Add helper functions to calculate the standard ethernet CRC in
little/big endian fashion, so that network drivers can just reference the standard implementation and don't have to bring their own. As discussed on arch@. Obtained from: NetBSD
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59ee11bbbe
commit
16b4a34316
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=130015
@ -350,6 +350,8 @@ struct mbuf;
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struct rtentry;
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struct sockaddr;
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extern uint32_t ether_crc32_le(const uint8_t *, size_t);
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extern uint32_t ether_crc32_be(const uint8_t *, size_t);
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extern void ether_demux(struct ifnet *, struct mbuf *);
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extern void ether_ifattach(struct ifnet *, const u_int8_t *);
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extern void ether_ifdetach(struct ifnet *);
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@ -879,6 +879,79 @@ SYSCTL_NODE(_net_link, IFT_ETHER, ether, CTLFLAG_RW, 0, "Ethernet");
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SYSCTL_INT(_net_link_ether, OID_AUTO, ipfw, CTLFLAG_RW,
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ðer_ipfw,0,"Pass ether pkts through firewall");
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#if 0
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/*
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* This is for reference. We have a table-driven version
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* of the little-endian crc32 generator, which is faster
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* than the double-loop.
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*/
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uint32_t
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ether_crc32_le(const uint8_t *buf, size_t len)
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{
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size_t i;
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uint32_t crc;
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int bit;
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uint8_t data;
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crc = 0xffffffff; /* initial value */
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for (i = 0; i < len; i++) {
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for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1)
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carry = (crc ^ data) & 1;
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crc >>= 1;
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if (carry)
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crc = (crc ^ ETHER_CRC_POLY_LE);
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}
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return (crc);
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}
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#else
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uint32_t
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ether_crc32_le(const uint8_t *buf, size_t len)
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{
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static const uint32_t crctab[] = {
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0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
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0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
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0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
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};
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size_t i;
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uint32_t crc;
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crc = 0xffffffff; /* initial value */
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for (i = 0; i < len; i++) {
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crc ^= buf[i];
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crc = (crc >> 4) ^ crctab[crc & 0xf];
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crc = (crc >> 4) ^ crctab[crc & 0xf];
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}
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return (crc);
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}
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#endif
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uint32_t
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ether_crc32_be(const uint8_t *buf, size_t len)
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{
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size_t i;
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uint32_t crc, carry;
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int bit;
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uint8_t data;
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crc = 0xffffffff; /* initial value */
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for (i = 0; i < len; i++) {
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for (data = *buf++, bit = 0; bit < 8; bit++, data >>= 1) {
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carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
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crc <<= 1;
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if (carry)
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crc = (crc ^ ETHER_CRC_POLY_BE) | carry;
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}
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}
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return (crc);
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}
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int
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ether_ioctl(struct ifnet *ifp, int command, caddr_t data)
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{
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