ipcpd: Add ipcpd over UDP/IPv6

This adds an IPCP that runs over UDP/IPv6. It's structured like the
eth-dix and eth-llc in that it builds two separate binaries:
ipcpd-udp4 and ipcpd-udp6. The IRM CLI is backwards compatible in that
type 'udp' will resolve to type 'udp4'.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 1197 insertions, 0 deletions

diff --git a/src/ipcpd/udp/udp.c b/src/ipcpd/udp/udp.c
new file mode 100644
index 00000000..d6d38362
--- /dev/null
+++ b/src/ipcpd/udp/udp.c
@@ -0,0 +1,1197 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2024
+ *
+ * IPC process over UDP
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#include "config.h"
+
+#include <ouroboros/bitmap.h>
+#include <ouroboros/endian.h>
+#include <ouroboros/hash.h>
+#include <ouroboros/list.h>
+#include <ouroboros/utils.h>
+#include <ouroboros/dev.h>
+#include <ouroboros/fqueue.h>
+#include <ouroboros/errno.h>
+#include <ouroboros/logs.h>
+#include <ouroboros/pthread.h>
+
+#include "ipcp.h"
+#include "shim-data.h"
+
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+
+#define FLOW_REQ                 1
+#define FLOW_REPLY               2
+
+#define OUR_HEADER_LEN           sizeof(uint32_t) /* adds eid */
+
+#define IPCP_UDP_BUF_SIZE        IPCP_UDP_MAX_PACKET_SIZE
+#define IPCP_UDP_MSG_SIZE        IPCP_UDP_MAX_PACKET_SIZE
+
+#define DNS_TTL                  86400
+
+#define SADDR                    ((struct sockaddr *) &udp_data.s_saddr)
+#define SADDR_SIZE               (sizeof(udp_data.s_saddr))
+#define LOCAL_IP                 (udp_data.s_saddr.sin_addr.s_addr)
+
+#define MGMT_EID                 0
+#define MGMT_FRAME_SIZE          (sizeof(struct mgmt_msg))
+#define MGMT_FRAME_BUF_SIZE      2048
+
+#ifdef __linux__
+#define SENDTO_FLAGS MSG_CONFIRM
+#else
+#define SENDTO_FLAGS 0
+#endif
+
+/* Keep order for alignment. */
+struct mgmt_msg {
+        uint32_t eid;
+        uint32_t s_eid;
+        uint32_t d_eid;
+        uint8_t  code;
+        int8_t   response;
+        /* QoS parameters from spec */
+        uint8_t  availability;
+        uint8_t  in_order;
+        uint64_t bandwidth;
+        uint32_t delay;
+        uint32_t loss;
+        uint32_t ber;
+        uint32_t max_gap;
+        uint32_t timeout;
+        uint16_t cypher_s;
+
+} __attribute__((packed));
+
+struct mgmt_frame {
+        struct list_head  next;
+        struct __SOCKADDR r_saddr;
+        uint8_t           buf[MGMT_FRAME_BUF_SIZE];
+        size_t            len;
+};
+
+/* UDP flow */
+struct uf {
+        int               d_eid;
+        struct __SOCKADDR r_saddr;
+};
+
+struct {
+        struct shim_data * shim_data;
+
+        struct __ADDR      dns_addr;
+        struct __SOCKADDR  s_saddr;
+        int                s_fd;
+
+        fset_t *           np1_flows;
+        struct uf          fd_to_uf[SYS_MAX_FLOWS];
+        pthread_rwlock_t   flows_lock;
+
+        pthread_t          packet_writer[IPCP_UDP_WR_THR];
+        pthread_t          packet_reader[IPCP_UDP_RD_THR];
+
+        /* Handle mgmt frames in a different thread */
+        pthread_t          mgmt_handler;
+        pthread_mutex_t    mgmt_lock;
+        pthread_cond_t     mgmt_cond;
+        struct list_head   mgmt_frames;
+} udp_data;
+
+static const char * __inet_ntop(const struct __ADDR * addr,
+                                char *                buf)
+{
+        return inet_ntop(__AF, addr, buf, __ADDRSTRLEN);
+}
+
+static int udp_data_init(void)
+{
+        int                i;
+        pthread_condattr_t cattr;
+
+        if (pthread_rwlock_init(&udp_data.flows_lock, NULL))
+                goto fail_rwlock_init;
+
+        if (pthread_condattr_init(&cattr))
+                goto fail_condattr;
+#ifndef __APPLE__
+        pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
+#endif
+        if (pthread_cond_init(&udp_data.mgmt_cond, &cattr))
+                goto fail_mgmt_cond;
+
+        if (pthread_mutex_init(&udp_data.mgmt_lock, NULL))
+                goto fail_mgmt_lock;
+
+        for (i = 0; i < SYS_MAX_FLOWS; ++i)
+                udp_data.fd_to_uf[i].d_eid = -1;
+
+        udp_data.np1_flows = fset_create();
+        if (udp_data.np1_flows == NULL)
+                goto fail_fset;
+
+        udp_data.shim_data = shim_data_create();
+        if (udp_data.shim_data == NULL)
+                goto fail_data;
+
+        pthread_condattr_destroy(&cattr);
+
+        list_head_init(&udp_data.mgmt_frames);
+
+        return 0;
+
+ fail_data:
+        fset_destroy(udp_data.np1_flows);
+ fail_fset:
+        pthread_mutex_destroy(&udp_data.mgmt_lock);
+ fail_mgmt_lock:
+        pthread_cond_destroy(&udp_data.mgmt_cond);
