--- /dev/null
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+#include <net/if.h>
+#include <net/route.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "arg.h"
+#include "util.h"
+
+typedef struct bootp {
+ unsigned char op [1];
+ unsigned char htype [1];
+ unsigned char hlen [1];
+ unsigned char hops [1];
+ unsigned char xid [4];
+ unsigned char secs [2];
+ unsigned char flags [2];
+ unsigned char ciaddr [4];
+ unsigned char yiaddr [4];
+ unsigned char siaddr [4];
+ unsigned char giaddr [4];
+ unsigned char chaddr [16];
+ unsigned char sname [64];
+ unsigned char file [128];
+ unsigned char magic [4];
+ unsigned char optdata [312-4];
+} Bootp;
+
+enum {
+ DHCPdiscover = 1,
+ DHCPoffer,
+ DHCPrequest,
+ DHCPdecline,
+ DHCPack,
+ DHCPnak,
+ DHCPrelease,
+ DHCPinform,
+ Timeout = 200,
+
+ Bootrequest = 1,
+ Bootreply = 2,
+ /* bootp flags */
+ Fbroadcast = 1 << 15,
+
+ OBpad = 0,
+ OBmask = 1,
+ OBrouter = 3,
+ OBnameserver = 5,
+ OBdnsserver = 6,
+ OBbaddr = 28,
+ ODipaddr = 50, /* 0x32 */
+ ODlease = 51,
+ ODoverload = 52,
+ ODtype = 53, /* 0x35 */
+ ODserverid = 54, /* 0x36 */
+ ODparams = 55, /* 0x37 */
+ ODmessage = 56,
+ ODmaxmsg = 57,
+ ODrenewaltime = 58,
+ ODrebindingtime = 59,
+ ODvendorclass = 60,
+ ODclientid = 61, /* 0x3d */
+ ODtftpserver = 66,
+ ODbootfile = 67,
+ OBend = 255,
+};
+
+enum { Broadcast, Unicast};
+
+Bootp bp;
+unsigned char magic[] = {99, 130, 83, 99};
+
+/* conf */
+static unsigned char xid[sizeof bp.xid];
+static unsigned char hwaddr[16];
+static time_t starttime;
+static char *ifname = "eth0";
+static unsigned char cid[16];
+static char *program = "";
+static int sock;
+/* sav */
+static unsigned char server[4];
+static unsigned char client[4];
+static unsigned char mask[4];
+static unsigned char router[4];
+static unsigned char dns[4];
+static unsigned long t1;
+
+static int dflag = 1; /* change DNS in /etc/resolv.conf ? */
+static int iflag = 1; /* set IP ? */
+static int fflag = 0; /* run in foreground */
+
+#define IP(a,b,c,d) (unsigned char[4]){a,b,c,d}
+
+static void
+hnput(unsigned char *dst, unsigned long long src, size_t n)
+{
+ unsigned int i;
+
+ for (i = 0; n--; i++)
+ dst[i] = (src >> (n * 8)) & 0xff;
+}
+
+static struct sockaddr *
+iptoaddr(struct sockaddr *ifaddr, unsigned char ip[4], int port)
+{
+ struct sockaddr_in *in = (struct sockaddr_in *)ifaddr;
+
+ in->sin_family = AF_INET;
+ in->sin_port = htons(port);
+ memcpy(&(in->sin_addr), ip, sizeof in->sin_addr);
+
+ return ifaddr;
+}
+
+/* sendto UDP wrapper */
+static ssize_t
+udpsend(unsigned char ip[4], int fd, void *data, size_t n)
+{
+ struct sockaddr addr;
+ socklen_t addrlen = sizeof addr;
+ ssize_t sent;
+
+ iptoaddr(&addr, ip, 67); /* bootp server */
+ if ((sent = sendto(fd, data, n, 0, &addr, addrlen)) == -1)
