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cide_lookup()のインラインアセンブラバージョン

uint32_t half=0;
uint32_t csub=0;
uint32_t cmin=0;
uint32_t cmax=0;
uint32_t addr=0;
char *cidr_lookup(void *ipaddr, int len)
{
  if(len != 4)
    return(0);
  addr = ntohl(*(uint32_t *)ipaddr);
  asm volatile(
    "lookup_start:"
      "push %eax;"
      "push %ebx;"
      "push %ecx;"
      "push %edx;"
      "xor  %eax, %eax;"
      "movl %eax, cmin;"
      "movl listcount, %eax;"
      "movl %eax, cmax;"
      "movl %eax, csub;"
    "lookup_loop:"
      "shr  %eax;"
      "add  cmin, %eax;"
      "movl %eax, half;"
      "movl csub, %eax;"
      "cmp  $7, %eax;"
      "jb lookup_search;"
      "movl half, %eax;"
      "shl  $2, %eax;"
      "movl cidrlist, %edx;"
      "add  %eax, %edx;"
      "movl addr, %eax;"
      "cmp (%edx), %eax;"
      "jc lookup_low;"
    "lookup_high:"         /* addr > cidr */
      "movl half, %eax;"
      "movl %eax, cmin;"
      "jmp lookup_endif;"
    "lookup_low:"          /* addr < cidr */
      "movl half, %eax;"
      "movl %eax, cmax;"
    "lookup_endif:"
      "movl cmax, %eax;"
      "sub  cmin, %eax;"
      "movl %eax, csub;"
      "jmp lookup_loop;"
    "lookup_search:"
      "movl cmax, %ecx;"
      "sub  cmin, %ecx;"
      "movl cmax, %eax;"
      "dec  %eax;"
      "movl %eax, half;"
      "shl  $2, %eax;"
      "movl masklist, %ebx;"
      "movl cidrlist, %edx;"
      "add  %eax, %ebx;"
      "add  %eax, %edx;"
    "lookup_search_loop:"
      "movl (%ebx), %eax;"
      "and  addr, %eax;"
      "cmp  (%edx), %eax;"
      "je lookup_end;"     /* if(addr == cidr) */
      "sub  $4, %ebx;"
      "sub  $4, %edx;"
      "movl half, %eax;"
      "dec %eax;"
      "mov %eax, half;"
      "loop lookup_search_loop;"
      "movl $0xffffffff, %eax;"
      "movl %eax, half;"
    "lookup_end:"
      "pop %edx;"
      "pop %ecx;"
      "pop %ebx;"
      "pop %eax;"
  );
  if(half == -1)
    return(NULL);
  return(typelist[half]);
}

cidr_initialize()

#include <stdio.h>

#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>
#include <fcntl.h>
#include <libgen.h>

#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define DBDIR "../data"
uint32_t listsize  = 0;
uint32_t listcount = 0;
uint32_t *cidrlist = NULL;
uint32_t *masklist = NULL;
char    **typelist = NULL;

int getnetmask(int n, uint32_t *netmask)
{
  uint32_t h = 1;
  uint32_t m = 0xffffffff;
  if(n>32)
    return(0);
  n = 32 - n;
  while(n--){
    m -= h;
    h *= 2;
  }
  *netmask = m;
  return(1);
}

int initsort()
{
  int i;
  int j;
  uint32_t t;
  char   *tt;
  for(i=0;i cidrlist[j]){
        t = cidrlist[i];
        cidrlist[i] = cidrlist[j];
        cidrlist[j] = t;
        t = masklist[i];
        masklist[i] = masklist[j];
        masklist[j] = t;
        tt = typelist[i];
        typelist[i] = typelist[j];
        typelist[j] = tt;
      }
    }
  }
  for(i=1;i< masklist[j]){
        t = cidrlist[i];
        cidrlist[i] = cidrlist[j];
        cidrlist[j] = t;
        t = masklist[i];
        masklist[i] = masklist[j];
        masklist[j] = t;
        tt = typelist[i];
        typelist[i] = typelist[j];
        typelist[j] = tt;
      }
    }
  }
  return(0);
}

int initread(int fd, char *type)
{
  int  r;
  int  l;
  char buff[256];
  char *p = buff;
  uint32_t ad=0;
  uint32_t nm=0;
  char ip[64];

  while((r=read(fd,p,1)) != 0){
    if(r == -1)
      return(-1);
    if(*p == '#')
      *p = 0;
    if(*p == '/')
      *p = ' ';
    if(*p == '\r')
      *p = 0;
    if(*p == '\n'){
      *p = 0;
      l = 32;
      if(sscanf(buff,"%s%d", ip, &l) < 1){
        /***** not ip addr ******/
        if(buff[0]){
          fprintf(stderr,"read error: %s(%s/%d)\n",buff,ip,l);
        }
      }else{
        /*----- alloc -----*/
        if(listcount == listsize){
          listsize += 512;
          typelist = (char    **)realloc(typelist, listsize * sizeof(char *));
          cidrlist = (uint32_t *)realloc(cidrlist, listsize * sizeof(uint32_t));
          masklist = (uint32_t *)realloc(masklist, listsize * sizeof(uint32_t));
        }
        if(!inet_aton(ip, (struct in_addr *)&ad)){
          fprintf(stderr,"ip addr error: %s\n", buff);
        }
        if(!getnetmask(l,&nm)){
          fprintf(stderr,"netmask error: %s\n", buff);
        }
        ad  = ntohl(ad);
        ad &= nm;
        typelist[listcount] = type;
        cidrlist[listcount] = ad;
        masklist[listcount] = nm;
        listcount++;
      }
      p = buff;
      continue;
    }
    p++;
  }
  return(0);
}

char *alloctype(char *name)
{
  char *type;
  char *base;
  char path[PATH_MAX];
  strcpy(path, name);
  base=basename(path);
  type=malloc(strlen(base)+1);
  strcpy(type,base);
  return(type);
}

void cidr_initialize()
{
  int  f;
  DIR *d;
  char path[PATH_MAX];
  struct dirent *e;
  struct stat   st;
  if((d=opendir(DBDIR)) != 0){
    while((e=readdir(d)) != 0){
      sprintf(path,"%s/%s", DBDIR, e->d_name);
      if(stat(path, &st) != 0)
        continue;
      if(!S_ISREG(st.st_mode))
        continue;
      f = open(path, O_RDONLY);
      if(f == -1){
        fprintf(stderr,"file open error %s\n", path);
      }else{
        initread(f,alloctype(path));
        close(f);
      }
    }
  }
  initsort();
}