+ fail_mgmt_cond:
+        pthread_condattr_destroy(&cattr);
+ fail_condattr:
+        pthread_rwlock_destroy(&udp_data.flows_lock);
+ fail_rwlock_init:
+        return -1;
+}
+
+static void udp_data_fini(void)
+{
+        shim_data_destroy(udp_data.shim_data);
+
+        fset_destroy(udp_data.np1_flows);
+
+        pthread_rwlock_destroy(&udp_data.flows_lock);
+        pthread_cond_destroy(&udp_data.mgmt_cond);
+        pthread_mutex_destroy(&udp_data.mgmt_lock);
+}
+
+static int udp_ipcp_port_alloc(const struct __SOCKADDR * r_saddr,
+                               uint32_t                  s_eid,
+                               const uint8_t *           dst,
+                               qosspec_t                 qs,
+                               const buffer_t *          data)
+{
+        uint8_t *         buf;
+        struct mgmt_msg * msg;
+        size_t            len;
+
+        assert(data->len > 0 ? data->data != NULL : data->data == NULL);
+
+        len = sizeof(*msg) + ipcp_dir_hash_len();
+
+        buf = malloc(len + data->len);
+        if (buf == NULL)
+                return -1;
+
+        msg               = (struct mgmt_msg *) buf;
+        msg->eid          = hton32(MGMT_EID);
+        msg->code         = FLOW_REQ;
+        msg->s_eid        = hton32(s_eid);
+        msg->delay        = hton32(qs.delay);
+        msg->bandwidth    = hton64(qs.bandwidth);
+        msg->availability = qs.availability;
+        msg->loss         = hton32(qs.loss);
+        msg->ber          = hton32(qs.ber);
+        msg->in_order     = qs.in_order;
+        msg->max_gap      = hton32(qs.max_gap);
+        msg->cypher_s     = hton16(qs.cypher_s);
+        msg->timeout      = hton32(qs.timeout);
+
+        memcpy(msg + 1, dst, ipcp_dir_hash_len());
+        if (data->len > 0)
+                memcpy(buf + len, data->data, data->len);
+
+        if (sendto(udp_data.s_fd, msg, len + data->len,
+                   SENDTO_FLAGS,
+                   (const struct sockaddr *) r_saddr, sizeof(*r_saddr)) < 0) {
+                log_err("Failed to send flow allocation request: %s.",
+                        strerror(errno));
+                free(buf);
+                return -1;
+        }
+
+        free(buf);
+
+        return 0;
+}
+
+static int udp_ipcp_port_alloc_resp(const struct __SOCKADDR * r_saddr,
+                                    uint32_t                  s_eid,
+                                    uint32_t                  d_eid,
+                                    int8_t                    response,
+                                    const buffer_t *          data)
+{
+        struct mgmt_msg * msg;
+
+        msg = malloc(sizeof(*msg) + data->len);
+        if (msg == NULL)
+                return -1;
+
+        msg->eid      = hton32(MGMT_EID);
+        msg->code     = FLOW_REPLY;
+        msg->s_eid    = hton32(s_eid);
+        msg->d_eid    = hton32(d_eid);
+        msg->response = response;
+
+        if (data->len > 0)
+                memcpy(msg + 1, data->data, data->len);
+
+        if (sendto(udp_data.s_fd, msg, sizeof(*msg) + data->len,
+                   SENDTO_FLAGS,
+                   (const struct sockaddr *) r_saddr, sizeof(*r_saddr)) < 0 ) {
+                free(msg);
+                return -1;
+        }
+
+        free(msg);
+
+        return 0;
+}
+
+static int udp_ipcp_port_req(struct __SOCKADDR * c_saddr,
+                             int                 d_eid,
+                             const uint8_t *     dst,
+                             qosspec_t           qs,
+                             const buffer_t *    data)
+{
+        int fd;
+
+        fd = ipcp_wait_flow_req_arr(dst, qs, IPCP_UDP_MPL, data);
+        if (fd < 0) {
+                log_err("Could not get new flow from IRMd.");
+                return -1;
+        }
+
+        pthread_rwlock_wrlock(&udp_data.flows_lock);
+
+        udp_data.fd_to_uf[fd].r_saddr = *c_saddr;
+        udp_data.fd_to_uf[fd].d_eid   = d_eid;
+
+        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+        log_dbg("Pending allocation request, fd %d, remote eid %d.",
+                fd, d_eid);
+
+        return 0;
+}
+
+static int udp_ipcp_port_alloc_reply(const struct __SOCKADDR * saddr,
+                                     uint32_t                  s_eid,
+                                     uint32_t                  d_eid,
+                                     int8_t                    response,
+                                     const buffer_t *          data)
+{
+        time_t mpl = IPCP_UDP_MPL;
+
+        pthread_rwlock_wrlock(&udp_data.flows_lock);
+
