diff options
| -rw-r--r-- | src/core/cachedhcp.c | 51 |
1 files changed, 42 insertions, 9 deletions
diff --git a/src/core/cachedhcp.c b/src/core/cachedhcp.c index 2fa9b0c73..c4ca46e3a 100644 --- a/src/core/cachedhcp.c +++ b/src/core/cachedhcp.c @@ -90,29 +90,62 @@ static void cachedhcp_free ( struct cached_dhcp_packet *cache ) { */ static int cachedhcp_apply ( struct cached_dhcp_packet *cache, struct net_device *netdev ) { - struct settings *settings; + struct settings *settings = NULL; + struct ll_protocol *ll_protocol; + const uint8_t *chaddr; + uint8_t *hw_addr; + uint8_t *ll_addr; + size_t ll_addr_len; int rc; /* Do nothing if cache is empty */ if ( ! cache->dhcppkt ) return 0; + chaddr = cache->dhcppkt->dhcphdr->chaddr; - /* Do nothing unless cached packet's MAC address matches this - * network device, if specified. - */ + /* Handle association with network device, if specified */ if ( netdev ) { - if ( memcmp ( netdev->ll_addr, cache->dhcppkt->dhcphdr->chaddr, - netdev->ll_protocol->ll_addr_len ) != 0 ) { + hw_addr = netdev->hw_addr; + ll_addr = netdev->ll_addr; + ll_protocol = netdev->ll_protocol; + ll_addr_len = ll_protocol->ll_addr_len; + + /* If cached packet's MAC address matches the network + * device's permanent MAC address, then assume that + * the permanent MAC address ought to be the network + * device's current link-layer address. + * + * This situation can arise when the PXE ROM does not + * understand the system-specific mechanism for + * overriding the MAC address, and so uses the + * permanent MAC address instead. We choose to match + * this behaviour in order to minimise surprise. + */ + if ( memcmp ( hw_addr, chaddr, ll_addr_len ) == 0 ) { + if ( memcmp ( hw_addr, ll_addr, ll_addr_len ) != 0 ) { + DBGC ( colour, "CACHEDHCP %s resetting %s MAC " + "%s ", cache->name, netdev->name, + ll_protocol->ntoa ( ll_addr ) ); + DBGC ( colour, "-> %s\n", + ll_protocol->ntoa ( hw_addr ) ); + } + memcpy ( ll_addr, hw_addr, ll_addr_len ); + } + + /* Do nothing unless cached packet's MAC address + * matches this network device. + */ + if ( memcmp ( ll_addr, chaddr, ll_addr_len ) != 0 ) { DBGC ( colour, "CACHEDHCP %s does not match %s\n", cache->name, netdev->name ); return 0; } DBGC ( colour, "CACHEDHCP %s is for %s\n", cache->name, netdev->name ); - } - /* Select appropriate parent settings block */ - settings = ( netdev ? netdev_settings ( netdev ) : NULL ); + /* Use network device's settings block */ + settings = netdev_settings ( netdev ); + } /* Register settings */ if ( ( rc = register_settings ( &cache->dhcppkt->settings, settings, |