Hi Viacheslav,
On Tue, 30 Aug 2022 at 07:02, Viacheslav Mitrofanov
<v.v.mitrofa...@yadro.com> wrote:
>
> Functions that were exposed in "net: ipv6: Add IPv6 basic primitives"
> had only empty implementations and were exposed as API for futher
> patches. This patch add implementation of these functions. Main
> functions are: net_ip6_handler() - IPv6 packet handler for incoming
> packets; net_send_udp_packet6() - make up and send an UDP packet;
> csum_ipv6_magic() - compute checksum of IPv6 "psuedo-header" per RFC2460
> section 8.1; ip6_addr_in_subnet() - check if an address is in our
> subnet. Other functions are auxiliary.
>
> Signed-off-by: Viacheslav Mitrofanov <v.v.mitrofa...@yadro.com>
> ---
> include/net6.h | 36 ++++-
> net/net6.c | 380 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 415 insertions(+), 1 deletion(-)
>
> diff --git a/include/net6.h b/include/net6.h
> index 68fa38adbb..a7be2496d9 100644
> --- a/include/net6.h
> +++ b/include/net6.h
> @@ -180,12 +180,45 @@ extern bool use_ip6;
> #if IS_ENABLED(CONFIG_IPV6)
> /* Convert a string to an ipv6 address */
> int string_to_ip6(const char *s, struct in6_addr *addr);
> +
> +/* check that an IPv6 address is unspecified (zero) */
> +int ip6_is_unspecified_addr(struct in6_addr *addr);
> +/* check that an IPv6 address is ours */
> +int ip6_is_our_addr(struct in6_addr *addr);
> +/* check if neighbour is in the same subnet as us */
> +int ip6_addr_in_subnet(struct in6_addr *our_addr, struct in6_addr
> *neigh_addr,
> + u32 prefix_length);
> +
> +void ip6_make_lladdr(struct in6_addr *lladr, unsigned char const
> enetaddr[6]);
> +void ip6_make_snma(struct in6_addr *mcast_addr, struct in6_addr *ip6_addr);
> +void ip6_make_mult_ethdstaddr(unsigned char enetaddr[6],
> + struct in6_addr *mcast_addr);
> +
> +unsigned int csum_partial(const unsigned char *buff, int len, unsigned int
> sum);
> +unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
> + struct in6_addr *daddr, u16 len,
> + unsigned short proto, unsigned int csum);
Full comments on functions here please
> +
> +int ip6_add_hdr(uchar *xip, struct in6_addr *src, struct in6_addr *dest,
> + int nextheader, int hoplimit, int payload_len);
> +
> +/* Transmit UDP packet using IPv6, performing neighbour discovery if needed
> */
> +int net_send_udp_packet6(uchar *ether, struct in6_addr *dest,
> + int dport, int sport, int len);
> +
> +/* handler for incoming IPv6 echo packet */
> +void net_ip6_handler(struct ethernet_hdr *et, struct ip6_hdr *ip6,
> + int len);
> +
> +static inline void net_copy_ip6(void *to, const void *from)
> +{
> + memcpy((void *)to, from, sizeof(struct in6_addr));
> +}
> #else
> static inline int string_to_ip6(const char *s, struct in6_addr *addr)
> {
> return -1;
Make sure that error codes use -EINVAL etc.
> }
> -#endif
>
> static inline int ip6_is_unspecified_addr(struct in6_addr *addr)
> {
> @@ -257,5 +290,6 @@ net_ip6_handler(struct ethernet_hdr *et, struct ip6_hdr
> *ip6,
> static inline void net_copy_ip6(void *to, const void *from)
> {
> }
> +#endif
>
> #endif /* __NET6_H__ */
> diff --git a/net/net6.c b/net/net6.c
> index a0410ea8ba..0799d411b2 100644
> --- a/net/net6.c
> +++ b/net/net6.c
> @@ -16,6 +16,7 @@
> #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;
> @@ -98,3 +99,382 @@ static int on_serverip6(const char *name, const char
> *value, enum env_op op,
> }
>
> 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]) == 0;
return !(...)