+ eprintf("sendto:");
+
+ return sent;
+}
+
+/* recvfrom UDP wrapper */
+static ssize_t
+udprecv(unsigned char ip[4], int fd, void *data, size_t n)
+{
+ struct sockaddr addr;
+ socklen_t addrlen = sizeof addr;
+ ssize_t r;
+
+ iptoaddr(&addr, ip, 68); /* bootp client */
+ if ((r = recvfrom(fd, data, n, 0, &addr, &addrlen)) == -1)
+ eprintf("recvfrom:");
+
+ return r;
+}
+
+static void
+setip(unsigned char ip[4], unsigned char mask[4], unsigned char gateway[4])
+{
+ struct ifreq ifreq;
+ struct rtentry rtreq;
+ int fd;
+
+ memset(&ifreq, 0, sizeof(ifreq));
+ memset(&rtreq, 0, sizeof(rtreq));
+
+ strlcpy(ifreq.ifr_name, ifname, IF_NAMESIZE);
+ iptoaddr(&(ifreq.ifr_addr), ip, 0);
+ if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP)) == -1)
+ eprintf("can't set ip, socket:");
+ ioctl(fd, SIOCSIFADDR, &ifreq);
+ iptoaddr(&(ifreq.ifr_netmask), mask, 0);
+ ioctl(fd, SIOCSIFNETMASK, &ifreq);
+ ifreq.ifr_flags = IFF_UP | IFF_RUNNING | IFF_BROADCAST | IFF_MULTICAST;
+ ioctl(fd, SIOCSIFFLAGS, &ifreq);
+ /* gw */
+ rtreq.rt_flags = (RTF_UP | RTF_GATEWAY);
+ iptoaddr(&(rtreq.rt_gateway), gateway, 0);
+ iptoaddr(&(rtreq.rt_genmask), IP(0, 0, 0, 0), 0);
+ iptoaddr(&(rtreq.rt_dst), IP(0, 0, 0, 0), 0);
+ ioctl(fd, SIOCADDRT, &rtreq);
+
+ close(fd);
+}
+
+static void
+cat(int dfd, char *src)
+{
+ char buf[BUFSIZ];
+ int n, fd;
+
+ if ((fd = open(src, O_RDONLY)) == -1)
+ return; /* can't read, but don't error out */
+ while ((n = read(fd, buf, sizeof buf)) > 0)
+ write(dfd, buf, n);
+ close(fd);
+}
+
+static void
+setdns(unsigned char dns[4])
+{
+ char buf[128];
+ int fd;
+
+ if ((fd = creat("/etc/resolv.conf", 0644)) == -1) {
+ weprintf("can't change /etc/resolv.conf:");
+ return;
+ }
+ cat(fd, "/etc/resolv.conf.head");
+ if (snprintf(buf, sizeof(buf) - 1, "\nnameserver %d.%d.%d.%d\n",
+ dns[0], dns[1], dns[2], dns[3]) > 0)
+ write(fd, buf, strlen(buf));
+ cat(fd, "/etc/resolv.conf.tail");
+ close(fd);
+}
+
+static void
+optget(Bootp *bp, void *data, int opt, int n)
+{
+ unsigned char *p = bp->optdata;
+ unsigned char *top = ((unsigned char *)bp) + sizeof *bp;
+ int code, len;
+
+ while (p < top) {
+ code = *p++;
+ if (code == OBpad)
+ continue;
+ if (code == OBend || p == top)
+ break;
+ len = *p++;
+ if (len > top - p)
+ break;
+ if (code == opt) {
+ memcpy(data, p, MIN(len, n));
+ break;
+ }
+ p += len;
+ }
+}
+
+static unsigned char *
+optput(unsigned char *p, int opt, unsigned char *data, size_t len)
+{
+ *p++ = opt;
+ *p++ = (unsigned char)len;
+ memcpy(p, data, len);
+
+ return p + len;
+}
+
+static unsigned char *
+hnoptput(unsigned char *p, int opt, long long data, size_t len)
+{
+ *p++ = opt;
+ *p++ = (unsigned char)len;
+ hnput(p, data, len);
+
+ return p + len;
+}
+
+static void
