From 415c960b22b4084057577fc371510864378354dd Mon Sep 17 00:00:00 2001 From: Rob Landley Date: Wed, 14 Aug 2013 19:09:33 -0500 Subject: DHCP client and server, from Ashwini Sharma. --- toys/pending/dhcpd.c | 1247 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1247 insertions(+) create mode 100644 toys/pending/dhcpd.c (limited to 'toys/pending/dhcpd.c') diff --git a/toys/pending/dhcpd.c b/toys/pending/dhcpd.c new file mode 100644 index 00000000..18f4f25e --- /dev/null +++ b/toys/pending/dhcpd.c @@ -0,0 +1,1247 @@ +/* dhcpd.c - DHCP server for dynamic network configuration. + * + * Copyright 2013 Madhur Verma + * Copyright 2013 Kyungwan Han + * + * No Standard +USE_DHCPD(NEWTOY(dhcpd, ">1P#<0>65535=67fS", TOYFLAG_SBIN|TOYFLAG_ROOTONLY)) + +config DHCPD + bool "dhcpd" + default n + help + Usage: dhcpd [-fS] [-P N] [CONFFILE] + + -f Run in foreground + -S Log to syslog too + -P N Use port N (default 67) + +config DEBUG_DHCP + bool "debugging messeges ON/OFF" + default n + depends on DHCPD +*/ + +#define FOR_dhcpd + +#include "toys.h" +#include "toynet.h" +#include +#include + +// Todo: headers not in posix +#include +#include +#include + +#if CFG_DEBUG_DHCP==1 +# define dbg(fmt, arg...) printf(fmt, ##arg) +#else +# define dbg(fmt, arg...) +#endif + +#define flag_get(f,v,d) ((toys.optflags & (f)) ? (v) : (d)) +#define flag_chk(f) ((toys.optflags & (f)) ? 1 : 0) + +#define LOG_SILENT 0x0 +#define LOG_CONSOLE 0x1 +#define LOG_SYSTEM 0x2 + +#define DHCP_MAGIC 0x63825363 + +#define DHCPDISCOVER 1 +#define DHCPOFFER 2 +#define DHCPREQUEST 3 +#define DHCPDECLINE 4 +#define DHCPACK 5 +#define DHCPNAK 6 +#define DHCPRELEASE 7 +#define DHCPINFORM 8 + +#define DHCP_NUM8 (1<<8) +#define DHCP_NUM16 (1<<9) +#define DHCP_NUM32 DHCP_NUM16 | DHCP_NUM8 +#define DHCP_STRING (1<<10) +#define DHCP_STRLST (1<<11) +#define DHCP_IP (1<<12) +#define DHCP_IPLIST (1<<13) +#define DHCP_IPPLST (1<<14) +#define DHCP_STCRTS (1<<15) + +// DHCP option codes (partial list). See RFC 2132 and +#define DHCP_OPT_PADDING 0x00 +#define DHCP_OPT_HOST_NAME DHCP_STRING | 0x0c // either client informs server or server gives name to client +#define DHCP_OPT_REQUESTED_IP DHCP_IP | 0x32 // sent by client if specific IP is wanted +#define DHCP_OPT_LEASE_TIME DHCP_NUM32 | 0x33 +#define DHCP_OPT_OPTION_OVERLOAD 0x34 +#define DHCP_OPT_MESSAGE_TYPE DHCP_NUM8 | 0x35 +#define DHCP_OPT_SERVER_ID DHCP_IP | 0x36 // by default server's IP +#define DHCP_OPT_PARAM_REQ DHCP_STRING | 0x37 // list of options client wants +#define DHCP_OPT_END 0xff + +GLOBALS( + long port; +); + +typedef struct __attribute__((packed)) dhcp_msg_s { + uint8_t op; + uint8_t htype; + uint8_t hlen; + uint8_t hops; + uint32_t xid; + uint16_t secs; + uint16_t flags; + uint32_t ciaddr; + uint32_t yiaddr; + uint32_t nsiaddr; + uint32_t ngiaddr; + uint8_t chaddr[16]; + uint8_t sname[64]; + uint8_t file[128]; + uint32_t cookie; + uint8_t options[308]; +} dhcp_msg_t; + +typedef struct __attribute__((packed)) dhcp_raw_s { + struct iphdr iph; + struct udphdr udph; + dhcp_msg_t dhcp; +} dhcp_raw_t; + +typedef struct static_lease_s { + struct static_lease_s *next; + uint32_t nip; + int mac[6]; +} static_lease; + +typedef struct { + uint32_t expires; + uint32_t lease_nip; + uint8_t lease_mac[6]; + char hostname[20]; + uint8_t pad[2]; +} dyn_lease; + +typedef struct option_val_s { + char *key; + uint16_t code; + void *val; + size_t len; +} option_val_t; + +typedef struct __attribute__((__may_alias__)) server_config_s { + char *interface; // interface to use + int ifindex; + uint32_t server_nip; + uint32_t port; + uint8_t server_mac[6]; // our MAC address (used only for ARP probing) + void *options[256]; // list of DHCP options loaded from the config file + /* start,end are in host order: we need to compare start <= ip <= end*/ + uint32_t start_ip; // start address of leases, in host order + uint32_t end_ip; // end of leases, in host order + uint32_t max_lease_sec; // maximum lease time (host order) + uint32_t min_lease_sec; // minimum lease time a client can request + uint32_t max_leases; // maximum number of leases (including reserved addresses) + uint32_t auto_time; // how long should dhcpd wait before writing a config file. + // if this is zero, it will only write one on SIGUSR1 + uint32_t decline_time; // how long an address is reserved if a client returns a + // decline message + uint32_t conflict_time; // how long an arp conflict offender is leased for + uint32_t offer_time; // how long an offered address is reserved + uint32_t siaddr_nip; // "next server" bootp option + char *lease_file; + char *pidfile; + char *notify_file; // what to run whenever leases are written + char *sname; // bootp server name + char *boot_file; // bootp boot file option + struct static_lease *static_leases; // List of ip/mac pairs to assign static leases +} server_config_t; + +typedef struct __attribute__((__may_alias__)) server_state_s { + uint8_t rqcode; + int listensock; + dhcp_msg_t rcvd_pkt; + uint8_t* rqopt; + dhcp_msg_t send_pkt; + static_lease *sleases; + struct arg_list *dleases; +} server_state_t; + +struct config_keyword { + char *keyword; + int (*handler)(const char *str, void *var); + void *var; + char *def; +}; + +static option_val_t options_list[] = { + {"lease" , DHCP_NUM32 | 0x33, NULL, 0}, + {"subnet" , DHCP_IP | 0x01, NULL, 0}, + {"broadcast" , DHCP_IP | 0x1c, NULL, 0}, + {"router" , DHCP_IP | 0x03, NULL, 0}, + {"ipttl" , DHCP_NUM8 | 0x17, NULL, 0}, + {"mtu" , DHCP_NUM16 | 0x1a, NULL, 0}, + {"hostname" , DHCP_STRING | 0x0c, NULL, 0}, + {"domain" , DHCP_STRING | 0x0f, NULL, 0}, + {"search" , DHCP_STRLST | 0x77, NULL, 0}, + {"nisdomain" , DHCP_STRING | 0x28, NULL, 0}, + {"timezone" , DHCP_NUM32 | 0x02, NULL, 0}, + {"tftp" , DHCP_STRING | 0x42, NULL, 0}, + {"bootfile" , DHCP_STRING | 0x43, NULL, 0}, + {"bootsize" , DHCP_NUM16 | 0x0d, NULL, 0}, + {"rootpath" , DHCP_STRING | 0x11, NULL, 0}, + {"wpad" , DHCP_STRING | 0xfc, NULL, 0}, + {"serverid" , DHCP_IP | 0x36, NULL, 0}, + {"message" , DHCP_STRING | 0x38, NULL, 0}, + {"vlanid" , DHCP_NUM32 | 0x84, NULL, 0}, + {"vlanpriority" , DHCP_NUM32 | 0x85, NULL, 0}, + {"dns" , DHCP_IPLIST | 0x06, NULL, 0}, + {"wins" , DHCP_IPLIST | 0x2c, NULL, 0}, + {"nissrv" , DHCP_IPLIST | 0x29, NULL, 0}, + {"ntpsrv" , DHCP_IPLIST | 0x2a, NULL, 0}, + {"lprsrv" , DHCP_IPLIST | 0x09, NULL, 0}, + {"swapsrv" , DHCP_IP | 0x10, NULL, 0}, + {"routes" , DHCP_STCRTS | 0x21, NULL, 0}, + {"staticroutes" , DHCP_STCRTS | 0x79, NULL, 0}, + {"msstaticroutes" , DHCP_STCRTS | 0xf9, NULL, 0}, +}; + +struct fd_pair { int rd; int wr; }; +static server_config_t gconfig; +static server_state_t gstate; +static uint8_t infomode; +static struct fd_pair sigfd; +static int constone = 1; + +// calculate options size. +static int dhcp_opt_size(uint8_t *optionptr) +{ + int i = 0; + for(;optionptr[i] != 0xff; i++) if(optionptr[i] != 0x00) i += optionptr[i + 1] + 2 -1; + return i; +} + +// calculates checksum for dhcp messeges. +static uint16_t dhcp_checksum(void *addr, int count) +{ + int32_t sum = 0; + uint16_t tmp = 0, *source = (uint16_t *)addr; + + while (count > 1) { + sum += *source++; + count -= 2; + } + if (count > 0) { + *(uint8_t*)&tmp = *(uint8_t*)source; + sum += tmp; + } + while (sum >> 16) sum = (sum & 0xffff) + (sum >> 16); + return ~sum; +} + +// gets information of INTERFACE and updates IFINDEX, MAC and IP +static int get_interface(const char *interface, int *ifindex, uint32_t *oip, uint8_t *mac) +{ + struct ifreq req; + struct sockaddr_in *ip; + int fd = xsocket(AF_INET, SOCK_RAW, IPPROTO_RAW); + + req.ifr_addr.sa_family = AF_INET; + strncpy(req.ifr_name, interface, IFNAMSIZ); + req.ifr_name[IFNAMSIZ-1] = '\0'; + + xioctl(fd, SIOCGIFFLAGS, &req); + + if (!(req.ifr_flags & IFF_UP)) return -1; + if (oip) { + xioctl(fd, SIOCGIFADDR, &req); + ip = (struct sockaddr_in*) &req.ifr_addr; + dbg("IP %s\n", inet_ntoa(ip->sin_addr)); + *oip = ntohl(ip->sin_addr.s_addr); + } + if (ifindex) { + xioctl(fd, SIOCGIFINDEX, &req); + dbg("Adapter index %d\n", req.ifr_ifindex); + *ifindex = req.ifr_ifindex; + } + if (mac) { + xioctl(fd, SIOCGIFHWADDR, &req); + memcpy(mac, req.ifr_hwaddr.sa_data, 6); + dbg("MAC %02x:%02x:%02x:%02x:%02x:%02x\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); + } + close(fd); + return 0; +} + +/* + *logs messeges to syslog or console + *opening the log is still left with applet. + *FIXME: move to more relevent lib. probably libc.c + */ +static void infomsg(uint8_t infomode, char *s, ...) +{ + int used; + char *msg; + va_list p, t; + + if (infomode == LOG_SILENT) return; + va_start(p, s); + va_copy(t, p); + used = vsnprintf(NULL, 0, s, t); + used++; + va_end(t); + + msg = xmalloc(used); + vsnprintf(msg, used, s, p); + va_end(p); + + if (infomode & LOG_SYSTEM) syslog(LOG_INFO, "%s", msg); + if (infomode & LOG_CONSOLE) printf("%s\n", msg); + free(msg); +} + +/* + * Writes self PID in file PATH + * FIXME: libc implementation only writes in /var/run + * this is more generic as some implemenation may provide + * arguments to write in specific file. as dhcpd does. + */ +static void write_pid(char *path) +{ + int pidfile = open(path, O_CREAT | O_WRONLY | O_TRUNC, 0666); + if (pidfile > 0) { + char *pidbuf = utoa(getpid()); + write(pidfile, pidbuf, strlen(pidbuf)); + close(pidfile); + } +} + +// Generic signal handler real handling is done in main funcrion. +static void signal_handler(int sig) +{ + unsigned char ch = sig; + if (write(sigfd.wr, &ch, 1) != 1) dbg("can't send signal\n"); +} + +// signal setup for SIGUSR1 SIGTERM +static int setup_signal() +{ + if (pipe((int *)&sigfd) < 0) { + dbg("signal pipe failed\n"); + return -1; + } + fcntl(sigfd.wr , F_SETFD, FD_CLOEXEC); + fcntl(sigfd.rd , F_SETFD, FD_CLOEXEC); + int flags = fcntl(sigfd.wr, F_GETFL); + fcntl(sigfd.wr, F_SETFL, flags | O_NONBLOCK); + signal(SIGUSR1, signal_handler); + signal(SIGTERM, signal_handler); + return 0; +} + +// String STR to UINT32 conversion strored in VAR +static int strtou32(const char *str, void *var) +{ + char *endptr = NULL; + int base = 10; + errno=0; + *((uint32_t*)(var)) = 0; + if (str[0]=='0' && (str[1]=='x' || str[1]=='X')) { + base = 16; + str+=2; + } + long ret_val = strtol(str, &endptr, base); + if (errno) infomsg(infomode, "config : Invalid num %s",str); + else if (endptr && (*endptr!='\0'||endptr == str)) + infomsg(infomode, "config : Not a valid num %s",str); + else *((uint32_t*)(var)) = (uint32_t)ret_val; + return 0; +} + +// copy string STR in variable VAR +static int strinvar(const char *str, void *var) +{ + char **dest = var; + if (*dest) free(*dest); + *dest = strdup(str); + return 0; +} + +// IP String STR to binary data. +static int striptovar(const char *str, void *var) +{ + in_addr_t addr; + *((uint32_t*)(var)) = 0; + if(!str) { + error_msg("config : NULL address string \n"); + return -1; + } + if((addr = inet_addr(str)) == -1) { + error_msg("config : wrong address %s \n",str ); + return -1; + } + *((uint32_t*)(var)) = (uint32_t)addr; + return 0; +} + +// String to dhcp option conversion +static int strtoopt(const char *str, void *var) +{ + char *option, *valstr, *grp, *tp; + uint32_t optcode = 0, inf = infomode, convtmp, mask, nip, router; + uint16_t flag = 0; + int count, size = ARRAY_LEN(options_list); + + if (!*str) return 0; + if (!(option = strtok((char*)str, " \t="))) return -1; + + infomode = LOG_SILENT; + strtou32(option, (uint32_t*)&optcode); + infomode = inf; + + if (optcode > 0 && optcode < 256) { // raw option + for (count = 0; count < size; count++) { + if ((options_list[count].code & 0X00FF) == optcode) { + flag = (options_list[count].code & 0XFF00); + break; + } + } + } else { //string option + for (count = 0; count < size; count++) { + if (!strncmp(options_list[count].key, option, strlen(options_list[count].key))) { + flag = (options_list[count].code & 0XFF00); + optcode = (options_list[count].code & 0X00FF); + break; + } + } + } + if (count == size) { + infomsg(inf, "config : Obsolete OR Unknown Option : %s", option); + return -1; + } + + if (!flag || !optcode) return -1; + + if (!(valstr = strtok(NULL, " \t"))) { + dbg("config : option %s has no value defined.\n", option); + return -1; + } + dbg(" value : %-20s : ", valstr); + switch (flag) { + case DHCP_NUM32: + options_list[count].len = sizeof(uint32_t); + options_list[count].val = xmalloc(sizeof(uint32_t)); + strtou32(valstr, &convtmp); + memcpy(options_list[count].val, &convtmp, sizeof(uint32_t)); + break; + case DHCP_NUM16: + options_list[count].len = sizeof(uint16_t); + options_list[count].val = xmalloc(sizeof(uint16_t)); + strtou32(valstr, &convtmp); + memcpy(options_list[count].val, &convtmp, sizeof(uint16_t)); + break; + case DHCP_NUM8: + options_list[count].len = sizeof(uint8_t); + options_list[count].val = xmalloc(sizeof(uint8_t)); + strtou32(valstr, &convtmp); + memcpy(options_list[count].val, &convtmp, sizeof(uint8_t)); + break; + case DHCP_IP: + options_list[count].len = sizeof(uint32_t); + options_list[count].val = xmalloc(sizeof(uint32_t)); + striptovar(valstr, options_list[count].val); + break; + case DHCP_STRING: + options_list[count].len = strlen(valstr); + options_list[count].val = strdup(valstr); + break; + case DHCP_IPLIST: + while(valstr){ + options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + sizeof(uint32_t)); + striptovar(valstr, ((uint8_t*)options_list[count].val)+options_list[count].len); + options_list[count].len += sizeof(uint32_t); + valstr = strtok(NULL," \t"); + } + break; + case DHCP_IPPLST: + break; + case DHCP_STCRTS: + /* Option binary format: + * mask [one byte, 0..32] + * ip [0..4 bytes depending on mask] + * router [4 bytes] + * may be repeated + * staticroutes 10.0.0.0/8 10.127.0.1, 10.11.12.0/24 10.11.12.1 + */ + grp = strtok(valstr, ",");; + while(grp){ + while(*grp == ' ' || *grp == '\t') grp++; + tp = strchr(grp, '/'); + if (!tp) error_exit("wrong formated static route option"); + *tp = '\0'; + mask = strtol(++tp, &tp, 10); + if (striptovar(grp, (uint8_t*)&nip)<0) error_exit("wrong formated static route option"); + while(*tp == ' ' || *tp == '\t' || *tp == '-') tp++; + if (striptovar(tp, (uint8_t*)&router)<0) error_exit("wrong formated static route option"); + options_list[count].val = xrealloc(options_list[count].val, options_list[count].len + 1 + mask/8 + 4); + memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &mask, 1); + options_list[count].len += 1; + memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &nip, mask/8); + options_list[count].len += mask/8; + memcpy(((uint8_t*)options_list[count].val)+options_list[count].len, &router, 4); + options_list[count].len += 4; + tp = NULL; + grp = strtok(NULL, ","); + } + break; + } + return 0; +} + +// Reads Static leases from STR and updates inner structures. +static int get_staticlease(const char *str, void *var) +{ + struct static_lease_s *sltmp; + char *tkmac, *tkip; + int count; + + if (!*str) return 0; + + if (!(tkmac = strtok((char*)str, " \t"))) { + infomsg(infomode, "config : static lease : mac not found"); + return 0; + } + if (!(tkip = strtok(NULL, " \t"))) { + infomsg(infomode, "config : static lease : no ip bind to mac %s", tkmac); + return 0; + } + sltmp = xzalloc(sizeof(struct static_lease_s)); + for (count = 0; count < 6; count++, tkmac++) { + errno = 0; + sltmp->mac[count] = strtol(tkmac, &tkmac, 16); + if (sltmp->mac[count]>255 || sltmp->mac[count]<0 || (*tkmac && *tkmac!=':') || errno) { + infomsg(infomode, "config : static lease : mac address wrong format"); + free(sltmp); + return 0; + } + } + striptovar(tkip, &sltmp->nip); + sltmp->next = gstate.sleases; + gstate.sleases = sltmp; + + return 0; +} + +static struct config_keyword keywords[] = { +// keyword handler variable address default + {"start" , striptovar , (void*)&gconfig.start_ip , "192.168.0.20"}, + {"end" , striptovar , (void*)&gconfig.end_ip , "192.168.0.254"}, + {"interface" , strinvar , (void*)&gconfig.interface , "eth0"}, + {"port" , strtou32 , (void*)&gconfig.port , "67"}, + {"min_lease" , strtou32 , (void*)&gconfig.min_lease_sec, "60"}, + {"max_leases" , strtou32 , (void*)&gconfig.max_leases , "235"}, + {"auto_time" , strtou32 , (void*)&gconfig.auto_time , "7200"}, + {"decline_time" , strtou32 , (void*)&gconfig.decline_time , "3600"}, + {"conflict_time", strtou32 , (void*)&gconfig.conflict_time, "3600"}, + {"offer_time" , strtou32 , (void*)&gconfig.offer_time , "60"}, + {"lease_file" , strinvar , (void*)&gconfig.lease_file , "/var/lib/misc/dhcpd.leases"}, //LEASES_FILE + {"pidfile" , strinvar , (void*)&gconfig.pidfile , "/var/run/dhcpd.pid"}, //DPID_FILE + {"siaddr" , striptovar , (void*)&gconfig.siaddr_nip , "0.0.0.0"}, + {"option" , strtoopt , (void*)&gconfig.options , ""}, + {"opt" , strtoopt , (void*)&gconfig.options , ""}, + {"notify_file" , strinvar , (void*)&gconfig.notify_file , ""}, + {"sname" , strinvar , (void*)&gconfig.sname , ""}, + {"boot_file" , strinvar , (void*)&gconfig.boot_file , ""}, + {"static_lease" , get_staticlease , (void*)&gconfig.static_leases, ""}, +}; + +// Parses the server config file and updates the global server config accordingly. +static int parse_server_config(char *config_file, struct config_keyword *confkey) +{ + FILE *fs = NULL; + char *confline_temp = NULL,*confline = NULL, *tk = NULL, *tokens[2] = {NULL, NULL}; + int len, linelen, tcount, count, size = ARRAY_LEN(keywords); + + for (count = 0; count < size; count++) + if (confkey[count].handler) confkey[count].handler(confkey[count].def, confkey[count].var); + + if (!(fs = fopen(config_file, "r"))) perror_msg("%s", config_file); + for (len = 0, linelen = 0; fs;) { + len = getline(&confline_temp, (size_t*) &linelen, fs); + confline = confline_temp; + if (len <= 0) break; + for (; *confline == ' '; confline++, len--); + if ((confline[0] == '#') || (confline[0] == '\n')) goto free_conf_continue; + tk = strchr(confline, '#'); + if (tk) { + for (; *(tk-1)==' ' || *(tk-1)=='\t'; tk--); + *tk = '\0'; + } + tk = strchr(confline, '\n'); + if (tk) { + for (; *(tk-1)==' ' || *(tk-1)=='\t'; tk--); + *tk = '\0'; + } + for (tcount=0, tk=strtok(confline, " \t"); tk && (tcount < 2); + tcount++, tk=strtok(NULL,(tcount==1)?"":" \t")) { + while ((*tk == '\t') || (*tk == ' ')) tk++; + tokens[tcount] = xstrdup(tk); + } + if (tcount<=1) goto free_tk0_continue; + for (count = 0; count < size; count++) { + if (!strcmp(confkey[count].keyword,tokens[0])) { + dbg("got config : %15s : ", confkey[count].keyword); + if (confkey[count].handler(tokens[1], confkey[count].var) == 0) + dbg("%s \n", tokens[1]); + break; + } + } + if (tokens[1]) { free(tokens[1]); tokens[1] = NULL; } +free_tk0_continue: + if (tokens[0]) { free(tokens[0]); tokens[0] = NULL; } +free_conf_continue: + free(confline_temp); + confline_temp = NULL; + } + if (fs) fclose(fs); + return 0; +} + +// opens UDP socket for listen +static int open_listensock(void) +{ + struct sockaddr_in addr; + struct ifreq ifr; + + if (gstate.listensock > 0) close(gstate.listensock); + + dbg("Opening listen socket on *:%d %s\n", gconfig.port, gconfig.interface); + gstate.listensock = xsocket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); + setsockopt(gstate.listensock, SOL_SOCKET, SO_REUSEADDR, &constone, sizeof(constone)); + if (setsockopt(gstate.listensock, SOL_SOCKET, SO_BROADCAST, &constone, sizeof(constone)) == -1) { + dbg("OPEN : brodcast ioctl failed.