> +}
> +
> +/**
> + * We have 2 addresses that we should respond to. A link
> + * local address and a global address. This returns true
> + * if the specified address matches either of these.
> + */
> +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;
lower-case hex
> + eui[0] ^= 2; /* "u" bit set to indicate global scope */
> +}
> +
> +void ip6_make_lladdr(struct in6_addr *lladr, unsigned char const enetaddr[6])
const unsigned char
> +{
> + uchar eui[8];
> +
> + memset(lladr, 0, sizeof(struct in6_addr));
'\0'
> + lladr->s6_addr16[0] = htons(IPV6_LINK_LOCAL_PREFIX);
> + ip6_make_eui(eui, enetaddr);
> + memcpy(&lladr->s6_addr[8], eui, 8);
> +}
> +
> +/*
> + * Given an IPv6 address generate an equivalent Solicited Node Multicast
> + * Address (SNMA) as described in RFC2461.
> + */
> +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];
> +}
> +
> +/*
> + * Given an IPv6 address generate the multicast MAC address that corresponds
> to
> + * it.
> + */
comment should go in header file if this is exported. Otherwise please
make static
> +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. */
Drop .
> + 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 for some reason.
Can you word wrap to 80cols? This seems a little short
> + */
> + 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) {
swap operands?
> + 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;
> +}
> +
> +/*
> + * Compute checksum of IPv6 "psuedo-header" per RFC2460 section 8.1
> + */
> +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;
> +
> + 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;
> + udp->udp_xsum = csum_ipv6_magic(&net_ip6, dest, len + UDP_HDR_SIZE,
> + IPPROTO_UDP,
> + csum_partial((u8 *)udp,
> + len + UDP_HDR_SIZE,
> + 0));
> +
> + /* if MAC address was not discovered yet, save the packet and do
> + * neighbour discovery
> + */
> + if (memcmp(ether, net_null_ethaddr, 6) == 0) {
!memcpy
> + 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 */
> +}
> +
> +void net_ip6_handler(struct ethernet_hdr *et, struct ip6_hdr *ip6, int len)
return an error code?
> +{
> + struct in_addr zero_ip = {.s_addr = 0 };
> + struct icmp6hdr *icmp;
> + struct udp_hdr *udp;
> + u16 csum;
> + u16 hlen;
> +
> + if (len < IP6_HDR_SIZE)
> + return;
> +
> + if (ip6->version != 6)
> + return;
> +
> + switch (ip6->nexthdr) {
> + case IPPROTO_ICMPV6:
> + icmp = (struct icmp6hdr *)(((uchar *)ip6) + IP6_HDR_SIZE);
> + csum = icmp->icmp6_cksum;
> + hlen = ntohs(ip6->payload_len);
> + icmp->icmp6_cksum = 0;
> + /* checksum */
> + icmp->icmp6_cksum = csum_ipv6_magic(&ip6->saddr, &ip6->daddr,
> + hlen, IPPROTO_ICMPV6,
> + csum_partial((u8 *)icmp,
> + hlen, 0));
> +
> + if (icmp->icmp6_cksum != csum)
> + return;
> +
> + switch (icmp->icmp6_type) {
> + case IPV6_NDISC_NEIGHBOUR_SOLICITATION:
> + case IPV6_NDISC_NEIGHBOUR_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 */
> + udp->udp_xsum = csum_ipv6_magic(&ip6->saddr, &ip6->daddr,
> + hlen, IPPROTO_UDP,
> + csum_partial((u8 *)udp,
> + hlen, 0));
can the csum_partial() call be done on the line before and put in a var?
> +
> + if (csum != udp->udp_xsum)
> + return;
> +
> + /* 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:
> + break;
> + }
> +}
> --
> 2.25.1
>
Regards,
Simon