+dhcpsend(int type, int how)
+{
+ unsigned char *ip, *p;
+
+ memset(&bp, 0, sizeof bp);
+ hnput(bp.op, Bootrequest, 1);
+ hnput(bp.htype, 1, 1);
+ hnput(bp.hlen, 6, 1);
+ memcpy(bp.xid, xid, sizeof xid);
+ hnput(bp.flags, Fbroadcast, sizeof bp.flags);
+ hnput(bp.secs, time(NULL) - starttime, sizeof bp.secs);
+ memcpy(bp.magic, magic, sizeof bp.magic);
+ memcpy(bp.chaddr, hwaddr, sizeof bp.chaddr);
+ p = bp.optdata;
+ p = hnoptput(p, ODtype, type, 1);
+ p = optput(p, ODclientid, cid, sizeof(cid));
+
+ switch(type) {
+ case DHCPdiscover:
+ break;
+ case DHCPrequest:
+ /* memcpy(bp.ciaddr, client, sizeof bp.ciaddr); */
+ p = hnoptput(p, ODlease, t1, sizeof t1);
+ p = optput(p, ODipaddr, client, sizeof client);
+ p = optput(p, ODserverid, server, sizeof server);
+ break;
+ case DHCPrelease:
+ memcpy(bp.ciaddr, client, sizeof client);
+ p = optput(p, ODipaddr, client, sizeof client);
+ p = optput(p, ODserverid, server, sizeof server);
+ break;
+ }
+ *p++ = OBend;
+
+ ip = (how == Broadcast) ? IP(255, 255, 255, 255) : server;
+ udpsend(ip, sock, &bp, p - (unsigned char *)&bp);
+}
+
+static int
+dhcprecv(void)
+{
+ unsigned char type;
+ struct pollfd pfd;
+
+ memset(&pfd, 0, sizeof(pfd));
+ pfd.fd = sock;
+ pfd.events = POLLIN;
+
+ memset(&bp, 0, sizeof bp);
+ if (poll(&pfd, 1, -1) == -1) {
+ if (errno != EINTR)
+ eprintf("poll:");
+ else
+ return Timeout;
+ }
+ udprecv(IP(255, 255, 255, 255), sock, &bp, sizeof bp);
+ optget(&bp, &type, ODtype, sizeof type);
+
+ return type;
+}
+
+static void
+acceptlease(void)
+{
+ char buf[128];
+
+ if (iflag)
+ setip(client, mask, router);
+ if (dflag)
+ setdns(dns);
+ if (*program) {
+ snprintf(buf, sizeof(buf), "%d.%d.%d.%d", server[0], server[1], server[2], server[3]);
+ setenv("SERVER", buf, 1);
+ snprintf(buf, sizeof(buf), "%d.%d.%d.%d", client[0], client[1], client[2], client[3]);
+ setenv("CLIENT", buf, 1);
+ snprintf(buf, sizeof(buf), "%d.%d.%d.%d", mask[0], mask[1], mask[2], mask[3]);
+ setenv("MASK", buf, 1);
+ snprintf(buf, sizeof(buf), "%d.%d.%d.%d", router[0], router[1], router[2], router[3]);
+ setenv("ROUTER", buf, 1);
+ snprintf(buf, sizeof(buf), "%d.%d.%d.%d", dns[0], dns[1], dns[2], dns[3]);
+ setenv("DNS", buf, 1);
+ system(program);
+ }
+ alarm(t1);
+}
+
+static void
+run(void)
+{
+ int forked = 0;
+
+Init:
+ dhcpsend(DHCPdiscover, Broadcast);
+ alarm(1);
+ goto Selecting;
+Selecting:
+ switch(dhcprecv()) {
+ case DHCPoffer:
+ alarm(0);
+ memcpy(client, bp.yiaddr, sizeof client);
+ optget(&bp, server, ODserverid, sizeof server);
+ optget(&bp, mask, OBmask, sizeof mask);
+ optget(&bp, router, OBrouter, sizeof router);
+ optget(&bp, dns, OBdnsserver, sizeof dns);
+ optget(&bp, &t1, ODlease, sizeof t1);
+ t1 = ntohl(t1);
+ dhcpsend(DHCPrequest, Broadcast);
