ipcpd: Restructure policy code

The policies were all in a single folder pol/, and have been moved to
a folder per component/mechanism to keep things a bit more orderly.

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

11 files changed, 1465 insertions, 0 deletions

diff --git a/src/ipcpd/unicast/pff/alternate.c b/src/ipcpd/unicast/pff/alternate.c
new file mode 100644
index 00000000..9f0a6279
--- /dev/null
+++ b/src/ipcpd/unicast/pff/alternate.c
@@ -0,0 +1,400 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Policy for PFF with alternate next hops
+ *
+ *    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/.
+ */
+
+#define _POSIX_C_SOURCE 200112L
+
+#include "config.h"
+
+#include <ouroboros/errno.h>
+#include <ouroboros/list.h>
+
+#include "pft.h"
+#include "alternate.h"
+
+#include <string.h>
+#include <assert.h>
+#include <pthread.h>
+
+struct nhop {
+        struct list_head next;
+        int              fd;
+};
+
+struct addr {
+        struct list_head next;
+        uint64_t         addr;
+};
+
+struct pff_i {
+        struct pft *     pft;
+
+        struct list_head addrs;
+
+        struct list_head nhops_down;
+
+        pthread_rwlock_t lock;
+};
+
+struct pff_ops alternate_pff_ops = {
+        .create            = alternate_pff_create,
+        .destroy           = alternate_pff_destroy,
+        .lock              = alternate_pff_lock,
+        .unlock            = alternate_pff_unlock,
+        .add               = alternate_pff_add,
+        .update            = alternate_pff_update,
+        .del               = alternate_pff_del,
+        .flush             = alternate_pff_flush,
+        .nhop              = alternate_pff_nhop,
+        .flow_state_change = alternate_flow_state_change
+};
+
+static int add_addr(struct pff_i * pff_i,
+                    uint64_t       addr)
+{
+        struct addr * a;
+
+        a = malloc(sizeof(*a));
+        if (a == NULL)
+                return -1;
+
+        a->addr = addr;
+
+        list_add(&a->next, &(pff_i->addrs));
+
+        return 0;
+}
+
+static void del_addr(struct pff_i * pff_i,
+                     uint64_t       addr)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        list_for_each_safe(p, h, &(pff_i->addrs)) {
+                struct addr * e = list_entry(p, struct addr, next);
+                if (e->addr == addr) {
+                        list_del(&e->next);
+                        free(e);
+                        return;
+                }
+        }
+}
+
+static void del_addrs(struct pff_i * pff_i)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        list_for_each_safe(p, h, &(pff_i->addrs)) {
+                struct addr * e = list_entry(p, struct addr, next);
+                list_del(&e->next);
+                free(e);
+        }
+}
+
+static void del_nhops_down(struct pff_i * pff_i)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        list_for_each_safe(p, h, &(pff_i->nhops_down)) {
+                struct nhop * e = list_entry(p, struct nhop, next);
+                list_del(&e->next);
+                free(e);
+        }
+}
+
+static int del_nhop_down(struct pff_i * pff_i,
+                         int            fd)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        list_for_each_safe(p, h, &(pff_i->nhops_down)) {
+                struct nhop * e = list_entry(p, struct nhop, next);
+                if (e->fd == fd) {
+                        list_del(&e->next);
+                        free(e);
+                        return 0;
+                }
+        }
+
+        return -1;
+}
+
+static int add_nhop_down(struct pff_i * pff_i,
+                         int            fd)
+{
+        struct nhop *      nhop;
+
+        nhop = malloc(sizeof(*nhop));
+        if (nhop == NULL)
+                return -1;
+
+        nhop->fd = fd;
+
+        list_add(&nhop->next, &(pff_i->nhops_down));
+
+        return 0;
+}
+
+static bool nhops_down_has(struct pff_i * pff_i,
+                           int            fd)
+{
+        struct list_head * pos = NULL;
+
+        list_for_each(pos, &pff_i->nhops_down) {
+                struct nhop * e = list_entry(pos, struct nhop, next);
