

/****************************************************************************
*
* NDP settings
*
*/

/** An NDP settings block */
struct ndp_settings {
/** Reference counter */
struct refcnt refcnt;
/** Settings interface */
struct settings settings;
/** Length of NDP options */
size_t len;
/** NDP options */
union ndp_option option[0];
};

/** NDP settings scope */
static const struct settings_scope ndp_settings_scope;

/**
* Construct NDP tag
*
* @v type NDP option type
* @v offset Starting offset of data
* @ret tag NDP tag
*/
#define NDP_TAG( type, offset ) ( ( (offset) << 8 ) | (type) )

/**
* Extract NDP tag type
*
* @v tag NDP tag
* @ret type NDP option type
*/
#define NDP_TAG_TYPE( tag ) ( (tag) & 0xff )

/**
* Extract NDP tag offset
*
* @v tag NDP tag
* @ret offset Starting offset of data
*/
#define NDP_TAG_OFFSET( tag ) ( (tag) >> 8 )

/**
* Check applicability of NDP setting
*
* @v settings Settings block
* @v setting Setting to fetch
* @ret applies Setting applies within this settings block
*/
static int ndp_applies ( struct settings *settings __unused,
const struct setting *setting ) {

return ( setting->scope == &ndp_settings_scope );
}

/**
* Fetch value of NDP setting
*
* @v settings Settings block
* @v setting Setting to fetch
* @v data Buffer to fill with setting data
* @v len Length of buffer
* @ret len Length of setting data, or negative error
*/
static int ndp_fetch ( struct settings *settings,
struct setting *setting,
void *data, size_t len ) {
struct ndp_settings *ndpset =
container_of ( settings, struct ndp_settings, settings );
struct net_device *netdev =
container_of ( settings->parent, struct net_device,
settings.settings );
union ndp_option *option;
unsigned int type = NDP_TAG_TYPE ( setting->tag );
unsigned int offset = NDP_TAG_OFFSET ( setting->tag );
size_t remaining;
size_t option_len;
size_t payload_len;

/* Scan through NDP options for requested type. We can assume
* that the options are well-formed, otherwise they would have
* been rejected prior to being stored.
*/
option = ndpset->option;
remaining = ndpset->len;
while ( remaining ) {

/* Calculate option length */
option_len = ( option->header.blocks * NDP_OPTION_BLKSZ );

/* If this is the requested option, return it */
if ( option->header.type == type ) {

/* Sanity check */
if ( offset > option_len ) {
DBGC ( netdev, "NDP %s option %d too short\n",
netdev->name, type );
return -EINVAL;
}
payload_len = ( option_len - offset );

/* Copy data to output buffer */
if ( len > payload_len )
len = payload_len;
memcpy ( data, ( ( ( void * ) option ) + offset ), len);
return payload_len;
}

/* Move to next option */
option = ( ( ( void * ) option ) + option_len );
remaining -= option_len;
}

return -ENOENT;
}

/** NDP settings operations */
static struct settings_operations ndp_settings_operations = {
.applies = ndp_applies,
.fetch = ndp_fetch,
};

/**
* Register NDP settings
*
* @v netdev Network device
* @v option NDP options
* @v len Length of options
* @ret rc Return status code
*/
static int ndp_register_settings ( struct net_device *netdev,
union ndp_option *option, size_t len ) {
struct settings *parent = netdev_settings ( netdev );
struct ndp_settings *ndpset;
int rc;

/* Allocate and initialise structure */
ndpset = zalloc ( sizeof ( *ndpset ) + len );
if ( ! ndpset ) {
rc = -ENOMEM;
goto err_alloc;
}
ref_init ( &ndpset->refcnt, NULL );
settings_init ( &ndpset->settings, &ndp_settings_operations,
&ndpset->refcnt, &ndp_settings_scope );
ndpset->len = len;
memcpy ( ndpset->option, option, len );

/* Register settings */
if ( ( rc = register_settings ( &ndpset->settings, parent,
NDP_SETTINGS_NAME ) ) != 0 )
goto err_register;

err_register:
ref_put ( &ndpset->refcnt );
err_alloc:
return rc;
}

/** DNS server setting */
const struct setting ndp_dns6_setting __setting ( SETTING_IP_EXTRA, dns6 ) = {
.name = "dns6",
.description = "DNS server",
.tag = NDP_TAG ( NDP_OPT_RDNSS,
offsetof ( struct ndp_rdnss_option, addresses ) ),
.type = &setting_type_ipv6,
.scope = &ndp_settings_scope,
};

/****************************************************************************
*
* IPv6 autoconfiguration
Expand Down Expand Up @@ -713,12 +888,19 @@ static void ipv6conf_expired ( struct retry_timer *timer, int fail ) {
* Handle router advertisement during IPv6 autoconfiguration
*
* @v netdev Network device
* @v flags Router flags
* @v radv Router advertisement
* @v len Length of router advertisement
* @ret rc Return status code
*
* This function assumes that the router advertisement is well-formed,
* since it must have already passed through option processing.
*/
static int ipv6conf_rx_router_advertisement ( struct net_device *netdev,
unsigned int flags ) {
static int
ipv6conf_rx_router_advertisement ( struct net_device *netdev,
struct ndp_router_advertisement_header *radv,
size_t len ) {
struct ipv6conf *ipv6conf;
size_t option_len;
int stateful;
int rc;

Expand All @@ -739,9 +921,15 @@ static int ipv6conf_rx_router_advertisement ( struct net_device *netdev,
/* Stop router solicitation timer */
stop_timer ( &ipv6conf->timer );

/* Register NDP settings */
option_len = ( len - offsetof ( typeof ( *radv ), option ) );
if ( ( rc = ndp_register_settings ( netdev, radv->option,
option_len ) ) != 0 )
return rc;

/* Start DHCPv6 if required */
if ( flags & ( NDP_ROUTER_MANAGED | NDP_ROUTER_OTHER ) ) {
stateful = ( flags & NDP_ROUTER_MANAGED );
if ( radv->flags & ( NDP_ROUTER_MANAGED | NDP_ROUTER_OTHER ) ) {
stateful = ( radv->flags & NDP_ROUTER_MANAGED );
if ( ( rc = start_dhcpv6 ( &ipv6conf->dhcp, netdev,
stateful ) ) != 0 ) {
DBGC ( netdev, "NDP %s could not start state%s DHCPv6: "
Expand Down

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