+ goto Requesting;
+ case Timeout:
+ goto Init;
+ default:
+ goto Selecting;
+ }
+Requesting:
+ switch(dhcprecv()) {
+ case DHCPoffer:
+ goto Requesting; /* ignore other offers. */
+ case DHCPack:
+ acceptlease();
+ goto Bound;
+ }
+Bound:
+ fputs("Congrats! You should be on the 'net.\n", stdout);
+ if (!fflag && !forked) {
+ if (fork())
+ exit(0);
+ forked = 1;
+ }
+ switch (dhcprecv()) {
+ case DHCPoffer:
+ case DHCPack:
+ case DHCPnak:
+ goto Bound; /* discard offer, ACK or NAK */
+ case Timeout:
+ dhcpsend(DHCPrequest, Unicast);
+ goto Renewing;
+ }
+Renewing:
+ switch(dhcprecv()) {
+ case DHCPack:
+ acceptlease();
+ goto Bound;
+ case DHCPnak:
+ goto Init;
+ case Timeout:
+ dhcpsend(DHCPrequest, Broadcast);
+ goto Rebinding;
+ }
+Rebinding:
+ switch(dhcprecv()) {
+ case DHCPnak: /* lease expired */
+ goto Init;
+ case DHCPack:
+ acceptlease();
+ goto Bound;
+ }
+}
+
+static
+void nop(int unused)
+{
+ (void) unused;
+}
+
+static
+void cleanexit(int unused)
+{
+ (void) unused;
+ dhcpsend(DHCPrelease, Unicast);
+ exit(0);
+}
+
+static void
+usage(void)
+{
+ eprintf("usage: %s [-d] [-e program] [-f] [-i] [ifname] [clientid]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+ int bcast = 1;
+ struct ifreq ifreq;
+ struct sockaddr addr;
+ int rnd;
+
+ ARGBEGIN {
+ case 'd': /* don't update DNS in /etc/resolv.conf */
+ dflag = 0;
+ break;
+ case 'e': /* run program */
+ program = EARGF(usage());
+ break;
+ case 'f': /* run in foreground */
+ fflag = 1;
+ break;
+ case 'i': /* don't set ip */
+ iflag = 0;
+ break;
+ default:
+ usage();
+ break;
+ } ARGEND;
+
+ if (argc)
+ ifname = argv[0]; /* interface name */
+ if (argc >= 2)
+ strlcpy(cid, argv[1], sizeof(cid)); /* client-id */
+
+ memset(&ifreq, 0, sizeof(ifreq));
+ signal(SIGALRM, nop);
+ signal(SIGTERM, cleanexit);
+
+ if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+ eprintf("socket:");
+ if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &bcast, sizeof bcast) == -1)
+ eprintf("setsockopt:");
+
+ strlcpy(ifreq.ifr_name, ifname, IF_NAMESIZE);
+ ioctl(sock, SIOCGIFINDEX, &ifreq);
+ if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, &ifreq, sizeof ifreq) == -1)
+ eprintf("setsockopt:");
+ iptoaddr(&addr, IP(255, 255, 255, 255), 68);
+ if (bind(sock, (void*)&addr, sizeof addr) != 0)
+ eprintf("bind:");
+ ioctl(sock, SIOCGIFHWADDR, &ifreq);
+ memcpy(hwaddr, ifreq.ifr_hwaddr.sa_data, sizeof ifreq.ifr_hwaddr.sa_data);
+ if (!cid[0])
+ memcpy(cid, hwaddr, sizeof(cid));
+
+ if ((rnd = open("/dev/urandom", O_RDONLY)) == -1)
+ eprintf("can't open /dev/urandom to generate unique transaction identifier:");
+ read(rnd, xid, sizeof xid);
+ close(rnd);
+
+ starttime = time(NULL);
+ run();
+
+ return 0;
+}
projects / proto / albase.git / commitdiff