1 files changed, 221 insertions, 2 deletions

diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index e93a9f1da..8bd65df52 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -33,11 +33,232 @@
 //usage:     "\n        -P N    Use port N (default 67)"
 //usage:        )
 
+#include <netinet/ether.h>
 #include <syslog.h>
 #include "common.h"
 #include "dhcpc.h"
 #include "dhcpd.h"
 
+/* on these functions, make sure your datatype matches */
+static int FAST_FUNC read_str(const char *line, void *arg)
+{
+        char **dest = arg;
+
+        free(*dest);
+        *dest = xstrdup(line);
+        return 1;
+}
+
+static int FAST_FUNC read_u32(const char *line, void *arg)
+{
+        *(uint32_t*)arg = bb_strtou32(line, NULL, 10);
+        return errno == 0;
+}
+
+static int FAST_FUNC read_staticlease(const char *const_line, void *arg)
+{
+        char *line;
+        char *mac_string;
+        char *ip_string;
+        struct ether_addr mac_bytes; /* it's "struct { uint8_t mac[6]; }" */
+        uint32_t nip;
+
+        /* Read mac */
+        line = (char *) const_line;
+        mac_string = strtok_r(line, " \t", &line);
+        if (!mac_string || !ether_aton_r(mac_string, &mac_bytes))
+                return 0;
+
+        /* Read ip */
+        ip_string = strtok_r(NULL, " \t", &line);
+        if (!ip_string || !udhcp_str2nip(ip_string, &nip))
+                return 0;
+
+        add_static_lease(arg, (uint8_t*) &mac_bytes, nip);
+
+        log_static_leases(arg);
+
+        return 1;
+}
+
+struct config_keyword {
+        const char *keyword;
+        int (*handler)(const char *line, void *var) FAST_FUNC;
+        unsigned ofs;
+        const char *def;
+};
+
+#define OFS(field) offsetof(struct server_config_t, field)
+
+static const struct config_keyword keywords[] = {
+        /* keyword        handler           variable address               default */
+        {"start"        , udhcp_str2nip   , OFS(start_ip     ), "192.168.0.20"},
+        {"end"          , udhcp_str2nip   , OFS(end_ip       ), "192.168.0.254"},
+        {"interface"    , read_str        , OFS(interface    ), "eth0"},
+        /* Avoid "max_leases value not sane" warning by setting default
+         * to default_end_ip - default_start_ip + 1: */
+        {"max_leases"   , read_u32        , OFS(max_leases   ), "235"},
+        {"auto_time"    , read_u32        , OFS(auto_time    ), "7200"},
+        {"decline_time" , read_u32        , OFS(decline_time ), "3600"},
+        {"conflict_time", read_u32        , OFS(conflict_time), "3600"},
+        {"offer_time"   , read_u32        , OFS(offer_time   ), "60"},
+        {"min_lease"    , read_u32        , OFS(min_lease_sec), "60"},
+        {"lease_file"   , read_str        , OFS(lease_file   ), LEASES_FILE},
+        {"pidfile"      , read_str        , OFS(pidfile      ), "/var/run/udhcpd.pid"},
+        {"siaddr"       , udhcp_str2nip   , OFS(siaddr_nip   ), "0.0.0.0"},
+        /* keywords with no defaults must be last! */
+        {"option"       , udhcp_str2optset, OFS(options      ), ""},
+        {"opt"          , udhcp_str2optset, OFS(options      ), ""},
+        {"notify_file"  , read_str        , OFS(notify_file  ), NULL},
+        {"sname"        , read_str        , OFS(sname        ), NULL},
+        {"boot_file"    , read_str        , OFS(boot_file    ), NULL},
+        {"static_lease" , read_staticlease, OFS(static_leases), ""},
+};
+enum { KWS_WITH_DEFAULTS = ARRAY_SIZE(keywords) - 6 };
+
+static NOINLINE void read_config(const char *file)
+{
+        parser_t *parser;
+        const struct config_keyword *k;
+        unsigned i;
+        char *token[2];
+
+        for (i = 0; i < KWS_WITH_DEFAULTS; i++)
+                keywords[i].handler(keywords[i].def, (char*)&server_config + keywords[i].ofs);
+
+        parser = config_open(file);
+        while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL)) {
+                for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
+                        if (strcasecmp(token[0], k->keyword) == 0) {
+                                if (!k->handler(token[1], (char*)&server_config + k->ofs)) {
+                                        bb_error_msg("can't parse line %u in %s",
+                                                        parser->lineno, file);
+                                        /* reset back to the default value */
+                                        k->handler(k->def, (char*)&server_config + k->ofs);
+                                }
+                                break;
+                        }
+                }
+        }
+        config_close(parser);
+
+        server_config.start_ip = ntohl(server_config.start_ip);
+        server_config.end_ip = ntohl(server_config.end_ip);
+}
+
+static void write_leases(void)