+        if (memcmp(&udp_data.fd_to_uf[s_eid].r_saddr, saddr, sizeof(*saddr))) {
+                char ipstr[__ADDRSTRLEN];
+                pthread_rwlock_unlock(&udp_data.flows_lock);
+                #ifdef BUILD_IPCP_UDP4
+                __inet_ntop(&saddr->sin_addr, ipstr);
+                #else
+                __inet_ntop(&saddr->sin6_addr, ipstr);
+                #endif
+                log_err("Flow allocation reply for %u from wrong source %s.",
+                        s_eid, ipstr);
+                return -1;
+        }
+
+        if (response == 0)
+                udp_data.fd_to_uf[s_eid].d_eid = d_eid;
+
+        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+        if (ipcp_flow_alloc_reply(s_eid, response, mpl, data) < 0) {
+                log_err("Failed to reply to flow allocation.");
+                return -1;
+        }
+
+        log_dbg("Flow allocation completed on eids (%d, %d).",
+                 s_eid, d_eid);
+
+        return 0;
+}
+
+static int udp_ipcp_mgmt_frame(struct __SOCKADDR c_saddr,
+                               const uint8_t *   buf,
+                               size_t            len)
+{
+        struct mgmt_msg * msg;
+        size_t            msg_len;
+        qosspec_t         qs;
+        buffer_t          data;
+
+        msg = (struct mgmt_msg *) buf;
+
+        switch (msg->code) {
+        case FLOW_REQ:
+                msg_len = sizeof(*msg) + ipcp_dir_hash_len();
+
+                assert(len >= msg_len);
+
+                data.len  = len - msg_len;
+                data.data = (uint8_t *) buf + msg_len;
+
+
+                qs.delay        = ntoh32(msg->delay);
+                qs.bandwidth    = ntoh64(msg->bandwidth);
+                qs.availability = msg->availability;
+                qs.loss         = ntoh32(msg->loss);
+                qs.ber          = ntoh32(msg->ber);
+                qs.in_order     = msg->in_order;
+                qs.max_gap      = ntoh32(msg->max_gap);
+                qs.cypher_s     = ntoh16(msg->cypher_s);
+                qs.timeout      = ntoh32(msg->timeout);
+
+                return udp_ipcp_port_req(&c_saddr, ntoh32(msg->s_eid),
+                                         (uint8_t *) (msg + 1), qs,
+                                          &data);
+        case FLOW_REPLY:
+                assert(len >= sizeof(*msg));
+
+                data.len  = len - sizeof(*msg);
+                data.data = (uint8_t *) buf + sizeof(*msg);
+
+                return udp_ipcp_port_alloc_reply(&c_saddr,
+                                                 ntoh32(msg->s_eid),
+                                                 ntoh32(msg->d_eid),
+                                                 msg->response,
+                                                 &data);
+        default:
+                log_err("Unknown message received %d.", msg->code);
+                return -1;
+        }
+}
+
+static void * udp_ipcp_mgmt_handler(void * o)
+{
+        (void) o;
+
+        pthread_cleanup_push(__cleanup_mutex_unlock, &udp_data.mgmt_lock);
+
+        while (true) {
+                struct mgmt_frame * frame;
+
+                pthread_mutex_lock(&udp_data.mgmt_lock);
+
+                while (list_is_empty(&udp_data.mgmt_frames))
+                        pthread_cond_wait(&udp_data.mgmt_cond,
+                                          &udp_data.mgmt_lock);
+
+                frame = list_first_entry((&udp_data.mgmt_frames),
+                                         struct mgmt_frame, next);
+                assert(frame != NULL);
+                list_del(&frame->next);
+
+                pthread_mutex_unlock(&udp_data.mgmt_lock);
+
+                udp_ipcp_mgmt_frame(frame->r_saddr, frame->buf, frame->len);
+
+                free(frame);
+        }
+
+        pthread_cleanup_pop(false);
+
+        return (void *) 0;
+}
+
+static void * udp_ipcp_packet_reader(void * o)
+{
+        uint8_t    buf[IPCP_UDP_MAX_PACKET_SIZE];
+        uint8_t *  data;
+        ssize_t    n;
+        uint32_t   eid;
+        uint32_t * eid_p;
+
+        (void) o;
+
+        ipcp_lock_to_core();
+
+        data  = buf + sizeof(uint32_t);
+        eid_p = (uint32_t *) buf;
+
+        while (true) {
+                struct mgmt_frame *  frame;
+                struct __SOCKADDR    r_saddr;
+                socklen_t            len;
+                struct shm_du_buff * sdb;
+                uint8_t *            head;
+
+                len = sizeof(r_saddr);
+
+                n = recvfrom(udp_data.s_fd, buf, IPCP_UDP_MAX_PACKET_SIZE, 0,
+                             (struct sockaddr *) &r_saddr, &len);
+                if (n < 0)
