72 lines
1.3 KiB
C
72 lines
1.3 KiB
C
/*
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* Copyright 1990 Silicon Graphics, Inc. All rights reserved.
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*
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* Internet Protocol checksum routines.
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*/
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#include <sys/types.h>
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#include "protocols/ip.h"
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static u_long
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ip_partialsum(char *p, int len)
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{
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u_long sum;
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u_short *sp;
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sum = 0;
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if (len & 01) {
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p[len] = 0;
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len++;
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}
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len /= 2;
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for (sp = (u_short *) p; --len >= 0; sp++)
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sum += *sp;
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return sum;
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}
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int
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ip_checksum(char *p, int len, u_short *rsum)
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{
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u_long sum;
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if ((unsigned long)p & 01)
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return 0;
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sum = ip_partialsum(p, len);
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*rsum = IP_FOLD_CHECKSUM_CARRY(sum);
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return 1;
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}
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int
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ip_checksum_frame(struct ipframe *ipf, char *p, int len, u_short *rsum)
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{
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if (len != ipf->ipf_len - ipf->ipf_hdrlen)
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return 0;
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return ip_checksum(p, len, rsum);
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}
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struct pseudohdr {
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struct in_addr src;
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struct in_addr dst;
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u_char zero;
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u_char p;
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u_short len;
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};
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int
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ip_checksum_pseudohdr(struct ipframe *ipf, char *p, int len, u_short *rsum)
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{
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struct pseudohdr ph;
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u_long sum;
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if (len != ipf->ipf_len - ipf->ipf_hdrlen)
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return 0;
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ph.src.s_addr = htonl(ipf->ipf_src.s_addr);
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ph.dst.s_addr = htonl(ipf->ipf_rdst.s_addr);
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ph.zero = 0;
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ph.p = ipf->ipf_prototype;
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ph.len = len;
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sum = ip_partialsum((char *) &ph, sizeof ph);
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sum += ip_partialsum(p, len);
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*rsum = IP_FOLD_CHECKSUM_CARRY(sum);
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return 1;
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}
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