arif/xcat-core
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xcat-core/src/proxydhcp.c

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9.1 KiB
C
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#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdlib.h>
#include <errno.h>
#include <netinet/in.h>
#include <signal.h>
#include <syslog.h>
// the chunk size for each alloc
int chunknum = 200;
int doreload = 0;
int verbose = 0;
char logmsg[50];
// the struct to store the winpe configuration for each node
struct nodecfg {
char node[50];
char data[150];
};
char *data = NULL; // the ptr to the array of all node config
int nodenum = 0;
// trigger the main program to reload configuration file
void reload(int sig) {
doreload = 1;
}
// the subroutine which is used to load configuration from
// /var/lib/xcat/proxydhcp.cfg to *data
void loadcfg () {
nodenum = 0;
free(data);
data = NULL;
doreload = 0;
char *dp = NULL;
FILE *fp;
fp = fopen("/var/lib/xcat/proxydhcp.cfg", "r");
if (fp) {
int num = chunknum;
int rtime = 1;
while (num == chunknum) {
// realloc the chunknum size of memory each to save memory usage
data = realloc(data, sizeof(struct nodecfg) * chunknum * rtime);
if (NULL == data) {
fprintf (stderr, "Cannot get enough memory.\n");
free (data);
return;
}
dp = data + sizeof(struct nodecfg) * chunknum * (rtime - 1);
memset(dp, 0, sizeof(struct nodecfg) * chunknum);
num = fread(dp, sizeof (struct nodecfg), chunknum, fp);
nodenum += num;
rtime++;
}
fclose(fp);
}
}
// get the path of winpe from configuration file which is stored in *data
char *getwinpepath(char *node) {
int i;
struct nodecfg *nc = (struct nodecfg *)data;
for (i=0; i<nodenum;i++) {
if (0 == strcmp(nc->node, node)) {
return nc->data;
}
nc++;
}
return NULL;
}
int main(int argc, char *argv[]) {
int i;
for(i = 0; i < argc; i++)
{
if (strcmp(argv[i], "-V") == 0) {
verbose = 1;
setlogmask(LOG_UPTO(LOG_DEBUG));
openlog("proxydhcp", LOG_NDELAY, LOG_LOCAL0);
}
}
// regist my pid to /var/run/xcat/proxydhcp.pid
int pid = getpid();
FILE *pidf = fopen ("/var/run/xcat/proxydhcp.pid", "w");
if (pidf) {
fprintf(pidf, "%d", pid);
fclose (pidf);
} else {
fprintf (stderr, "Cannot open /var/run/xcat/proxydhcp.pid\n");
return 1;
}
// load configuration at first start
loadcfg();
// regist signal SIGUSR1 for triggering reload configuration from outside
struct sigaction sigact;
sigact.sa_handler = &reload;
sigaction(SIGUSR1, &sigact, NULL);
int serverfd,port;
int getpktinfo = 1;
struct addrinfo hint, *res;
char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
char clientpacket[1024];
struct sockaddr_in clientaddr;
struct msghdr msg;
struct cmsghdr *cmsgptr;
struct iovec iov[1];
unsigned int myip, clientip;
char *txtptr;
iov[0].iov_base = clientpacket;
iov[0].iov_len = 1024;
memset(&msg,0,sizeof(msg));
memset(&clientaddr,0,sizeof(clientaddr));
msg.msg_name=&clientaddr;
msg.msg_namelen = sizeof(clientaddr);
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control=&cmsg;
msg.msg_controllen = sizeof(cmsg);
char defaultwinpe[20] = "Boot/bootmgfw.efi";
char bootpmagic[4] = {0x63,0x82,0x53,0x63};
int pktsize;
int doexit=0;
port = 4011;
memset(&hint,0,sizeof(hint));
hint.ai_family = PF_INET; /* Would've done UNSPEC, but it doesn't work right and this is heavily v4 specific anyway */
hint.ai_socktype = SOCK_DGRAM;
hint.ai_flags = AI_PASSIVE;
getaddrinfo(NULL,"4011",&hint,&res);
serverfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (!serverfd) { fprintf(stderr,"That's odd...\n"); }
setsockopt(serverfd,IPPROTO_IP,IP_PKTINFO,&getpktinfo,sizeof(getpktinfo));
if (bind(serverfd,res->ai_addr ,res->ai_addrlen) < 0) {
fprintf(stderr,"Unable to bind 4011");
exit(1);
}
while (!doexit) {
// use select to wait for the 4011 request packages coming
fd_set fds;
FD_ZERO(&fds);
FD_SET(serverfd, &fds);
