// SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2013 Allied Telesis Labs NZ * Chris Packham, * * Copyright (C) 2022 YADRO * Viacheslav Mitrofanov */ /* Neighbour Discovery for IPv6 */ #include #include #include #include /* IPv6 destination address of packet waiting for ND */ struct in6_addr net_nd_sol_packet_ip6 = ZERO_IPV6_ADDR; /* IPv6 address we are expecting ND advert from */ static struct in6_addr net_nd_rep_packet_ip6 = ZERO_IPV6_ADDR; /* MAC destination address of packet waiting for ND */ uchar *net_nd_packet_mac; /* pointer to packet waiting to be transmitted after ND is resolved */ uchar *net_nd_tx_packet; static uchar net_nd_packet_buf[PKTSIZE_ALIGN + PKTALIGN]; /* size of packet waiting to be transmitted */ int net_nd_tx_packet_size; /* the timer for ND resolution */ ulong net_nd_timer_start; /* the number of requests we have sent so far */ int net_nd_try; #define IP6_NDISC_OPT_SPACE(len) (((len) + 2 + 7) & ~7) /** * ndisc_insert_option() - Insert an option into a neighbor discovery packet * * @ndisc: pointer to ND packet * @type: option type to insert * @data: option data to insert * @len: data length * Return: the number of bytes inserted (which may be >= len) */ static int ndisc_insert_option(struct nd_msg *ndisc, int type, u8 *data, int len) { int space = IP6_NDISC_OPT_SPACE(len); ndisc->opt[0] = type; ndisc->opt[1] = space >> 3; memcpy(&ndisc->opt[2], data, len); len += 2; /* fill the remainder with 0 */ if (space - len > 0) memset(&ndisc->opt[len], '\0', space - len); return space; } /** * ndisc_extract_enetaddr() - Extract the Ethernet address from a ND packet * * Note that the link layer address could be anything but the only networking * media that u-boot supports is Ethernet so we assume we're extracting a 6 * byte Ethernet MAC address. * * @ndisc: pointer to ND packet * @enetaddr: extracted MAC addr */ static void ndisc_extract_enetaddr(struct nd_msg *ndisc, uchar enetaddr[6]) { memcpy(enetaddr, &ndisc->opt[2], 6); } /** * ndisc_has_option() - Check if the ND packet has the specified option set * * @ip6: pointer to IPv6 header * @type: option type to check * Return: 1 if ND has that option, 0 therwise */ static int ndisc_has_option(struct ip6_hdr *ip6, __u8 type) { struct nd_msg *ndisc = (struct nd_msg *)(((uchar *)ip6) + IP6_HDR_SIZE); if (ip6->payload_len <= sizeof(struct icmp6hdr)) return 0; return ndisc->opt[0] == type; } static void ip6_send_ns(struct in6_addr *neigh_addr) { struct in6_addr dst_adr; unsigned char enetaddr[6]; struct nd_msg *msg; __u16 len; uchar *pkt; unsigned short csum; unsigned int pcsum; debug("sending neighbor solicitation for %pI6c our address %pI6c\n", neigh_addr, &net_link_local_ip6); /* calculate src, dest IPv6 addr and dest Eth addr */ ip6_make_snma(&dst_adr, neigh_addr); ip6_make_mult_ethdstaddr(enetaddr, &dst_adr); len = sizeof(struct icmp6hdr) + IN6ADDRSZ + IP6_NDISC_OPT_SPACE(INETHADDRSZ); pkt = (uchar *)net_tx_packet; pkt += net_set_ether(pkt, enetaddr, PROT_IP6); pkt += ip6_add_hdr(pkt, &net_link_local_ip6, &dst_adr, PROT_ICMPV6, IPV6_NDISC_HOPLIMIT, len); /* ICMPv6 - NS */ msg = (struct nd_msg *)pkt; msg->icmph.icmp6_type = IPV6_NDISC_NEIGHBOUR_SOLICITATION; msg->icmph.icmp6_code = 0; memset(&msg->icmph.icmp6_cksum, 0, sizeof(__be16)); memset(&msg->icmph.icmp6_unused, 0, sizeof(__be32)); /* Set the target address and llsaddr option */ net_copy_ip6(&msg->target, neigh_addr); ndisc_insert_option(msg, ND_OPT_SOURCE_LL_ADDR, net_ethaddr, INETHADDRSZ); /* checksum */ pcsum = csum_partial((__u8 *)msg, len, 0); csum = csum_ipv6_magic(&net_link_local_ip6, &dst_adr, len, PROT_ICMPV6, pcsum); msg->icmph.icmp6_cksum = csum; pkt += len; /* send it! */ net_send_packet(net_tx_packet, (pkt - net_tx_packet)); } static void ip6_send_na(uchar *eth_dst_addr, struct in6_addr *neigh_addr, struct in6_addr *target) { struct nd_msg *msg; __u16 len; uchar *pkt; unsigned short csum; debug("sending neighbor advertisement for %pI6c to %pI6c (%pM)\n", target, neigh_addr, eth_dst_addr); len = sizeof(struct icmp6hdr) + IN6ADDRSZ + IP6_NDISC_OPT_SPACE(INETHADDRSZ); pkt = (uchar *)net_tx_packet; pkt += net_set_ether(pkt, eth_dst_addr, PROT_IP6); pkt += ip6_add_hdr(pkt, &net_link_local_ip6, neigh_addr, PROT_ICMPV6, IPV6_NDISC_HOPLIMIT, len); /* ICMPv6 - NA */ msg = (struct nd_msg *)pkt; msg->icmph.icmp6_type = IPV6_NDISC_NEIGHBOUR_ADVERTISEMENT; msg->icmph.icmp6_code = 0; memset(&msg->icmph.icmp6_cksum, 0, sizeof(__be16)); memset(&msg->icmph.icmp6_unused, 0, sizeof(__be32)); msg->icmph.icmp6_dataun.u_nd_advt.solicited = 1; msg->icmph.icmp6_dataun.u_nd_advt.override = 1; /* Set the target address and lltargetaddr option */ net_copy_ip6(&msg->target, target); ndisc_insert_option(msg, ND_OPT_TARGET_LL_ADDR, net_ethaddr, INETHADDRSZ); /* checksum */ csum = csum_ipv6_magic(&net_link_local_ip6, neigh_addr, len, PROT_ICMPV6, csum_partial((__u8 *)msg, len, 0)); msg->icmph.icmp6_cksum = csum; pkt += len; /* send it! */ net_send_packet(net_tx_packet, (pkt - net_tx_packet)); } void ndisc_request(void) { if (!ip6_addr_in_subnet(&net_ip6, &net_nd_sol_packet_ip6, net_prefix_length)) { if (ip6_is_unspecified_addr(&net_gateway6)) { puts("## Warning: gatewayip6 is needed but not set\n"); net_nd_rep_packet_ip6 = net_nd_sol_packet_ip6; } else { net_nd_rep_packet_ip6 = net_gateway6; } } else { net_nd_rep_packet_ip6 = net_nd_sol_packet_ip6; } ip6_send_ns(&net_nd_rep_packet_ip6); } int ndisc_timeout_check(void) { ulong t; if (ip6_is_unspecified_addr(&net_nd_sol_packet_ip6)) return 0; t = get_timer(0); /* check for NDISC timeout */ if ((t - net_nd_timer_start) > NDISC_TIMEOUT) { net_nd_try++; if (net_nd_try >= NDISC_TIMEOUT_COUNT) { puts("\nNeighbour discovery retry count exceeded; " "starting again\n"); net_nd_try = 0; net_set_state(NETLOOP_FAIL); } else { net_nd_timer_start = t; ndisc_request(); } } return 1; } void ndisc_init(void) { net_nd_packet_mac = NULL; net_nd_tx_packet = NULL; net_nd_sol_packet_ip6 = net_null_addr_ip6; net_nd_rep_packet_ip6 = net_null_addr_ip6; net_nd_tx_packet_size = 0; net_nd_tx_packet = &net_nd_packet_buf[0] + (PKTALIGN - 1); net_nd_tx_packet -= (ulong)net_nd_tx_packet % PKTALIGN; } int ndisc_receive(struct ethernet_hdr *et, struct ip6_hdr *ip6, int len) { struct icmp6hdr *icmp = (struct icmp6hdr *)(((uchar *)ip6) + IP6_HDR_SIZE); struct nd_msg *ndisc = (struct nd_msg *)icmp; uchar neigh_eth_addr[6]; switch (icmp->icmp6_type) { case IPV6_NDISC_NEIGHBOUR_SOLICITATION: debug("received neighbor solicitation for %pI6c from %pI6c\n", &ndisc->target, &ip6->saddr); if (ip6_is_our_addr(&ndisc->target) && ndisc_has_option(ip6, ND_OPT_SOURCE_LL_ADDR)) { ndisc_extract_enetaddr(ndisc, neigh_eth_addr); ip6_send_na(neigh_eth_addr, &ip6->saddr, &ndisc->target); } break; case IPV6_NDISC_NEIGHBOUR_ADVERTISEMENT: /* are we waiting for a reply ? */ if (ip6_is_unspecified_addr(&net_nd_sol_packet_ip6)) break; if ((memcmp(&ndisc->target, &net_nd_rep_packet_ip6, sizeof(struct in6_addr)) == 0) && ndisc_has_option(ip6, ND_OPT_TARGET_LL_ADDR)) { ndisc_extract_enetaddr(ndisc, neigh_eth_addr); /* save address for later use */ if (!net_nd_packet_mac) net_nd_packet_mac = neigh_eth_addr; /* modify header, and transmit it */ memcpy(((struct ethernet_hdr *)net_nd_tx_packet)->et_dest, neigh_eth_addr, 6); net_send_packet(net_nd_tx_packet, net_nd_tx_packet_size); /* no ND request pending now */ net_nd_sol_packet_ip6 = net_null_addr_ip6; net_nd_tx_packet_size = 0; net_nd_packet_mac = NULL; } break; default: debug("Unexpected ICMPv6 type 0x%x\n", icmp->icmp6_type); return -1; } return 0; }