+{
+        int fd;
+        unsigned i;
+        leasetime_t curr;
+        int64_t written_at;
+
+        fd = open_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC);
+        if (fd < 0)
+                return;
+
+        curr = written_at = time(NULL);
+
+        written_at = SWAP_BE64(written_at);
+        full_write(fd, &written_at, sizeof(written_at));
+
+        for (i = 0; i < server_config.max_leases; i++) {
+                leasetime_t tmp_time;
+
+                if (g_leases[i].lease_nip == 0)
+                        continue;
+
+                /* Screw with the time in the struct, for easier writing */
+                tmp_time = g_leases[i].expires;
+
+                g_leases[i].expires -= curr;
+                if ((signed_leasetime_t) g_leases[i].expires < 0)
+                        g_leases[i].expires = 0;
+                g_leases[i].expires = htonl(g_leases[i].expires);
+
+                /* No error check. If the file gets truncated,
+                 * we lose some leases on restart. Oh well. */
+                full_write(fd, &g_leases[i], sizeof(g_leases[i]));
+
+                /* Then restore it when done */
+                g_leases[i].expires = tmp_time;
+        }
+        close(fd);
+
+        if (server_config.notify_file) {
+                char *argv[3];
+                argv[0] = server_config.notify_file;
+                argv[1] = server_config.lease_file;
+                argv[2] = NULL;
+                spawn_and_wait(argv);
+        }
+}
+
+static NOINLINE void read_leases(const char *file)
+{
+        struct dyn_lease lease;
+        int64_t written_at, time_passed;
+        int fd;
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+        unsigned i = 0;
+#endif
+
+        fd = open_or_warn(file, O_RDONLY);
+        if (fd < 0)
+                return;
+
+        if (full_read(fd, &written_at, sizeof(written_at)) != sizeof(written_at))
+                goto ret;
+        written_at = SWAP_BE64(written_at);
+
+        time_passed = time(NULL) - written_at;
+        /* Strange written_at, or lease file from old version of udhcpd
+         * which had no "written_at" field? */
+        if ((uint64_t)time_passed > 12 * 60 * 60)
+                goto ret;
+
+        while (full_read(fd, &lease, sizeof(lease)) == sizeof(lease)) {
+                uint32_t y = ntohl(lease.lease_nip);
+                if (y >= server_config.start_ip && y <= server_config.end_ip) {
+                        signed_leasetime_t expires = ntohl(lease.expires) - (signed_leasetime_t)time_passed;
+                        uint32_t static_nip;
+
+                        if (expires <= 0)
+                                /* We keep expired leases: add_lease() will add
+                                 * a lease with 0 seconds remaining.
+                                 * Fewer IP address changes this way for mass reboot scenario.
+                                 */
+                                expires = 0;
+
+                        /* Check if there is a different static lease for this IP or MAC */
+                        static_nip = get_static_nip_by_mac(server_config.static_leases, lease.lease_mac);
+                        if (static_nip) {
+                                /* NB: we do not add lease even if static_nip == lease.lease_nip.
+                                 */
+                                continue;
+                        }
+                        if (is_nip_reserved(server_config.static_leases, lease.lease_nip))
+                                continue;
+
+                        /* NB: add_lease takes "relative time", IOW,
+                         * lease duration, not lease deadline. */
+                        if (add_lease(lease.lease_mac, lease.lease_nip,
+                                        expires,
+                                        lease.hostname, sizeof(lease.hostname)
+                                ) == 0
+                        ) {
+                                bb_error_msg("too many leases while loading %s", file);
+                                break;
+                        }
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
+                        i++;
+#endif
+                }
+        }
+        log1("read %d leases", i);
+ ret:
+        close(fd);
+}
 
 /* Send a packet to a specific mac address and ip address by creating our own ip packet */
 static void send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadcast)
@@ -290,12 +511,10 @@ static NOINLINE void send_inform(struct dhcp_packet *oldpacket)
         send_packet(&packet, /*force_bcast:*/ 0);
 }
 
-
 /* globals */
 struct dyn_lease *g_leases;
 /* struct server_config_t server_config is in bb_common_bufsiz1 */
 
-
 int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 {