+                if (e->fd == fd)
+                        return true;
+        }
+
+        return false;
+}
+
+static int add_to_pft(struct pff_i * pff_i,
+                      uint64_t       addr,
+                      int *          fd,
+                      size_t         len)
+{
+        int * fds;
+
+        assert(pff_i);
+        assert(len > 0);
+
+        fds = malloc(sizeof(*fds) * (len + 1));
+        if (fds == NULL)
+                goto fail_malloc;
+
+        memcpy(fds, fd, len * sizeof(*fds));
+        /* Put primary hop again at the end */
+        fds[len] = fds[0];
+
+        if (pft_insert(pff_i->pft, addr, fds, len))
+                goto fail_insert;
+
+        return 0;
+
+ fail_insert:
+        free(fds);
+ fail_malloc:
+        return -1;
+}
+
+struct pff_i * alternate_pff_create(void)
+{
+        struct pff_i * tmp;
+
+        tmp = malloc(sizeof(*tmp));
+        if (tmp == NULL)
+                goto fail_malloc;
+
+        if (pthread_rwlock_init(&tmp->lock, NULL))
+                goto fail_lock;
+
+        tmp->pft = pft_create(PFT_SIZE, false);
+        if (tmp->pft == NULL)
+                goto fail_pft;
+
+        list_head_init(&tmp->nhops_down);
+        list_head_init(&tmp->addrs);
+
+        return tmp;
+
+ fail_pft:
+        pthread_rwlock_destroy(&tmp->lock);
+ fail_lock:
+        free(tmp);
+ fail_malloc:
+        return NULL;
+}
+
+void alternate_pff_destroy(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_destroy(pff_i->pft);
+        del_nhops_down(pff_i);
+        del_addrs(pff_i);
+        pthread_rwlock_destroy(&pff_i->lock);
+        free(pff_i);
+}
+
+void alternate_pff_lock(struct pff_i * pff_i)
+{
+        pthread_rwlock_wrlock(&pff_i->lock);
+}
+
+void alternate_pff_unlock(struct pff_i * pff_i)
+{
+        pthread_rwlock_unlock(&pff_i->lock);
+}
+
+int alternate_pff_add(struct pff_i * pff_i,
+                      uint64_t       addr,
+                      int *          fd,
+                      size_t         len)
+{
+        assert(pff_i);
+        assert(len > 0);
+
+        if (add_to_pft(pff_i, addr, fd, len))
+                return -1;
+
+        if (add_addr(pff_i, addr)) {
+                pft_delete(pff_i->pft, addr);
+                return -1;
+        }
+
+        return 0;
+}
+
+int alternate_pff_update(struct pff_i * pff_i,
+                         uint64_t       addr,
+                         int *          fd,
+                         size_t         len)
+{
+        assert(pff_i);
+        assert(len > 0);
+
+        if (pft_delete(pff_i->pft, addr))
+                return -1;
+
+        if (add_to_pft(pff_i, addr, fd, len))
+                return -1;
+
+        return 0;
+}
+
+int alternate_pff_del(struct pff_i * pff_i,
+                      uint64_t       addr)
+{
+        assert(pff_i);
+
+        del_addr(pff_i, addr);
+
+        if (pft_delete(pff_i->pft, addr))
+                return -1;
+
+        return 0;
+}
+
+void alternate_pff_flush(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_flush(pff_i->pft);
+
+        del_nhops_down(pff_i);
+
+        del_addrs(pff_i);
+}
+
+int alternate_pff_nhop(struct pff_i * pff_i,
+                       uint64_t       addr)
+{
+        int    fd;
+        size_t len;
+        int *  fds;
+
+        assert(pff_i);
+
+        pthread_rwlock_rdlock(&pff_i->lock);
+
+        if (pft_lookup(pff_i->pft, addr, &fds, &len)) {
+                pthread_rwlock_unlock(&pff_i->lock);
+                return -1;
+        }
+
+        fd = *fds;
+
+        pthread_rwlock_unlock(&pff_i->lock);
+
+        return fd;
+}
+
+int alternate_flow_state_change(struct pff_i * pff_i,
+                                int            fd,
+                                bool           up)
+{
+        struct list_head * p;
+        size_t             len;
+        int *              fds;
+        size_t             i;
+        int                tmp;
+
+        assert(pff_i);
+
+        pthread_rwlock_wrlock(&pff_i->lock);
+
+        if (up) {
+                if (del_nhop_down(pff_i, fd)) {
+                        pthread_rwlock_unlock(&pff_i->lock);
+                        return -1;
+                }
+        } else {
