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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (C) 2013 Allied Telesis Labs NZ
- * Chris Packham, <judge.packham@gmail.com>
- *
- * Copyright (C) 2022 YADRO
- * Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
- */
- /* Neighbour Discovery for IPv6 */
- #include <common.h>
- #include <net.h>
- #include <net6.h>
- #include <ndisc.h>
- #include <stdlib.h>
- #include <linux/delay.h>
- /* 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;
- struct in6_addr all_routers = ALL_ROUTERS_MULT_ADDR;
- #define MAX_RTR_SOLICITATIONS 3
- /* The maximum time to delay sending the first router solicitation message. */
- #define MAX_SOLICITATION_DELAY 1 // 1 second
- /* The time to wait before sending the next router solicitation message. */
- #define RTR_SOLICITATION_INTERVAL 4000 // 4 seconds
- #define IP6_NDISC_OPT_SPACE(len) (((len) + 2 + 7) & ~7)
- /**
- * ndisc_insert_option() - Insert an option into a neighbor discovery packet
- *
- * @opt: pointer to the option element of the neighbor discovery 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(__u8 *opt, int type, u8 *data, int len)
- {
- int space = IP6_NDISC_OPT_SPACE(len);
- opt[0] = type;
- opt[1] = space >> 3;
- memcpy(&opt[2], data, len);
- len += 2;
- /* fill the remainder with 0 */
- if (space - len > 0)
- memset(&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->opt, 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));
- }
- /*
- * ip6_send_rs() - Send IPv6 Router Solicitation Message.
- *
- * A router solicitation is sent to discover a router. RS message creation is
- * based on RFC 4861 section 4.1. Router Solicitation Message Format.
- */
- void ip6_send_rs(void)
- {
- unsigned char enetaddr[6];
- struct rs_msg *msg;
- __u16 icmp_len;
- uchar *pkt;
- unsigned short csum;
- unsigned int pcsum;
- static unsigned int retry_count;
- if (!ip6_is_unspecified_addr(&net_gateway6) &&
- net_prefix_length != 0) {
- net_set_state(NETLOOP_SUCCESS);
- return;
- } else if (retry_count >= MAX_RTR_SOLICITATIONS) {
- net_set_state(NETLOOP_FAIL);
- net_set_timeout_handler(0, NULL);
- retry_count = 0;
- return;
- }
- printf("ROUTER SOLICITATION %d\n", retry_count + 1);
- ip6_make_mult_ethdstaddr(enetaddr, &all_routers);
- /*
- * ICMP length is the size of ICMP header (8) + one option (8) = 16.
- * The option is 2 bytes of type and length + 6 bytes for MAC.
- */
- icmp_len = sizeof(struct icmp6hdr) + 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, &all_routers, PROT_ICMPV6,
- IPV6_NDISC_HOPLIMIT, icmp_len);
- /* ICMPv6 - RS */
- msg = (struct rs_msg *)pkt;
- msg->icmph.icmp6_type = IPV6_NDISC_ROUTER_SOLICITATION;
- msg->icmph.icmp6_code = 0;
- memset(&msg->icmph.icmp6_cksum, 0, sizeof(__be16));
- memset(&msg->icmph.icmp6_unused, 0, sizeof(__be32));
- /* Set the llsaddr option */
- ndisc_insert_option(msg->opt, ND_OPT_SOURCE_LL_ADDR, net_ethaddr,
- INETHADDRSZ);
- /* checksum */
- pcsum = csum_partial((__u8 *)msg, icmp_len, 0);
- csum = csum_ipv6_magic(&net_link_local_ip6, &all_routers,
- icmp_len, PROT_ICMPV6, pcsum);
- msg->icmph.icmp6_cksum = csum;
- pkt += icmp_len;
- /* Wait up to 1 second if it is the first try to get the RA */
- if (retry_count == 0)
- udelay(((unsigned int)rand() % 1000000) * MAX_SOLICITATION_DELAY);
- /* send it! */
- net_send_packet(net_tx_packet, (pkt - net_tx_packet));
- retry_count++;
- net_set_timeout_handler(RTR_SOLICITATION_INTERVAL, ip6_send_rs);
- }
- 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->opt, 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;
- }
- /*
- * ndisc_init() - Make initial steps for ND state machine.
- * Usually move variables into initial state.
- */
- 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;
- }
- /*
- * validate_ra() - Validate the router advertisement message.
- *
- * @ip6: Pointer to the router advertisement packet
- *
- * Check if the router advertisement message is valid. Conditions are
- * according to RFC 4861 section 6.1.2. Validation of Router Advertisement
- * Messages.
- *
- * Return: true if the message is valid and false if it is invalid.