+                        continue;
+
+                if (n == 0)
+                        log_dbg("Got a 0 frame.");
+
+                if ((size_t) n < sizeof(eid)) {
+                        log_dbg("Dropped bad frame.");
+                        continue;
+                }
+
+                eid = ntoh32(*eid_p);
+
+                /* pass onto mgmt queue */
+                if (eid == MGMT_EID) {
+                        if ((size_t) n < MGMT_FRAME_SIZE) {
+                                log_warn("Dropped runt mgmt frame.");
+                                continue;
+                        }
+
+                        frame = malloc(sizeof(*frame));
+                        if (frame == NULL)
+                                continue;
+
+                        memcpy(frame->buf, buf, n);
+                        memcpy(&frame->r_saddr, &r_saddr, sizeof(r_saddr));
+                        frame->len = n;
+
+                        pthread_mutex_lock(&udp_data.mgmt_lock);
+                        list_add(&frame->next, &udp_data.mgmt_frames);
+                        pthread_cond_signal(&udp_data.mgmt_cond);
+                        pthread_mutex_unlock(&udp_data.mgmt_lock);
+                        continue;
+                }
+
+                n-= sizeof(eid);
+
+                if (ipcp_sdb_reserve(&sdb, n))
+                        continue;
+
+                head = shm_du_buff_head(sdb);
+                memcpy(head, data, n);
+                if (np1_flow_write(eid, sdb) < 0)
+                        ipcp_sdb_release(sdb);
+        }
+
+        return (void *) 0;
+}
+
+static void cleanup_fqueue(void * fq)
+{
+        fqueue_destroy((fqueue_t *) fq);
+}
+
+static void cleanup_sdb(void * sdb)
+{
+        ipcp_sdb_release((struct shm_du_buff *) sdb);
+}
+
+static void * udp_ipcp_packet_writer(void * o)
+{
+        fqueue_t * fq;
+
+        fq = fqueue_create();
+        if (fq == NULL)
+                return (void *) -1;
+
+        (void) o;
+
+        ipcp_lock_to_core();
+
+        pthread_cleanup_push(cleanup_fqueue, fq);
+
+        while (true) {
+                struct __SOCKADDR saddr;
+                int               eid;
+                int               fd;
+                fevent(udp_data.np1_flows, fq, NULL);
+                while ((fd = fqueue_next(fq)) >= 0) {
+                        struct shm_du_buff * sdb;
+                        uint8_t *            buf;
+                        uint16_t             len;
+
+                        if (fqueue_type(fq) != FLOW_PKT)
+                                continue;
+
+                        if (np1_flow_read(fd, &sdb)) {
+                                log_dbg("Bad read from fd %d.", fd);
+                                continue;
+                        }
+
+                        len = shm_du_buff_len(sdb);
+                        if (len > IPCP_UDP_MAX_PACKET_SIZE) {
+                                log_dbg("Packet length exceeds MTU.");
+                                ipcp_sdb_release(sdb);
+                                continue;
+                        }
+
+                        buf = shm_du_buff_head_alloc(sdb, OUR_HEADER_LEN);
+                        if (buf == NULL) {
+                                log_dbg("Failed to allocate header.");
+                                ipcp_sdb_release(sdb);
+                                continue;
+                        }
+
+                        pthread_rwlock_rdlock(&udp_data.flows_lock);
+
+                        eid = hton32(udp_data.fd_to_uf[fd].d_eid);
+                        saddr = udp_data.fd_to_uf[fd].r_saddr;
+
+                        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+                        memcpy(buf, &eid, sizeof(eid));
+
+                        pthread_cleanup_push(cleanup_sdb, sdb);
+
+                        if (sendto(udp_data.s_fd, buf, len + OUR_HEADER_LEN,
+                                   SENDTO_FLAGS,
+                                   (const struct sockaddr *) &saddr,
+                                   sizeof(saddr)) < 0)
+                                log_err("Failed to send packet.");
+
+                        pthread_cleanup_pop(true);
+                }
+        }
+
+        pthread_cleanup_pop(true);
+
+        return (void *) 1;
+}
+
+static bool is_addr_specified(const struct __ADDR * addr)
+{
+#ifdef BUILD_IPCP_UDP4
+        return addr->s_addr != 0;
+#else
+        return !IN6_IS_ADDR_UNSPECIFIED(addr);
+#endif
+}
+
+static int udp_ipcp_bootstrap(struct ipcp_config * conf)
+{
+        char ipstr[__ADDRSTRLEN];
+        char dnsstr[__ADDRSTRLEN];
+        int  i = 1;