+                if (add_nhop_down(pff_i, fd)) {
+                        pthread_rwlock_unlock(&pff_i->lock);
+                        return -1;
+                }
+        }
+
+        list_for_each(p, &pff_i->addrs) {
+                struct addr * e = list_entry(p, struct addr, next);
+                if (pft_lookup(pff_i->pft, e->addr, &fds, &len)) {
+                        pthread_rwlock_unlock(&pff_i->lock);
+                        return -1;
+                }
+
+                if (up) {
+                        /* It is using an alternate */
+                        if (fds[len] == fd && fds[0] != fd) {
+                                for (i = 0 ; i < len; i++) {
+                                        /* Found the primary */
+                                        if (fds[i] == fd) {
+                                                tmp = fds[0];
+                                                fds[0] = fds[i];
+                                                fds[i] = tmp;
+                                                break;
+                                        }
+                                }
+                        }
+                } else {
+                        /* Need to switch to a (different) alternate */
+                        if (fds[0] == fd) {
+                                for (i = 1; i < len; i++) {
+                                        /* Usable alternate */
+                                        if (!nhops_down_has(pff_i, fds[i])) {
+                                                tmp = fds[0];
+                                                fds[0] = fds[i];
+                                                fds[i] = tmp;
+                                                break;
+                                        }
+                                }
+                        }
+                }
+        }
+
+        pthread_rwlock_unlock(&pff_i->lock);
+
+        return 0;
+}
diff --git a/src/ipcpd/unicast/pff/alternate.h b/src/ipcpd/unicast/pff/alternate.h
new file mode 100644
index 00000000..294f48d9
--- /dev/null
+++ b/src/ipcpd/unicast/pff/alternate.h
@@ -0,0 +1,61 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Policy for PFF with alternate next hops
+ *
+ *    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/.
+ */
+
+#ifndef OUROBOROS_IPCPD_UNICAST_ALTERNATE_PFF_H
+#define OUROBOROS_IPCPD_UNICAST_ALTERNATE_PFF_H
+
+#include "ops.h"
+
+struct pff_i * alternate_pff_create(void);
+
+void           alternate_pff_destroy(struct pff_i * pff_i);
+
+void           alternate_pff_lock(struct pff_i * pff_i);
+
+void           alternate_pff_unlock(struct pff_i * pff_i);
+
+int            alternate_pff_add(struct pff_i * pff_i,
+                                 uint64_t       addr,
+                                 int *          fd,
+                                 size_t         len);
+
+int            alternate_pff_update(struct pff_i * pff_i,
+                                    uint64_t       addr,
+                                    int *          fd,
+                                    size_t         len);
+
+int            alternate_pff_del(struct pff_i * pff_i,
+                                 uint64_t       addr);
+
+void           alternate_pff_flush(struct pff_i * pff_i);
+
+/* Returns fd towards next hop */
+int            alternate_pff_nhop(struct pff_i * pff_i,
+                                  uint64_t       addr);
+
+int            alternate_flow_state_change(struct pff_i * pff_i,
+                                           int            fd,
+                                           bool           up);
+
+extern struct pff_ops alternate_pff_ops;
+
+#endif /* OUROBOROS_IPCPD_UNICAST_ALTERNATE_PFF_H */
diff --git a/src/ipcpd/unicast/pff/multipath.c b/src/ipcpd/unicast/pff/multipath.c
new file mode 100644
index 00000000..43135d27
--- /dev/null
+++ b/src/ipcpd/unicast/pff/multipath.c
@@ -0,0 +1,198 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Policy for PFF supporting multipath routing
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *    Nick Aerts        <nick.aerts@ugent.be>
+ *
+ * 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/.
