u-boot/net/net6.c
Ehsan Mohandesi 6de98b60ba net: ipv6: Add support for default gateway discovery.
In IPv6, the default gateway and prefix length are determined by receiving
a router advertisement as defined in -
https://www.rfc-editor.org/rfc/rfc4861.

Add support for sending router solicitation (RS) and processing router
advertisements (RA).

If the RA has prefix info option and following conditions are met, then
gatewayip6 and net_prefix_length of ip6addr env variables are initialized.
These are later consumed by IPv6 code for non-local destination IP.

- "Router Lifetime" != 0
- Prefix is NOT link-local prefix (0xfe80::/10)
- L flag is 1
- "Valid Lifetime" != 0

Timing Parameters:
- MAX_RTR_SOLICITATION_DELAY (0-1s)
- RTR_SOLICITATION_INTERVAL (4s) (min retransmit delay)
- MAX_RTR_SOLICITATIONS (3 RS transmissions)

The functionality is enabled by CONFIG_IPV6_ROUTER_DISCOVERY and invoked
automatically from net_init_loop().

Signed-off-by: Ehsan Mohandesi <emohandesi@linux.microsoft.com>
Tested-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>Reviewed-by:
Tested-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Reviewed-by: Viacheslav Mitrofanov <v.v.mitrofanov@yadro.com>
Tested-by: Sergei Antonov <saproj@gmail.com>
Reviewed-by: Sergei Antonov <saproj@gmail.com>
2023-05-05 17:58:52 -04:00