+#ifdef BUILD_IPCP_UDP4
+        struct udp4_config * udp;
+        udp = &conf->udp4;
+#else
+        struct udp6_config * udp;
+        udp = &conf->udp6;
+#endif
+
+        assert(conf != NULL);
+        assert(conf->type == THIS_TYPE);
+        assert(conf->layer_info.dir_hash_algo == (enum pol_dir_hash) HASH_MD5);
+
+        if (__inet_ntop(&udp->ip_addr, ipstr) == NULL) {
+                log_err("Failed to convert IP address.");
+                return -1;
+        }
+
+        if (is_addr_specified(&udp->dns_addr)) {
+                if (__inet_ntop(&udp->dns_addr, dnsstr) == NULL) {
+                        log_err("Failed to convert DNS address.");
+                        return -1;
+                }
+#ifndef HAVE_DDNS
+                log_warn("DNS disabled at compile time, address ignored.");
+#endif
+        } else {
+                strcpy(dnsstr, "not set");
+        }
+
+        /* UDP listen server */
+        udp_data.s_fd = socket(__AF, SOCK_DGRAM, IPPROTO_UDP);
+        if (udp_data.s_fd < 0) {
+                log_err("Can't create socket: %s", strerror(errno));
+                goto fail_socket;
+        }
+
+        memset((char *) &udp_data.s_saddr, 0, sizeof(udp_data.s_saddr));
+#ifdef BUILD_IPCP_UDP4
+        udp_data.s_saddr.sin_family  = AF_INET;
+        udp_data.s_saddr.sin_addr   = udp->ip_addr;
+        udp_data.s_saddr.sin_port   = htons(udp->port);
+#else
+        udp_data.s_saddr.sin6_family = AF_INET6;
+        udp_data.s_saddr.sin6_addr   = udp->ip_addr;
+        udp_data.s_saddr.sin6_port   = htons(udp->port);
+#endif
+        if (bind(udp_data.s_fd, SADDR, SADDR_SIZE) < 0) {
+                log_err("Couldn't bind to %s:%d. %s.",
+                        ipstr, udp->port, strerror(errno));
+                goto fail_bind;
+        }
+
+        udp_data.dns_addr = udp->dns_addr;
+
+        if (pthread_create(&udp_data.mgmt_handler, NULL,
+                           udp_ipcp_mgmt_handler, NULL)) {
+                log_err("Failed to create management thread.");
+                goto fail_bind;
+        }
+
+        for (i = 0; i < IPCP_UDP_RD_THR; ++i) {
+                if (pthread_create(&udp_data.packet_reader[i], NULL,
+                                   udp_ipcp_packet_reader, NULL)) {
+                        log_err("Failed to create reader thread.");
+                        goto fail_packet_reader;
+                }
+        }
+
+        for (i = 0; i < IPCP_UDP_WR_THR; ++i) {
+                if (pthread_create(&udp_data.packet_writer[i], NULL,
+                        udp_ipcp_packet_writer, NULL)) {
+                        log_err("Failed to create writer thread.");
+                        goto fail_packet_writer;
+                }
+        }
+
+        log_dbg("Bootstrapped " TYPE_STR " with pid %d.", getpid());
+        log_dbg("Bound to IP address %s.", ipstr);
+        log_dbg("Using port %u.", udp->port);
+        if (is_addr_specified(&udp_data.dns_addr))
+                log_dbg("DNS server address is %s.", dnsstr);
+        else
+                log_dbg("DNS server not in use.");
+
+        return 0;
+
+ fail_packet_writer:
+        while (i-- > 0) {
+                pthread_cancel(udp_data.packet_writer[i]);
+                pthread_join(udp_data.packet_writer[i], NULL);
+        }
+        i = IPCP_UDP_RD_THR;
+ fail_packet_reader:
+        while (i-- > 0) {
+                pthread_cancel(udp_data.packet_reader[i]);
+                pthread_join(udp_data.packet_reader[i], NULL);
+        }
+        pthread_cancel(udp_data.mgmt_handler);
+        pthread_join(udp_data.mgmt_handler, NULL);
+ fail_bind:
+        close(udp_data.s_fd);
+ fail_socket:
+        return -1;
+}
+
+#ifdef HAVE_DDNS
+/* FIXME: Dependency on nsupdate to be removed in the end */
+/* NOTE: Disgusted with this crap */
+static int ddns_send(char * cmd)
+{
+        pid_t pid;
+        int   wstatus;
+        int   pipe_fd[2];
+        char * argv[] = {NSUPDATE_EXEC, 0};
+        char * envp[] = {0};
+
+        if (pipe(pipe_fd)) {
+                log_err("Failed to create pipe: %s.", strerror(errno));
+                return -1;
+        }
+
+        pid = fork();
+        if (pid == -1) {
+                log_err("Failed to fork: %s.", strerror(errno));
+                close(pipe_fd[0]);
+                close(pipe_fd[1]);
+                return -1;
+        }
+
+        if (pid == 0) {
+                close(pipe_fd[1]);
+                dup2(pipe_fd[0], 0);
+                execve(argv[0], &argv[0], envp);
+                log_err("Failed to execute: %s", strerror(errno));
+                exit(1);
+        }
+
+        close(pipe_fd[0]);
+