\n"); + close(gstate.listensock); + return -1; + } + memset(&ifr, 0, sizeof(ifr)); + strncpy(ifr.ifr_name, gconfig.interface, IFNAMSIZ); + ifr.ifr_name[IFNAMSIZ -1] = '\0'; + setsockopt(gstate.listensock, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)); + + memset(&addr, 0, sizeof(addr)); + addr.sin_family = AF_INET; + addr.sin_port = (flag_chk(FLAG_P))?htons(TT.port):htons(67); //SERVER_PORT + addr.sin_addr.s_addr = INADDR_ANY ; + + if (bind(gstate.listensock, (struct sockaddr *) &addr, sizeof(addr))) { + close(gstate.listensock); + perror_exit("bind failed"); + } + dbg("OPEN : success\n"); + return 0; +} + +// Sends data through raw socket. +static int send_packet(uint8_t broadcast) +{ + struct sockaddr_ll dest_sll; + dhcp_raw_t packet; + unsigned padding; + int fd, result = -1; + uint8_t bmacaddr[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; + + memset(&packet, 0, sizeof(dhcp_raw_t)); + memcpy(&packet.dhcp, &gstate.send_pkt, sizeof(dhcp_msg_t)); + + if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) { + dbg("SEND : socket failed\n"); + return -1; + } + memset(&dest_sll, 0, sizeof(dest_sll)); + dest_sll.sll_family = AF_PACKET; + dest_sll.sll_protocol = htons(ETH_P_IP); + dest_sll.sll_ifindex = gconfig.ifindex; + dest_sll.sll_halen = 6; + memcpy(dest_sll.sll_addr, (broadcast)?bmacaddr:gstate.rcvd_pkt.chaddr , 6); + + if (bind(fd, (struct sockaddr *) &dest_sll, sizeof(dest_sll)) < 0) { + dbg("SEND : bind failed\n"); + close(fd); + return -1; + } + padding = 308 - 1 - dhcp_opt_size(gstate.send_pkt.options); + packet.iph.protocol = IPPROTO_UDP; + packet.iph.saddr = gconfig.server_nip; + packet.iph.daddr = (broadcast || (gstate.rcvd_pkt.ciaddr == 0))?INADDR_BROADCAST:gstate.rcvd_pkt.ciaddr; + packet.udph.source = htons(67);//SERVER_PORT + packet.udph.dest = htons(68); //CLIENT_PORT + packet.udph.len = htons(sizeof(dhcp_raw_t) - sizeof(struct iphdr) - padding); + packet.iph.tot_len = packet.udph.len; + packet.udph.check = dhcp_checksum(&packet, sizeof(dhcp_raw_t) - padding); + packet.iph.tot_len = htons(sizeof(dhcp_raw_t) - padding); + packet.iph.ihl = sizeof(packet.iph) >> 2; + packet.iph.version = IPVERSION; + packet.iph.ttl = IPDEFTTL; + packet.iph.check = dhcp_checksum(&packet.iph, sizeof(packet.iph)); + + result = sendto(fd, &packet, sizeof(dhcp_raw_t) - padding, 0, + (struct sockaddr *) &dest_sll, sizeof(dest_sll)); + + dbg("sendto %d\n", result); + close(fd); + if (result < 0) dbg("PACKET send error\n"); + return result; +} + +// Reads from UDP socket +static int read_packet(void) +{ + int ret; + + memset(&gstate.rcvd_pkt, 0, sizeof(dhcp_msg_t)); + ret = read(gstate.listensock, &gstate.rcvd_pkt, sizeof(dhcp_msg_t)); + if (ret < 0) { + dbg("Packet read error, ignoring. \n"); + return ret; // returns -1 + } + if (gstate.rcvd_pkt.cookie != htonl(DHCP_MAGIC)) { + dbg("Packet with bad magic, ignoring. \n"); + return -2; + } + if (gstate.rcvd_pkt.op != 1) { //BOOTPREQUEST + dbg("Not a BOOT REQUEST ignoring. \n"); + return -2; + } + if (gstate.rcvd_pkt.hlen != 6) { + dbg("hlen != 6 ignoring. \n"); + return -2; + } + dbg("Received a packet. Size : %d \n", ret); + return ret; +} + +// Preapres a dhcp packet with defaults and configs +static uint8_t* prepare_send_pkt(void) +{ + memset((void*)&gstate.send_pkt, 0, sizeof(gstate.send_pkt)); + gstate.send_pkt.op = 2; //BOOTPREPLY + gstate.send_pkt.htype = 1; + gstate.send_pkt.hlen = 6; + gstate.send_pkt.xid = gstate.rcvd_pkt.xid; + gstate.send_pkt.cookie = htonl(DHCP_MAGIC); + gstate.send_pkt.nsiaddr = gconfig.server_nip; + memcpy(gstate.send_pkt.chaddr, gstate.rcvd_pkt.chaddr, 16); + gstate.send_pkt.options[0] = DHCP_OPT_END; + return gstate.send_pkt.options; +} + +// Sets a option value in dhcp packet's option field +static uint8_t* set_optval(uint8_t *optptr, uint16_t opt, void *var, size_t len) +{ + while (*optptr != DHCP_OPT_END) optptr++; + *optptr++ = (uint8_t)(opt & 0x00FF); + *optptr++ = (uint8_t) len; + memcpy(optptr, var, len); + optptr += len; + *optptr = DHCP_OPT_END; + return optptr; +} + +// Gets a option value from dhcp packet's option field +static uint8_t* get_optval(uint8_t *optptr, uint16_t opt, void *var) +{ + size_t len; + uint8_t overloaded = 0; + + while (1) { + while (*optptr == DHCP_OPT_PADDING) optptr++; + if ((*optptr & 0x00FF) == DHCP_OPT_END) break; + if ((*optptr & 0x00FF) == DHCP_OPT_OPTION_OVERLOAD) { + overloaded = optptr[2]; + optptr += optptr[1] + 2; + } + len = optptr[1]; + if (*optptr == (opt & 0x00FF)) + switch (opt & 0xFF00) { + case DHCP_NUM32: // FALLTHROUGH + case DHCP_IP: + memcpy(var, optptr+2, sizeof(uint32_t)); + optptr += len + 2; + return optptr; + break; + case DHCP_NUM16: + memcpy(var, optptr+2, sizeof(uint16_t)); + optptr += len + 2; + return optptr; + break; + case DHCP_NUM8: + memcpy(var, optptr+2, sizeof(uint8_t)); + optptr += len + 2; + return optptr; + break; + case DHCP_STRING: + var = xstrndup((char*) optptr, len); + optptr += len + 2; + return optptr; + break; + } + optptr += len + 2; + } + if ((overloaded == 1) | (overloaded == 3)) get_optval((uint8_t*)&gstate.rcvd_pkt.file, opt, var); + if ((overloaded == 2) | (overloaded == 3)) get_optval((uint8_t*)&gstate.rcvd_pkt.sname, opt, var); + return optptr; +} + +// Retrives Requested Parameter list from dhcp req packet. +static uint8_t get_reqparam(uint8_t **list) +{ + uint8_t len, *optptr; + if(*list) free(*list); + for (optptr = gstate.rcvd_pkt.options; + *optptr && *optptr!=((DHCP_OPT_PARAM_REQ) & 0x00FF); optptr+=optptr[1]+2); + len = *++optptr; + *list = xzalloc(len+1); + memcpy(*list, ++optptr, len); + return len; +} + +// Sets values of req param in dhcp offer packet. +static uint8_t* set_reqparam(uint8_t *optptr, uint8_t *list) +{ + uint8_t reqcode; + int count, size = ARRAY_LEN(options_list); + + while (*list) { + reqcode = *list++; + for (count = 0; count < size; count++) { + if ((options_list[count].code & 0X00FF)==reqcode) { + if (!(options_list[count].len) || !(options_list[count].val)) break; + for (; *optptr && *optptr!=DHCP_OPT_END; optptr+=optptr[1]+2); + *optptr++ = (uint8_t) (options_list[count].code & 0x00FF); + *optptr++ = (uint8_t) options_list[count].len; + memcpy(optptr, options_list[count].val, options_list[count].len); + optptr += options_list[count].len; + *optptr = DHCP_OPT_END; + break; + } + } + } + return optptr; +} + +static void run_notify(char **argv) +{ + struct stat sts; + volatile int error = 0; + pid_t pid; + + if (stat(argv[0], &sts) == -1 && errno == ENOENT) { + infomsg(infomode, "notify file: %s : not exist.", argv[0]); + return; + } + fflush(NULL); + + pid = vfork(); + if (pid < 0) { + dbg("Fork failed.\n"); + return; + } + if (!pid) { + execvp(argv[0], argv); + error = errno; + _exit(111); + } + if (error) { + waitpid(pid, NULL, 0); + errno = error; + } + dbg("script complete.\n"); +} + +static int write_leasefile(void) +{ + int fd; + uint32_t curr, tmp_time; + int64_t timestamp; + struct arg_list *listdls = gstate.dleases; + dyn_lease *dls; + + if ((fd = open(gconfig.lease_file, O_WRONLY | O_CREAT | O_TRUNC)) < 0) { + perror_msg("can't open %s ", gconfig.lease_file); + return fd; + } + + curr = timestamp = time(NULL); + timestamp = SWAP_BE64(timestamp); + writeall(fd, ×tamp, sizeof(timestamp)); + + while (listdls) { + dls = (dyn_lease*)listdls->arg; + tmp_time = dls->expires; + dls->expires -= curr; + if ((int32_t) dls->expires < 0) goto skip; + dls->expires = htonl(dls->expires); + writeall(fd, dls, sizeof(dyn_lease)); +skip: + dls->expires = tmp_time; + listdls = listdls->next; + } + close(fd); + if (gconfig.notify_file) { + char *argv[3]; + argv[0] = gconfig.notify_file; + argv[1] = gconfig.lease_file; + argv[2] = NULL; + run_notify(argv); + } + return 0; +} + +// Update max lease time from options. +static void set_maxlease(void) +{ + int count, size = ARRAY_LEN(options_list); + for (count = 0; count < size; count++) + if (options_list[count].val && options_list[count].code == (DHCP_OPT_LEASE_TIME)) { + gconfig.max_lease_sec = *((uint32_t*)options_list[count].val); + break; + } + if (!gconfig.max_lease_sec) gconfig.max_lease_sec = (60*60*24*10);// DEFAULT_LEASE_TIME; +} + +// Returns lease time for client. +static uint32_t get_lease(uint32_t req_exp) +{ + uint32_t now = time(NULL); + req_exp = req_exp - now; + if ((req_exp <= 0) || (req_exp > gconfig.max_lease_sec)) + return gconfig.max_lease_sec; + + if (req_exp < gconfig.min_lease_sec) + return gconfig.min_lease_sec; + + return req_exp; +} + +// Verify ip NIP in current leases ( assigned or not) +static int verifyip_in_lease(uint32_t nip, uint8_t mac[6]) +{ + static_lease *sls; + struct arg_list *listdls; + + for (listdls = gstate.dleases; listdls; listdls = listdls->next) { + if (((dyn_lease*) listdls->arg)->lease_nip == nip) { + if (((int32_t)(((dyn_lease*) listdls->arg)->expires) - time(NULL)) < 0) + return 0; + return -1; + } + if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) return -1; + } + for (sls = gstate.sleases; sls; sls = sls->next) + if (sls->nip == nip) return -2; + + if ((ntohl(nip) < gconfig.start_ip) || (ntohl(nip) > gconfig.end_ip)) + return -3; + + return 0; +} + +// add ip assigned_nip to dynamic lease. +static int addip_to_lease(uint32_t assigned_nip, uint8_t mac[6], uint32_t *req_exp, char *hostname, uint8_t update) +{ + dyn_lease *dls; + struct arg_list *listdls = gstate.dleases; + uint32_t now = time(NULL); + + while (listdls) { + if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) { + if (update) *req_exp = get_lease(*req_exp + ((dyn_lease*) listdls->arg)->expires); + ((dyn_lease*) listdls->arg)->expires = *req_exp + now; + return 0; + } + listdls = listdls->next; + } + + dls = xzalloc(sizeof(dyn_lease)); + memcpy(dls->lease_mac, mac, 6); + dls->lease_nip = assigned_nip; + if (hostname) memcpy(dls->hostname, hostname, 20); + + if (update) *req_exp = get_lease(*req_exp + now); + dls->expires = *req_exp + now; + + listdls = xzalloc(sizeof(struct arg_list)); + listdls->next = gstate.dleases; + listdls->arg = (char*)dls; + gstate.dleases = listdls; + + return 0; +} + +// delete ip assigned_nip from dynamic lease. +static int delip_from_lease(uint32_t assigned_nip, uint8_t mac[6], uint32_t del_time) +{ + struct arg_list *listdls = gstate.dleases; + + while (listdls) { + if (!memcmp(((dyn_lease*) listdls->arg)->lease_mac, mac, 6)) { + ((dyn_lease*) listdls->arg)->expires = del_time + time(NULL); + return 0; + } + listdls = listdls->next; + } + return -1; +} + +// returns a IP from static, dynamic leases or free ip pool, 0 otherwise. +static uint32_t getip_from_pool(uint32_t req_nip, uint8_t mac[6], uint32_t *req_exp, char *hostname) +{ + uint32_t nip = 0; + static_lease *sls = gstate.sleases; + struct arg_list *listdls = gstate.dleases, *tmp = NULL; + + if (req_nip && (!verifyip_in_lease(req_nip, mac))) nip = req_nip; + + if (!nip) { + while (listdls) { + if (!memcmp(((dyn_lease*)listdls->arg)->lease_mac, mac, 6)) { + nip = ((dyn_lease*)listdls->arg)->lease_nip; + if (tmp) tmp->next = listdls->next; + else gstate.dleases = listdls->next; + free(listdls->arg); + free(listdls); + if (verifyip_in_lease(nip, mac) < 0) nip = 0; + break; + } + tmp = listdls; + listdls = listdls->next; + } + } + if (!nip) { + while (sls) { + if (memcmp(sls->mac, mac, 6) == 0) { + nip = sls->nip; + break; + } + sls = sls->next; + } + } + if (!nip) { + for (nip = htonl(gconfig.start_ip); ntohl(nip) <= gconfig.end_ip; ) { + if (!verifyip_in_lease(nip, mac)) break; + nip = ntohl(nip); + nip = htonl(++nip); + } + if (ntohl(nip) > gconfig.end_ip) { + nip = 0; + infomsg(infomode, "can't find free IP in IP Pool."); + } + } + if (nip) addip_to_lease(nip, mac, req_exp, hostname, 1); + return nip; +} + +static int read_leasefile(void) +{ + uint32_t passed, ip; + int32_t tmp_time; + int64_t timestamp; + dyn_lease *dls; + int ret = -1, fd = open(gconfig.lease_file, O_RDONLY); + + if (fd < 0) return fd; + dls = xzalloc(sizeof(dyn_lease)); + + if (read(fd, ×tamp, sizeof(timestamp)) != sizeof(timestamp)) goto error_exit; + + timestamp = SWAP_BE64(timestamp); + passed = time(NULL) - timestamp; + if ((uint64_t)passed > 12 * 60 * 60) goto error_exit; + + while (read(fd, dls, sizeof(dyn_lease)) == sizeof(dyn_lease)) { + ip = ntohl(dls->lease_nip); + if (ip >= gconfig.start_ip && ip <= gconfig.end_ip) { + tmp_time = ntohl(dls->expires) - passed; + if (tmp_time < 0) continue; + addip_to_lease(dls->lease_nip, dls->lease_mac, (uint32_t*)&tmp_time, dls->hostname, 0); + } + } + ret = 0; +error_exit: + free(dls); + close(fd); + return ret; +} + +void dhcpd_main(void) +{ + struct timeval tv; + int retval; + uint8_t *optptr, msgtype = 0; + uint32_t waited = 0, serverid = 0, requested_nip = 0; + uint32_t reqested_lease = 0, ip_pool_size = 0; + char *hstname = NULL; + fd_set rfds; + + infomode = LOG_CONSOLE; + if (!(flag_chk(FLAG_f))) { + daemonize(); + infomode = LOG_SILENT; + } + if (flag_chk(FLAG_S)) { + openlog("UDHCPD :", LOG_PID, LOG_DAEMON); + infomode |= LOG_SYSTEM; + } + setlinebuf(stdout); + parse_server_config((toys.optc==1)?toys.optargs[0]:"/etc/dhcpd.conf", keywords); //DHCPD_CONF_FILE + infomsg(infomode, "toybox dhcpd started"); + gconfig.start_ip = ntohl(gconfig.start_ip); + gconfig.end_ip = ntohl(gconfig.end_ip); + ip_pool_size = gconfig.end_ip - gconfig.start_ip + 1; + if (gconfig.max_leases > ip_pool_size) { + error_msg("max_leases=%u is too big, setting to %u", (unsigned) gconfig.max_leases, ip_pool_size); + gconfig.max_leases = ip_pool_size; + } + write_pid(gconfig.pidfile); + set_maxlease(); + read_leasefile(); + + if (get_interface(gconfig.interface, &gconfig.ifindex, &gconfig.server_nip, + gconfig.server_mac)<0) + perror_exit("Failed to get interface %s", gconfig.interface); + gconfig.server_nip = htonl(gconfig.server_nip); + + setup_signal(); + open_listensock(); + fcntl(gstate.listensock, F_SETFD, FD_CLOEXEC); + + for (;;) { + uint32_t timestmp = time(NULL); + FD_ZERO(&rfds); + FD_SET(gstate.listensock, &rfds); + FD_SET(sigfd.rd, &rfds); + tv.tv_sec = gconfig.auto_time - waited; + tv.tv_usec = 0; + retval = 0; + serverid = 0; + msgtype = 0; + + int maxfd = (sigfd.rd > gstate.listensock)? sigfd.rd : gstate.listensock; + dbg("select waiting ....