450 lines
10 KiB
C

// 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>
*/
/* Simple IPv6 network layer implementation */
#include <common.h>
#include <env_internal.h>
#include <malloc.h>
#include <net.h>
#include <net6.h>
#include <ndisc.h>
/* NULL IPv6 address */
struct in6_addr const net_null_addr_ip6 = ZERO_IPV6_ADDR;
/* Our gateway's IPv6 address */
struct in6_addr net_gateway6 = ZERO_IPV6_ADDR;
/* Our IPv6 addr (0 = unknown) */
struct in6_addr net_ip6 = ZERO_IPV6_ADDR;
/* Our link local IPv6 addr (0 = unknown) */
struct in6_addr net_link_local_ip6 = ZERO_IPV6_ADDR;
/* set server IPv6 addr (0 = unknown) */
struct in6_addr net_server_ip6 = ZERO_IPV6_ADDR;
/* The prefix length of our network */
u32 net_prefix_length;
bool use_ip6;
static int on_ip6addr(const char *name, const char *value, enum env_op op,
int flags)
{
char *mask;
size_t len;
if (flags & H_PROGRAMMATIC)
return 0;
if (op == env_op_delete) {
net_prefix_length = 0;
net_copy_ip6(&net_ip6, &net_null_addr_ip6);
return 0;
}
mask = strchr(value, '/');
if (mask) {
net_prefix_length = simple_strtoul(mask + 1, NULL, 10);
len = mask - value;
} else {
len = strlen(value);
}
return string_to_ip6(value, len, &net_ip6);
}
U_BOOT_ENV_CALLBACK(ip6addr, on_ip6addr);
static int on_gatewayip6(const char *name, const char *value, enum env_op op,
int flags)
{
if (flags & H_PROGRAMMATIC)
return 0;
return string_to_ip6(value, strlen(value), &net_gateway6);
}
U_BOOT_ENV_CALLBACK(gatewayip6, on_gatewayip6);
static int on_serverip6(const char *name, const char *value, enum env_op op,
int flags)
{
if (flags & H_PROGRAMMATIC)
return 0;
return string_to_ip6(value, strlen(value), &net_server_ip6);
}
U_BOOT_ENV_CALLBACK(serverip6, on_serverip6);
int ip6_is_unspecified_addr(struct in6_addr *addr)
{
return !(addr->s6_addr32[0] | addr->s6_addr32[1] |
addr->s6_addr32[2] | addr->s6_addr32[3]);
}
int ip6_is_our_addr(struct in6_addr *addr)
{
return !memcmp(addr, &net_link_local_ip6, sizeof(struct in6_addr)) ||
!memcmp(addr, &net_ip6, sizeof(struct in6_addr));
}
void ip6_make_eui(unsigned char eui[8], unsigned char const enetaddr[6])
{
memcpy(eui, enetaddr, 3);
memcpy(&eui[5], &enetaddr[3], 3);
eui[3] = 0xff;
eui[4] = 0xfe;
eui[0] ^= 2; /* "u" bit set to indicate global scope */
}
void ip6_make_lladdr(struct in6_addr *lladr, unsigned char const enetaddr[6])
{
unsigned char eui[8];
memset(lladr, 0, sizeof(struct in6_addr));
lladr->s6_addr16[0] = htons(IPV6_LINK_LOCAL_PREFIX);
ip6_make_eui(eui, enetaddr);
memcpy(&lladr->s6_addr[8], eui, 8);
}
void ip6_make_snma(struct in6_addr *mcast_addr, struct in6_addr *ip6_addr)
{
memset(mcast_addr, 0, sizeof(struct in6_addr));
mcast_addr->s6_addr[0] = 0xff;
mcast_addr->s6_addr[1] = IPV6_ADDRSCOPE_LINK;
mcast_addr->s6_addr[11] = 0x01;
mcast_addr->s6_addr[12] = 0xff;
mcast_addr->s6_addr[13] = ip6_addr->s6_addr[13];
mcast_addr->s6_addr[14] = ip6_addr->s6_addr[14];
mcast_addr->s6_addr[15] = ip6_addr->s6_addr[15];
}
void
ip6_make_mult_ethdstaddr(unsigned char enetaddr[6], struct in6_addr *mcast_addr)
{
enetaddr[0] = 0x33;
enetaddr[1] = 0x33;
memcpy(&enetaddr[2], &mcast_addr->s6_addr[12], 4);
}
int
ip6_addr_in_subnet(struct in6_addr *our_addr, struct in6_addr *neigh_addr,
u32 plen)
{
__be32 *addr_dwords;
__be32 *neigh_dwords;
addr_dwords = our_addr->s6_addr32;
neigh_dwords = neigh_addr->s6_addr32;
while (plen > 32) {
if (*addr_dwords++ != *neigh_dwords++)
return 0;
plen -= 32;
}
/* Check any remaining bits */
if (plen > 0) {
if ((*addr_dwords >> (32 - plen)) !=
(*neigh_dwords >> (32 - plen))) {
return 0;
}
}
return 1;
}
static inline unsigned int csum_fold(unsigned int sum)
{
sum = (sum & 0xffff) + (sum >> 16);
sum = (sum & 0xffff) + (sum >> 16);
/* Opaque moment. If reverse it to zero it will not be checked on
* receiver's side. It leads to bad negibour advertisement.
*/
if (sum == 0xffff)
return sum;
return ~sum;
}
static inline unsigned short from32to16(unsigned int x)
{
/* add up 16-bit and 16-bit for 16+c bit */
x = (x & 0xffff) + (x >> 16);
/* add up carry.. */
x = (x & 0xffff) + (x >> 16);
return x;
}
static u32 csum_do_csum(const u8 *buff, int len)
{
int odd;
unsigned int result = 0;
if (len <= 0)
goto out;
odd = 1 & (unsigned long)buff;
if (odd) {
#ifdef __LITTLE_ENDIAN
result += (*buff << 8);
#else
result = *buff;
#endif
len--;
buff++;
}
if (len >= 2) {
if (2 & (unsigned long)buff) {
result += *(unsigned short *)buff;
len -= 2;
buff += 2;
}
if (len >= 4) {
const unsigned char *end = buff + ((u32)len & ~3);
unsigned int carry = 0;
do {
unsigned int w = *(unsigned int *)buff;
buff += 4;
result += carry;
result += w;
carry = (w > result);
} while (buff < end);
result += carry;
result = (result & 0xffff) + (result >> 16);
}
if (len & 2) {
result += *(unsigned short *)buff;
buff += 2;
}
}
if (len & 1)
#ifdef __LITTLE_ENDIAN
result += *buff;