+        if (write(pipe_fd[1], cmd, strlen(cmd)) == -1) {
+                log_err("Failed to communicate with nsupdate: %s.",
+                        strerror(errno));
+                close(pipe_fd[1]);
+                return -1;
+        }
+
+        waitpid(pid, &wstatus, 0);
+        if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0)
+                log_dbg("Succesfully communicated with DNS server.");
+        else
+                log_err("Failed to register with DNS server.");
+
+        close(pipe_fd[1]);
+
+        return 0;
+}
+
+static struct __ADDR ddns_resolve(char *        name,
+                                  struct __ADDR dns_addr)
+{
+        pid_t          pid      = -1;
+        int            wstatus;
+        int            pipe_fd[2];
+        char           dnsstr[__ADDRSTRLEN];
+        char           buf[IPCP_UDP_BUF_SIZE];
+        ssize_t        count    = 0;
+        char *         substr   = NULL;
+        char *         substr2  = NULL;
+        char *         addr_str = "Address:";
+        struct __ADDR  ip_addr  = __ADDR_ANY_INIT;
+
+        if (__inet_ntop(&dns_addr, dnsstr) == NULL)
+                return ip_addr;
+
+        if (pipe(pipe_fd)) {
+                log_err("Failed to create pipe: %s.", strerror(errno));
+                return ip_addr;
+        }
+
+        pid = fork();
+        if (pid == -1) {
+                log_err("Failed to fork: %s.", strerror(errno));
+                close(pipe_fd[0]);
+                close(pipe_fd[1]);
+                return ip_addr;
+        }
+
+        if (pid == 0) {
+                char * argv[] = {NSLOOKUP_EXEC, name, dnsstr, 0};
+                char * envp[] = {0};
+
+                close(pipe_fd[0]);
+                dup2(pipe_fd[1], 1);
+                execve(argv[0], &argv[0], envp);
+                log_err("Failed to execute: %s", strerror(errno));
+                exit(1);
+        }
+
+        close(pipe_fd[1]);
+
+        count = read(pipe_fd[0], buf, IPCP_UDP_BUF_SIZE - 1);
+        if (count <= 0) {
+                log_err("Failed to communicate with nslookup.");
+                close(pipe_fd[0]);
+                return ip_addr;
+        }
+
+        close(pipe_fd[0]);
+
+        waitpid(pid, &wstatus, 0);
+        if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0 &&
+            count != IPCP_UDP_BUF_SIZE - 1)
+                log_dbg("Succesfully communicated with nslookup.");
+        else
+                log_err("Failed to resolve DNS address.");
+
+        buf[count] = '\0';
+        substr = strtok(buf, "\n");
+        while (substr != NULL) {
+                substr2 = substr;
+                substr = strtok(NULL, "\n");
+        }
+
+        if (substr2 == NULL || strstr(substr2, addr_str) == NULL) {
+                log_err("Failed to resolve DNS address.");
+                return ip_addr;
+        }
+
+        if (inet_pton(__AF, substr2 + strlen(addr_str) + 1, &ip_addr) != 1) {
+                log_err("Failed to resolve DNS address.");
+                assert(!is_addr_specified(&ip_addr));
+                return ip_addr;
+        }
+
+        return ip_addr;
+}
+#endif
+
+static int udp_ipcp_reg(const uint8_t * hash)
+{
+#ifdef HAVE_DDNS
+        char          ipstr[__ADDRSTRLEN];
+        char          dnsstr[__ADDRSTRLEN];
+        char          cmd[1000];
+        struct __ADDR dns_addr;
+        struct __ADDR ip_addr;
+#endif
+        char *   hashstr;
+
+        hashstr = malloc(ipcp_dir_hash_strlen() + 1);
+        if (hashstr == NULL) {
+                log_err("Failed to malloc hashstr.");
+                return -1;
+        }
+
+        assert(hash);
+
+        ipcp_hash_str(hashstr, hash);
+
+        if (shim_data_reg_add_entry(udp_data.shim_data, hash)) {
+                log_err("Failed to add " HASH_FMT32 " to local registry.",
+                        HASH_VAL32(hash));
+                free(hashstr);
+                return -1;
+        }
+
+#ifdef HAVE_DDNS
+        /* register application with DNS server */
+
+        dns_addr = udp_data.dns_addr;
+
+        if (is_addr_specified(&dns_addr)) {
+#ifdef BUILD_IPCP_UDP4
+                ip_addr = udp_data.s_saddr.sin_addr;
+#else
+                ip_addr = udp_data.s_saddr.sin6_addr;
+#endif
+                if (__inet_ntop(&ip_addr, ipstr) == NULL) {
+                        log_err("Failed to convert IP address to string.");
+                        free(hashstr);
+                        return -1;
+                }
+
+                if (__inet_ntop(&dns_addr, dnsstr) == NULL) {
+                        log_err("Failed to convert DNS address to string.");
