From 9a6964e419c0a533e1ca5d224221e440093a9e5f Mon Sep 17 00:00:00 2001 From: Sean Edmond Date: Mon, 24 Mar 2025 13:48:45 -0700 Subject: [PATCH] net: dhcp6: Send DHCPv6 using multicast MAC In IPv6, the broadcast MAC address is not used. Instead, it should use the multicast address (see RFC RFC2464). Add IPV6_ALL_NODE_ETH_ADDR macro for clarity. Signed-off-by: Sean Edmond Reviewed-by: Jerome Forissier --- include/net6.h | 10 ++++++++++ net/dhcpv6.c | 12 ++++++------ net/dhcpv6.h | 8 +++++++- 3 files changed, 23 insertions(+), 7 deletions(-) diff --git a/include/net6.h b/include/net6.h index 1ed989e584a..2ceeaba0639 100644 --- a/include/net6.h +++ b/include/net6.h @@ -90,6 +90,16 @@ struct udp_hdr { 0x00, 0x00, 0x00, 0x00, \ 0x00, 0x00, 0x00, 0x00, \ 0x00, 0x00, 0x00, 0x02 } } } +/* + * With IPv6, the broadcast MAC address is not used. Instead, it should use + * the multicast address (see RFC RFC2464 section 7) + */ +#define IPV6_ALL_NODE_ETH_ADDR(_ip6_addr) {0x33, \ + 0x33, \ + _ip6_addr.in6_u.u6_addr8[12], \ + _ip6_addr.in6_u.u6_addr8[13], \ + _ip6_addr.in6_u.u6_addr8[14], \ + _ip6_addr.in6_u.u6_addr8[15]} #define IPV6_LINK_LOCAL_PREFIX 0xfe80 #define IPV6_LINK_LOCAL_MASK 0xffb0 /* The first 10-bit of address mask. */ diff --git a/net/dhcpv6.c b/net/dhcpv6.c index 54619ee6983..984a64a4ff3 100644 --- a/net/dhcpv6.c +++ b/net/dhcpv6.c @@ -29,6 +29,10 @@ int updated_sol_max_rt_ms = SOL_MAX_RT_MS; /* state machine parameters/variables */ struct dhcp6_sm_params sm_params; +/* DHCPv6 all server IP6 address */ +const struct in6_addr dhcp_mcast_ip6 = DHCP6_MULTICAST_ADDR; +/* IPv6 multicast ethernet address */ +const u8 net_dhcp6_mcast_ethaddr[6] = IPV6_ALL_NODE_ETH_ADDR(dhcp_mcast_ip6); static void dhcp6_state_machine(bool timeout, uchar *rx_pkt, unsigned int len); @@ -171,7 +175,6 @@ static int dhcp6_add_option(int option_id, uchar *pkt) */ static void dhcp6_send_solicit_packet(void) { - struct in6_addr dhcp_bcast_ip6; int len = 0; uchar *pkt; uchar *dhcp_pkt_start_ptr; @@ -200,9 +203,8 @@ static void dhcp6_send_solicit_packet(void) len = pkt - dhcp_pkt_start_ptr; /* send UDP packet to DHCP6 multicast address */ - string_to_ip6(DHCP6_MULTICAST_ADDR, sizeof(DHCP6_MULTICAST_ADDR), &dhcp_bcast_ip6); net_set_udp_handler(dhcp6_handler); - net_send_udp_packet6((uchar *)net_bcast_ethaddr, &dhcp_bcast_ip6, + net_send_udp_packet6((uchar *)net_dhcp6_mcast_ethaddr, (struct in6_addr *)&dhcp_mcast_ip6, PORT_DHCP6_S, PORT_DHCP6_C, len); } @@ -218,7 +220,6 @@ static void dhcp6_send_solicit_packet(void) */ static void dhcp6_send_request_packet(void) { - struct in6_addr dhcp_bcast_ip6; int len = 0; uchar *pkt; uchar *dhcp_pkt_start_ptr; @@ -252,9 +253,8 @@ static void dhcp6_send_request_packet(void) len = pkt - dhcp_pkt_start_ptr; /* send UDP packet to DHCP6 multicast address */ - string_to_ip6(DHCP6_MULTICAST_ADDR, strlen(DHCP6_MULTICAST_ADDR), &dhcp_bcast_ip6); net_set_udp_handler(dhcp6_handler); - net_send_udp_packet6((uchar *)net_bcast_ethaddr, &dhcp_bcast_ip6, + net_send_udp_packet6((uchar *)net_dhcp6_mcast_ethaddr, (struct in6_addr *)&dhcp_mcast_ip6, PORT_DHCP6_S, PORT_DHCP6_C, len); } diff --git a/net/dhcpv6.h b/net/dhcpv6.h index 65c8e4c71d3..d41a3c30615 100644 --- a/net/dhcpv6.h +++ b/net/dhcpv6.h @@ -40,7 +40,13 @@ /* vendor-class-data to send in vendor clas option */ #define DHCP6_VCI_STRING "U-Boot" -#define DHCP6_MULTICAST_ADDR "ff02::1:2" /* DHCP multicast address */ +/* + * All-DHCPv6 server multicast address + */ +#define DHCP6_MULTICAST_ADDR { { { 0xFF, 0x02, 0x00, 0x00, \ + 0x00, 0x00, 0x00, 0x00, \ + 0x00, 0x00, 0x00, 0x00, \ + 0x00, 0x01, 0x00, 0x02 } } } /* DHCP6 States supported */ enum dhcp6_state { -- 2.39.5