struct timeval timeout;
timeout.tv_sec = 30;
timeout.tv_usec = 0;
int rc;
if ((rc = select(serverfd+1,&fds,0,0, &timeout)) <= 0) {
if (doreload) {
loadcfg();
fprintf(stderr, "load in select\n");
}
if (verbose) {syslog(LOG_DEBUG, "reload /var/lib/xcat/proxydhcp.cfg\n");}
continue;
}
if (doreload) {
loadcfg();
if (verbose) {syslog(LOG_DEBUG, "reload /var/lib/xcat/proxydhcp.cfg\n");}
}
pktsize = recvmsg(serverfd,&msg,0);
if (pktsize < 320) {
continue;
}
if (clientpacket[0] != 1 || memcmp(clientpacket+0xec,bootpmagic,4)) {
continue;
}
for (cmsgptr = CMSG_FIRSTHDR(&msg); cmsgptr != NULL; cmsgptr = CMSG_NXTHDR(&msg,cmsgptr)) {
if (cmsgptr->cmsg_level == IPPROTO_IP && cmsgptr->cmsg_type == IP_PKTINFO) {
myip = ((struct in_pktinfo*)(CMSG_DATA(cmsgptr)))->ipi_addr.s_addr;
}
}
// get the ip of dhcp client
clientip = 0;
int i;
for (i = 0; i< 4; i++) {
clientip = clientip << 8;
clientip += (unsigned char)clientpacket[15-i];
}
// get the winpe path
struct hostent *host = gethostbyaddr(&clientip, sizeof(clientip), AF_INET);
char *winpepath = defaultwinpe;
if (host) {
if (host->h_name) {
// remove the domain part from hostname
char *place = strstr(host->h_name, ".");
if (place) {
*place = '\0';
}
winpepath = getwinpepath(host->h_name);
if (winpepath == NULL) {
winpepath = defaultwinpe;
}
if (verbose) {
sprintf(logmsg, "Received proxydhcp request from %s\n", host->h_name);
syslog(LOG_DEBUG, logmsg);
}
}
} else {
winpepath = defaultwinpe;
}
// get the Vendor class identifier
char *arch = NULL;
unsigned char *p = clientpacket + 0xf0;
while (*p != 0xff && p < (unsigned char *)clientpacket + pktsize) {
if (*p == 60) {
arch = p + 0x11;
break;
} else {
p += *(p+1) + 2;
}
}
char winboot[50]; // the bootload of winpe
memset(winboot, 0, 50);
if (0 == memcmp(arch, "00000", 5)) { // bios boot mode
strcpy(winboot, winpepath);
strcat(winboot, "Boot/pxeboot.0");
} else if (0 == memcmp(arch, "00007", 5)) { // uefi boot mode
strcpy(winboot, winpepath);
strcat(winboot, "Boot/bootmgfw.efi");
}
clientpacket[0] = 2; //change to a reply
myip = htonl(myip); //endian neutral change
clientpacket[0x14] = (myip>>24)&0xff; //maybe don't need to do this, maybe assigning the whole int would be better
clientpacket[0x15] = (myip>>16)&0xff;
clientpacket[0x16] = (myip>>8)&0xff;
clientpacket[0x17] = (myip)&0xff;
txtptr = clientpacket+0x6c;
strncpy(txtptr, winboot ,128); // keeping 128 in there just in case someone changes the string
//strncpy(txtptr,"winboot/new/Boot/bootmgfw.efi",128); // keeping 128 in there just in case someone changes the string
//strncpy(txtptr,"Boot/pxeboot.0",128); // keeping 128 in there just in case someone changes the string
clientpacket[0xf0]=0x35; //DHCP MSG type
clientpacket[0xf1]=0x1; // LEN of 1
clientpacket[0xf2]=0x5; //DHCP ACK
clientpacket[0xf3]=0x36; //DHCP server identifier
clientpacket[0xf4]=0x4; //DHCP server identifier length
clientpacket[0xf5] = (myip>>24)&0xff; //maybe don't need to do this, maybe assigning the whole int would be better
clientpacket[0xf6] = (myip>>16)&0xff;
clientpacket[0xf7] = (myip>>8)&0xff;
clientpacket[0xf8] = (myip)&0xff;
char winBCD[50];
strcpy(winBCD, winpepath);
strcat(winBCD, "Boot/BCD");
clientpacket[0xf9] = 0xfc; // dhcp 252 'proxy', but coopeted by bootmgfw, it's actually suggesting the boot config file
clientpacket[0xfa] = strlen(winBCD) + 1; //length of 9
txtptr = clientpacket+0xfb;
strncpy(txtptr, winBCD, strlen(winBCD));
clientpacket[0xfa + strlen(winBCD) + 1] = 0;
clientpacket[0xfa + strlen(winBCD) + 2] = 0xff;
sendto(serverfd,clientpacket,pktsize,0,(struct sockaddr*)&clientaddr,sizeof(clientaddr));
if (verbose) {
sprintf(logmsg, "Path of bootloader:%s. Path of BCD:%s\n", winboot, winBCD);
syslog(LOG_DEBUG, logmsg);
}
}
if (verbose) { closelog();}
}
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