+                        free(hashstr);
+                        return -1;
+                }
+
+                sprintf(cmd, "server %s\nupdate add %s %d A %s\nsend\nquit\n",
+                        dnsstr, hashstr, DNS_TTL, ipstr);
+
+                if (ddns_send(cmd)) {
+                        log_err("Failed to send DDNS message.");
+                        shim_data_reg_del_entry(udp_data.shim_data, hash);
+                        free(hashstr);
+                        return -1;
+                }
+        }
+#endif
+        free(hashstr);
+
+        return 0;
+}
+
+static int udp_ipcp_unreg(const uint8_t * hash)
+{
+#ifdef HAVE_DDNS
+        char          dnsstr[__ADDRSTRLEN];
+        /* max DNS name length + max IP length + max command length */
+        char          cmd[100];
+        struct __ADDR dns_addr;
+#endif
+        char * hashstr;
+
+        assert(hash);
+
+        hashstr = malloc(ipcp_dir_hash_strlen() + 1);
+        if (hashstr == NULL) {
+                log_err("Failed to malloc hashstr.");
+                return -1;
+        }
+
+        ipcp_hash_str(hashstr, hash);
+
+#ifdef HAVE_DDNS
+        /* unregister application with DNS server */
+
+        dns_addr = udp_data.dns_addr;
+
+        if (is_addr_specified(&dns_addr)) {
+                if (__inet_ntop(&dns_addr, dnsstr) == NULL) {
+                        log_err("Failed to convert DNS address to string.");
+                        free(hashstr);
+                        return -1;
+                }
+                sprintf(cmd, "server %s\nupdate delete %s A\nsend\nquit\n",
+                        dnsstr, hashstr);
+
+                ddns_send(cmd);
+        }
+#endif
+
+        shim_data_reg_del_entry(udp_data.shim_data, hash);
+
+        free(hashstr);
+
+        return 0;
+}
+
+static int udp_ipcp_query(const uint8_t * hash)
+{
+        struct addr        addr = {};
+        char *             hashstr;
+        struct addrinfo    hints;
+        struct addrinfo  * ai;
+#ifdef HAVE_DDNS
+        struct __ADDR      dns_addr = __ADDR_ANY_INIT;
+        struct __ADDR      ip_addr = __ADDR_ANY_INIT;
+#endif
+        assert(hash);
+
+        hashstr = malloc(ipcp_dir_hash_strlen() + 1);
+        if (hashstr == NULL) {
+                log_err("Failed to malloc hashstr.");
+                return -ENOMEM;
+        }
+
+        ipcp_hash_str(hashstr, hash);
+
+        if (shim_data_dir_has(udp_data.shim_data, hash)) {
+                free(hashstr);
+                return 0;
+        }
+
+#ifdef HAVE_DDNS
+        dns_addr = udp_data.dns_addr;
+
+        if (is_addr_specified(&dns_addr)) {
+                ip_addr = ddns_resolve(hashstr, dns_addr);
+                if (!is_addr_specified(&ip_addr)) {
+                        log_err("Could not resolve %s.", hashstr);
+                        free(hashstr);
+                        return -1;
+                }
+        } else {
+#endif
+                memset(&hints, 0, sizeof(hints));
+
+                hints.ai_family   = __AF;
+                if (getaddrinfo(hashstr, NULL, &hints, &ai) != 0) {
+                        log_err("Could not resolve %s: %s.", hashstr,
+                                gai_strerror(errno));
+                        free(hashstr);
+                        return -1;
+                }
+
+                if (ai->ai_family != __AF) {
+                        log_err("Wrong addres family for %s.", hashstr);
+                        freeaddrinfo(ai);
+                        free(hashstr);
+                        return -1;
+                }
+
+        #ifdef BUILD_IPCP_UDP4
+                addr.ip4 = ((struct sockaddr_in *) (ai->ai_addr))->sin_addr;
+        #else
+                addr.ip6 = ((struct sockaddr_in6 *) (ai->ai_addr))->sin6_addr;
+        #endif
+                freeaddrinfo(ai);
+#ifdef HAVE_DDNS
+        }
+#endif
+        if (shim_data_dir_add_entry(udp_data.shim_data, hash, addr)) {
+                log_err("Failed to add directory entry.");
+                free(hashstr);
+                return -1;
+        }
+
+        free(hashstr);
+
+        return 0;
+}
+
+static int udp_ipcp_flow_alloc(int              fd,
+                               const uint8_t *  dst,
+                               qosspec_t        qs,
+                               const buffer_t * data)
+{
+        struct __SOCKADDR r_saddr; /* Server address */
+        struct __ADDR     ip_addr;
+        struct addr       addr;
+        char              ipstr[__ADDRSTRLEN];
+
+        (void) qs;
+
+        assert(dst);
+
+        if (!shim_data_dir_has(udp_data.shim_data, dst)) {
+                log_err("Could not resolve destination.");