- */
- bool validate_ra(struct ip6_hdr *ip6)
- {
- struct icmp6hdr *icmp = (struct icmp6hdr *)(ip6 + 1);
- /* ICMP length (derived from the IP length) should be 16 or more octets. */
- if (ip6->payload_len < 16)
- return false;
- /* Source IP Address should be a valid link-local address. */
- if ((ntohs(ip6->saddr.s6_addr16[0]) & IPV6_LINK_LOCAL_MASK) !=
- IPV6_LINK_LOCAL_PREFIX)
- return false;
- /*
- * The IP Hop Limit field should have a value of 255, i.e., the packet
- * could not possibly have been forwarded by a router.
- */
- if (ip6->hop_limit != 255)
- return false;
- /* ICMP checksum has already been checked in net_ip6_handler. */
- if (icmp->icmp6_code != 0)
- return false;
- return true;
- }
- /*
- * process_ra() - Process the router advertisement packet.
- *
- * @ip6: Pointer to the router advertisement packet
- * @len: Length of the router advertisement packet
- *
- * Process the received router advertisement message.
- * Although RFC 4861 requires retaining at least two router addresses, we only
- * keep one because of the U-Boot limitations and its goal of lightweight code.
- *
- * Return: 0 - RA is a default router and contains valid prefix information.
- * Non-zero - RA options are invalid or do not indicate it is a default router
- * or do not contain valid prefix information.
- */
- int process_ra(struct ip6_hdr *ip6, int len)
- {
- /* Pointer to the ICMP section of the packet */
- struct icmp6hdr *icmp = (struct icmp6hdr *)(ip6 + 1);
- struct ra_msg *msg = (struct ra_msg *)icmp;
- int remaining_option_len = len - IP6_HDR_SIZE - sizeof(struct ra_msg);
- unsigned short int option_len; /* Length of each option */
- /* Pointer to the ICMPv6 message options */
- unsigned char *option = NULL;
- /* 8-bit identifier of the type of ICMPv6 option */
- unsigned char type = 0;
- struct icmp6_ra_prefix_info *prefix = NULL;
- if (len > ETH_MAX_MTU)
- return -EMSGSIZE;
- /* Ignore the packet if router lifetime is 0. */
- if (!icmp->icmp6_rt_lifetime)
- return -EOPNOTSUPP;
- /* Processing the options */
- option = msg->opt;
- while (remaining_option_len > 0) {
- /* The 2nd byte of the option is its length. */
- option_len = option[1];
- /* All included options should have a positive length. */
- if (option_len == 0)
- return -EINVAL;
- type = option[0];
- /* All option types except Prefix Information are ignored. */
- switch (type) {
- case ND_OPT_SOURCE_LL_ADDR:
- case ND_OPT_TARGET_LL_ADDR:
- case ND_OPT_REDIRECT_HDR:
- case ND_OPT_MTU:
- break;
- case ND_OPT_PREFIX_INFO:
- prefix = (struct icmp6_ra_prefix_info *)option;
- /* The link-local prefix 0xfe80::/10 is ignored. */
- if ((ntohs(prefix->prefix.s6_addr16[0]) &
- IPV6_LINK_LOCAL_MASK) == IPV6_LINK_LOCAL_PREFIX)
- break;
- if (prefix->on_link && ntohl(prefix->valid_lifetime)) {
- net_prefix_length = prefix->prefix_len;
- net_gateway6 = ip6->saddr;
- return 0;
- }
- break;
- default:
- debug("Unknown IPv6 Neighbor Discovery Option 0x%x\n",
- type);
- }
- option_len <<= 3; /* Option length is a multiple of 8. */
- remaining_option_len -= option_len;
- option += option_len;
- }
- return -EADDRNOTAVAIL;
- }
- 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];
- int err = 0; // The error code returned calling functions.
- 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;
- case IPV6_NDISC_ROUTER_SOLICITATION:
- break;
- case IPV6_NDISC_ROUTER_ADVERTISEMENT:
- debug("Received router advertisement for %pI6c from %pI6c\n",
- &ip6->daddr, &ip6->saddr);
- /*
- * If gateway and prefix are set, the RA packet is ignored. The
- * reason is that the U-Boot code is supposed to be as compact
- * as possible and does not need to take care of multiple
- * routers. In addition to that, U-Boot does not want to handle
- * scenarios like a router setting its lifetime to zero to
- * indicate it is not routing anymore. U-Boot program has a
- * short life when the system boots up and does not need such
- * sophistication.
- */
- if (!ip6_is_unspecified_addr(&net_gateway6) &&
- net_prefix_length != 0) {
- break;
- }
- if (!validate_ra(ip6)) {
- debug("Invalid router advertisement message.\n");
- break;
- }
- err = process_ra(ip6, len);
- if (err)
- debug("Ignored router advertisement. Error: %d\n", err);
- else
- printf("Set gatewayip6: %pI6c, prefix_length: %d\n",
- &net_gateway6, net_prefix_length);
- break;
- default:
- debug("Unexpected ICMPv6 type 0x%x\n", icmp->icmp6_type);
- return -1;
- }
- return 0;
- }
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