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3 * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
4 * Copyright (c) 2008-2012, by Michael Tuexen. All rights reserved.
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7 * modification, are permitted provided that the following conditions are met:
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33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
39 #include <netinet/sctp_os.h>
40 #include <netinet/sctp.h>
41 #include <netinet/sctp_crc32.h>
42 #include <netinet/sctp_pcb.h>
44 #include <sys/param.h>
45 #include <sys/systm.h>
48 #include <netinet/sctp_crc32.h>
52 sctp_finalize_crc32c(uint32_t crc32c)
55 #if BYTE_ORDER == BIG_ENDIAN
56 uint8_t byte0, byte1, byte2, byte3;
59 /* Complement the result */
61 #if BYTE_ORDER == BIG_ENDIAN
63 * For BIG-ENDIAN platforms the result is in little-endian form. So
64 * we must swap the bytes to return the result in network byte
67 byte0 = result & 0x000000ff;
68 byte1 = (result >> 8) & 0x000000ff;
69 byte2 = (result >> 16) & 0x000000ff;
70 byte3 = (result >> 24) & 0x000000ff;
71 crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
74 * For LITTLE ENDIAN platforms the result is in already in network
83 * Compute the SCTP checksum in network byte order for a given mbuf chain m
84 * which contains an SCTP packet starting at offset.
85 * Since this function is also called by ipfw, don't assume that
86 * it is compiled on a kernel with SCTP support.
89 sctp_calculate_cksum(struct mbuf *m, uint32_t offset)
91 uint32_t base = 0xffffffff;
94 KASSERT(m != NULL, ("sctp_calculate_cksum, offset > length of mbuf chain"));
95 if (offset < (uint32_t)m->m_len) {
102 base = calculate_crc32c(base,
103 (unsigned char *)(m->m_data + offset),
104 (unsigned int)(m->m_len - offset));
108 base = calculate_crc32c(base,
109 (unsigned char *)m->m_data,
110 (unsigned int)m->m_len);
113 base = sctp_finalize_crc32c(base);
119 * Compute and insert the SCTP checksum in network byte order for a given
120 * mbuf chain m which contains an SCTP packet starting at offset.
123 sctp_delayed_cksum(struct mbuf *m, uint32_t offset)
127 checksum = sctp_calculate_cksum(m, offset);
128 SCTP_STAT_DECR(sctps_sendhwcrc);
129 SCTP_STAT_INCR(sctps_sendswcrc);
130 offset += offsetof(struct sctphdr, checksum);
132 if (offset + sizeof(uint32_t) > (uint32_t)(m->m_len)) {
134 panic("sctp_delayed_cksum(): m->m_len: %d, offset: %u.",
137 SCTP_PRINTF("sctp_delayed_cksum(): m->m_len: %d, offset: %u.\n",
142 *(uint32_t *)(m->m_data + offset) = checksum;