#else
result += (*buff << 8);
#endif
result = from32to16(result);
if (odd)
result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
out:
return result;
}
unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum)
{
unsigned int result = csum_do_csum(buff, len);
/* add in old sum, and carry.. */
result += sum;
/* 16+c bits -> 16 bits */
result = (result & 0xffff) + (result >> 16);
return result;
}
unsigned short int
csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, u16 len,
unsigned short proto, unsigned int csum)
{
int carry;
u32 ulen;
u32 uproto;
u32 sum = csum;
sum += saddr->s6_addr32[0];
carry = (sum < saddr->s6_addr32[0]);
sum += carry;
sum += saddr->s6_addr32[1];
carry = (sum < saddr->s6_addr32[1]);
sum += carry;
sum += saddr->s6_addr32[2];
carry = (sum < saddr->s6_addr32[2]);
sum += carry;
sum += saddr->s6_addr32[3];
carry = (sum < saddr->s6_addr32[3]);
sum += carry;
sum += daddr->s6_addr32[0];
carry = (sum < daddr->s6_addr32[0]);
sum += carry;
sum += daddr->s6_addr32[1];
carry = (sum < daddr->s6_addr32[1]);
sum += carry;
sum += daddr->s6_addr32[2];
carry = (sum < daddr->s6_addr32[2]);
sum += carry;
sum += daddr->s6_addr32[3];
carry = (sum < daddr->s6_addr32[3]);
sum += carry;
ulen = htonl((u32)len);
sum += ulen;
carry = (sum < ulen);
sum += carry;
uproto = htonl(proto);
sum += uproto;
carry = (sum < uproto);
sum += carry;
return csum_fold(sum);
}
int ip6_add_hdr(uchar *xip, struct in6_addr *src, struct in6_addr *dest,
int nextheader, int hoplimit, int payload_len)
{
struct ip6_hdr *ip6 = (struct ip6_hdr *)xip;
ip6->version = 6;
ip6->priority = 0;
ip6->flow_lbl[0] = 0;
ip6->flow_lbl[1] = 0;
ip6->flow_lbl[2] = 0;
ip6->payload_len = htons(payload_len);
ip6->nexthdr = nextheader;
ip6->hop_limit = hoplimit;
net_copy_ip6(&ip6->saddr, src);
net_copy_ip6(&ip6->daddr, dest);
return sizeof(struct ip6_hdr);
}
int net_send_udp_packet6(uchar *ether, struct in6_addr *dest, int dport,
int sport, int len)
{
uchar *pkt;
struct udp_hdr *udp;
u16 csum_p;
udp = (struct udp_hdr *)((uchar *)net_tx_packet + net_eth_hdr_size() +
IP6_HDR_SIZE);
udp->udp_dst = htons(dport);
udp->udp_src = htons(sport);
udp->udp_len = htons(len + UDP_HDR_SIZE);
/* checksum */
udp->udp_xsum = 0;
csum_p = csum_partial((u8 *)udp, len + UDP_HDR_SIZE, 0);
udp->udp_xsum = csum_ipv6_magic(&net_ip6, dest, len + UDP_HDR_SIZE,
IPPROTO_UDP, csum_p);
/* if MAC address was not discovered yet, save the packet and do
* neighbour discovery
*/
if (!memcmp(ether, net_null_ethaddr, 6)) {
net_copy_ip6(&net_nd_sol_packet_ip6, dest);
net_nd_packet_mac = ether;
pkt = net_nd_tx_packet;
pkt += net_set_ether(pkt, net_nd_packet_mac, PROT_IP6);
pkt += ip6_add_hdr(pkt, &net_ip6, dest, IPPROTO_UDP, 64,
len + UDP_HDR_SIZE);
memcpy(pkt, (uchar *)udp, len + UDP_HDR_SIZE);
/* size of the waiting packet */
net_nd_tx_packet_size = (pkt - net_nd_tx_packet) +
UDP_HDR_SIZE + len;
/* and do the neighbor solicitation */
net_nd_try = 1;
net_nd_timer_start = get_timer(0);
ndisc_request();
return 1; /* waiting */
}
pkt = (uchar *)net_tx_packet;
pkt += net_set_ether(pkt, ether, PROT_IP6);
pkt += ip6_add_hdr(pkt, &net_ip6, dest, IPPROTO_UDP, 64,
len + UDP_HDR_SIZE);
(void)eth_send(net_tx_packet, pkt - net_tx_packet + UDP_HDR_SIZE + len);
return 0; /* transmitted */
}
int net_ip6_handler(struct ethernet_hdr *et, struct ip6_hdr *ip6, int len)
{
struct in_addr zero_ip = {.s_addr = 0 };
struct icmp6hdr *icmp;
struct udp_hdr *udp;
u16 csum;
u16 csum_p;
u16 hlen;
if (len < IP6_HDR_SIZE)
return -EINVAL;
if (ip6->version != 6)
return -EINVAL;
switch (ip6->nexthdr) {
case PROT_ICMPV6:
icmp = (struct icmp6hdr *)(((uchar *)ip6) + IP6_HDR_SIZE);
csum = icmp->icmp6_cksum;
hlen = ntohs(ip6->payload_len);
icmp->icmp6_cksum = 0;
/* checksum */
csum_p = csum_partial((u8 *)icmp, hlen, 0);
icmp->icmp6_cksum = csum_ipv6_magic(&ip6->saddr, &ip6->daddr,
hlen, PROT_ICMPV6, csum_p);
if (icmp->icmp6_cksum != csum)
return -EINVAL;
switch (icmp->icmp6_type) {
case IPV6_ICMP_ECHO_REQUEST:
case IPV6_ICMP_ECHO_REPLY:
ping6_receive(et, ip6, len);
break;
case IPV6_NDISC_NEIGHBOUR_SOLICITATION:
case IPV6_NDISC_NEIGHBOUR_ADVERTISEMENT:
case IPV6_NDISC_ROUTER_ADVERTISEMENT:
ndisc_receive(et, ip6, len);
break;
default:
break;
}
break;
case IPPROTO_UDP:
udp = (struct udp_hdr *)(((uchar *)ip6) + IP6_HDR_SIZE);
csum = udp->udp_xsum;
hlen = ntohs(ip6->payload_len);
udp->udp_xsum = 0;
/* checksum */
csum_p = csum_partial((u8 *)udp, hlen, 0);
udp->udp_xsum = csum_ipv6_magic(&ip6->saddr, &ip6->daddr,
hlen, IPPROTO_UDP, csum_p);
if (csum != udp->udp_xsum)
return -EINVAL;
/* IP header OK. Pass the packet to the current handler. */
net_get_udp_handler()((uchar *)ip6 + IP6_HDR_SIZE +
UDP_HDR_SIZE,
ntohs(udp->udp_dst),
zero_ip,
ntohs(udp->udp_src),
ntohs(udp->udp_len) - 8);
break;
default:
return -EINVAL;
}
return 0;
}