\n"); + retval = select(maxfd + 1, &rfds, NULL, NULL, (gconfig.auto_time?&tv:NULL)); + if (retval < 0) { + if (errno == EINTR) { + waited += (unsigned) time(NULL) - timestmp; + continue; + } + dbg("Error in select wait again...\n"); + continue; + } + if (!retval) { // Timed out + dbg("select wait Timed Out...\n"); + waited = 0; + write_leasefile(); + if (get_interface(gconfig.interface, &gconfig.ifindex, &gconfig.server_nip, gconfig.server_mac)<0) + perror_exit("Interface lost %s\n", gconfig.interface); + gconfig.server_nip = htonl(gconfig.server_nip); + continue; + } + if (FD_ISSET(sigfd.rd, &rfds)) { // Some Activity on RDFDs : is signal + unsigned char sig; + if (read(sigfd.rd, &sig, 1) != 1) { + dbg("signal read failed.\n"); + continue; + } + switch (sig) { + case SIGUSR1: + infomsg(infomode, "Received SIGUSR1"); + write_leasefile(); + continue; + case SIGTERM: + infomsg(infomode, "Received SIGTERM"); + write_leasefile(); + unlink(gconfig.pidfile); + exit(0); + break; + default: break; + } + } + if (FD_ISSET(gstate.listensock, &rfds)) { // Some Activity on RDFDs : is socket + dbg("select listen sock read\n"); + if (read_packet() < 0) { + open_listensock(); + continue; + } + waited += time(NULL) - timestmp; + get_optval((uint8_t*)&gstate.rcvd_pkt.options, DHCP_OPT_MESSAGE_TYPE, &gstate.rqcode); + if (gstate.rqcode == 0 || gstate.rqcode < DHCPDISCOVER + || gstate.rqcode > DHCPINFORM) { + dbg("no or bad message type option, ignoring packet.\n"); + continue; + } + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_SERVER_ID, &serverid); + if (serverid && (serverid != gconfig.server_nip)) { + dbg("server ID doesn't match, ignoring packet.\n"); + continue; + } + switch (gstate.rqcode) { + case DHCPDISCOVER: + msgtype = DHCPOFFER; + dbg("Message Type : DHCPDISCOVER\n"); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_HOST_NAME, &hstname); + reqested_lease = gconfig.offer_time; + get_reqparam(&gstate.rqopt); + optptr = prepare_send_pkt(); + gstate.send_pkt.yiaddr = getip_from_pool(requested_nip, gstate.rcvd_pkt.chaddr, &reqested_lease, hstname); + if(!gstate.send_pkt.yiaddr){ + msgtype = DHCPNAK; + optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1); + send_packet(1); + break; + } + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_LEASE_TIME, &reqested_lease); + reqested_lease = htonl(get_lease(reqested_lease + time(NULL))); + optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1); + optptr = set_optval(optptr, DHCP_OPT_SERVER_ID, &gconfig.server_nip, 4); + optptr = set_optval(optptr, DHCP_OPT_LEASE_TIME, &reqested_lease, 4); + optptr = set_reqparam(optptr, gstate.rqopt); + send_packet(1); + break; + case DHCPREQUEST: + msgtype = DHCPACK; + dbg("Message Type : DHCPREQUEST\n"); + optptr = prepare_send_pkt(); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_LEASE_TIME, &reqested_lease); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_HOST_NAME, &hstname); + gstate.send_pkt.yiaddr = getip_from_pool(requested_nip, gstate.rcvd_pkt.chaddr, &reqested_lease, hstname); + if (!serverid) reqested_lease = gconfig.max_lease_sec; + if (!gstate.send_pkt.yiaddr) { + msgtype = DHCPNAK; + optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1); + send_packet(1); + break; + } + optptr = set_optval(optptr, DHCP_OPT_MESSAGE_TYPE, &msgtype, 1); + optptr = set_optval(optptr, DHCP_OPT_SERVER_ID, &gconfig.server_nip, 4); + reqested_lease = htonl(reqested_lease); + optptr = set_optval(optptr, DHCP_OPT_LEASE_TIME, &reqested_lease, 4); + send_packet(1); + write_leasefile(); + break; + case DHCPDECLINE:// FALL THROUGH + case DHCPRELEASE: + dbg("Message Type : DHCPDECLINE or DHCPRELEASE \n"); + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_SERVER_ID, &serverid); + if (serverid != gconfig.server_nip) break; + get_optval((uint8_t*) &gstate.rcvd_pkt.options, DHCP_OPT_REQUESTED_IP, &requested_nip); + delip_from_lease(requested_nip, gstate.rcvd_pkt.chaddr, (gstate.rqcode==DHCPRELEASE)?0:gconfig.decline_time); + break; + default: + dbg("Message Type : %u\n", gstate.rqcode); + break; + } + } + } +} -- cgit v1.2.3