+                return -1;
+        }
+
+        addr = shim_data_dir_get_addr(udp_data.shim_data, dst);
+#ifdef BUILD_IPCP_UDP4
+        ip_addr = addr.ip4;
+#else
+        ip_addr = addr.ip6;
+#endif
+        if (__inet_ntop(&ip_addr, ipstr) == NULL) {
+                log_err("Could not convert IP address.");
+                return -1;
+        }
+
+        log_dbg("Destination " HASH_FMT32 " resolved at IP %s.",
+                HASH_VAL32(dst), ipstr);
+
+        memset((char *) &r_saddr, 0, sizeof(r_saddr));
+#ifdef BUILD_IPCP_UDP4
+        r_saddr.sin_family = AF_INET;
+        r_saddr.sin_addr   = addr.ip4;
+        r_saddr.sin_port   = udp_data.s_saddr.sin_port;
+#else
+        r_saddr.sin6_family = AF_INET6;
+        r_saddr.sin6_addr   = addr.ip6;
+        r_saddr.sin6_port   = udp_data.s_saddr.sin6_port;
+#endif
+
+        if (udp_ipcp_port_alloc(&r_saddr, fd, dst, qs, data) < 0) {
+                log_err("Could not allocate port.");
+                return -1;
+        }
+
+        pthread_rwlock_wrlock(&udp_data.flows_lock);
+
+        udp_data.fd_to_uf[fd].d_eid   = -1;
+        udp_data.fd_to_uf[fd].r_saddr = r_saddr;
+
+        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+        fset_add(udp_data.np1_flows, fd);
+
+        return 0;
+}
+
+static int udp_ipcp_flow_alloc_resp(int              fd,
+                                    int              resp,
+                                    const buffer_t * data)
+{
+        struct __SOCKADDR saddr;
+        int               d_eid;
+
+        if (ipcp_wait_flow_resp(fd) < 0) {
+                log_err("Failed to wait for flow response.");
+                return -1;
+        }
+
+        pthread_rwlock_rdlock(&udp_data.flows_lock);
+
+        saddr = udp_data.fd_to_uf[fd].r_saddr;
+        d_eid = udp_data.fd_to_uf[fd].d_eid;
+
+        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+        if (udp_ipcp_port_alloc_resp(&saddr, d_eid, fd, resp, data) < 0) {
+                fset_del(udp_data.np1_flows, fd);
+                log_err("Failed to respond to flow request.");
+                return -1;
+        }
+
+        fset_add(udp_data.np1_flows, fd);
+
+        return 0;
+}
+
+static int udp_ipcp_flow_dealloc(int fd)
+{
+        ipcp_flow_fini(fd);
+
+        fset_del(udp_data.np1_flows, fd);
+
+        pthread_rwlock_wrlock(&udp_data.flows_lock);
+
+        udp_data.fd_to_uf[fd].d_eid = -1;
+        memset(&udp_data.fd_to_uf[fd].r_saddr, 0, SADDR_SIZE);
+
+        pthread_rwlock_unlock(&udp_data.flows_lock);
+
+        ipcp_flow_dealloc(fd);
+
+        return 0;
+}
+
+static struct ipcp_ops udp_ops = {
+        .ipcp_bootstrap       = udp_ipcp_bootstrap,
+        .ipcp_enroll          = NULL,
+        .ipcp_connect         = NULL,
+        .ipcp_disconnect      = NULL,
+        .ipcp_reg             = udp_ipcp_reg,
+        .ipcp_unreg           = udp_ipcp_unreg,
+        .ipcp_query           = udp_ipcp_query,
+        .ipcp_flow_alloc      = udp_ipcp_flow_alloc,
+        .ipcp_flow_join       = NULL,
+        .ipcp_flow_alloc_resp = udp_ipcp_flow_alloc_resp,
+        .ipcp_flow_dealloc    = udp_ipcp_flow_dealloc
+};
+
+int main(int    argc,
+         char * argv[])
+{
+        int i;
+
+
+        if (udp_data_init() < 0) {
+                log_err("Failed to init udp data.");
+                goto fail_data_init;
+        }
+
+        if (ipcp_init(argc, argv, &udp_ops, THIS_TYPE) < 0) {
+                log_err("Failed to initialize IPCP.");
+                goto fail_init;
+        }
+
+        if (ipcp_start() < 0) {
+                log_err("Failed to start IPCP.");
+                goto fail_start;
+        }
+
+        ipcp_sigwait();
+
+        if (ipcp_get_state() == IPCP_SHUTDOWN) {
+                for (i = 0; i < IPCP_UDP_WR_THR; ++i)
+                        pthread_cancel(udp_data.packet_writer[i]);
+                for (i = 0; i < IPCP_UDP_RD_THR; ++i)
+                        pthread_cancel(udp_data.packet_reader[i]);
+                pthread_cancel(udp_data.mgmt_handler);
+
+                for (i = 0; i < IPCP_UDP_WR_THR; ++i)
+                        pthread_join(udp_data.packet_writer[i], NULL);
+                for (i = 0; i < IPCP_UDP_RD_THR; ++i)
+                        pthread_join(udp_data.packet_reader[i], NULL);
+                pthread_join(udp_data.mgmt_handler, NULL);
+                close(udp_data.s_fd);
+        }
+
+        ipcp_stop();
+
+        ipcp_fini();
+
+        udp_data_fini();
+
+        exit(EXIT_SUCCESS);
+
+ fail_start:
+        ipcp_fini();
+ fail_init:
+        udp_data_fini();
+ fail_data_init:
+        exit(EXIT_FAILURE);
+}