+ */
+
+#define _POSIX_C_SOURCE 200112L
+
+#include "config.h"
+
+#include <ouroboros/errno.h>
+
+#include "pft.h"
+#include "multipath.h"
+
+#include <string.h>
+#include <assert.h>
+#include <pthread.h>
+
+struct pff_i {
+        struct pft *     pft;
+        pthread_rwlock_t lock;
+};
+
+struct pff_ops multipath_pff_ops = {
+        .create            = multipath_pff_create,
+        .destroy           = multipath_pff_destroy,
+        .lock              = multipath_pff_lock,
+        .unlock            = multipath_pff_unlock,
+        .add               = multipath_pff_add,
+        .update            = multipath_pff_update,
+        .del               = multipath_pff_del,
+        .flush             = multipath_pff_flush,
+        .nhop              = multipath_pff_nhop,
+        .flow_state_change = NULL
+};
+
+struct pff_i * multipath_pff_create(void)
+{
+        struct pff_i * tmp;
+
+        tmp = malloc(sizeof(*tmp));
+        if (tmp == NULL)
+                return NULL;
+
+        if (pthread_rwlock_init(&tmp->lock, NULL)) {
+                free(tmp);
+                return NULL;
+        }
+
+        tmp->pft = pft_create(PFT_SIZE, false);
+        if (tmp->pft == NULL) {
+                pthread_rwlock_destroy(&tmp->lock);
+                free(tmp);
+                return NULL;
+        }
+
+        return tmp;
+}
+
+void multipath_pff_destroy(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_destroy(pff_i->pft);
+
+        pthread_rwlock_destroy(&pff_i->lock);
+        free(pff_i);
+}
+
+void multipath_pff_lock(struct pff_i * pff_i)
+{
+        pthread_rwlock_wrlock(&pff_i->lock);
+}
+
+void multipath_pff_unlock(struct pff_i * pff_i)
+{
+        pthread_rwlock_unlock(&pff_i->lock);
+}
+
+int multipath_pff_add(struct pff_i * pff_i,
+                      uint64_t       addr,
+                      int *          fds,
+                      size_t         len)
+{
+        int * tmp;
+
+        assert(pff_i);
+        assert(fds);
+        assert(len > 0);
+
+        tmp = malloc(len * sizeof(*tmp));
+        if (tmp == NULL)
+                return -ENOMEM;
+
+        memcpy(tmp,fds, len * sizeof(*tmp));
+
+        if (pft_insert(pff_i->pft, addr, tmp, len)) {
+                free(tmp);
+                return -1;
+        }
+
+        return 0;
+}
+
+int multipath_pff_update(struct pff_i * pff_i,
+                         uint64_t       addr,
+                         int *          fds,
+                         size_t         len)
+{
+        int * tmp;
+
+        assert(pff_i);
+        assert(fds);
+        assert(len > 0);
+
+        tmp = malloc(sizeof(*tmp));
+        if (tmp == NULL)
+                return -ENOMEM;
+
+        memcpy(tmp,fds, len * sizeof(*tmp));
+
+        if (pft_delete(pff_i->pft, addr)) {
+                free(tmp);
+                return -1;
+        }
+
+        if (pft_insert(pff_i->pft, addr, tmp, 1)) {
+                free(tmp);
+                return -1;
+        }
+
+        return 0;
+}
+
+int multipath_pff_del(struct pff_i * pff_i,
+                      uint64_t       addr)
+{
+        assert(pff_i);
+
+        if (pft_delete(pff_i->pft, addr))
+                return -1;
+
+        return 0;
+}
+
+void multipath_pff_flush(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_flush(pff_i->pft);
+}
+
+int multipath_pff_nhop(struct pff_i * pff_i,
+                       uint64_t       addr)
+{
+        int    fd;
+        int *  fds;
+        size_t len;
+
+        assert(pff_i);
+
+        pthread_rwlock_rdlock(&pff_i->lock);
+
+        if (pft_lookup(pff_i->pft, addr, &fds, &len)) {
+                pthread_rwlock_unlock(&pff_i->lock);
+                return -1;
+        }
+
+        fd = *fds;
+
+        assert(len > 0);
+
+        /* Rotate fds left. */
+        memcpy(fds, fds + 1, (len - 1) * sizeof(*fds));
+        fds[len - 1] = fd;
+
+        pthread_rwlock_unlock(&pff_i->lock);
+
+        return fd;
+}
diff --git a/src/ipcpd/unicast/pff/multipath.h b/src/ipcpd/unicast/pff/multipath.h
new file mode 100644
index 00000000..4a5bcefb
--- /dev/null
+++ b/src/ipcpd/unicast/pff/multipath.h
@@ -0,0 +1,58 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Policy for PFF supporting multipath routing
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *    Nick Aerts        <nick.aerts@ugent.be>
+ *
+ * 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/.
+ */
+
+#ifndef OUROBOROS_IPCPD_UNICAST_MULTIPATH_PFF_H
+#define OUROBOROS_IPCPD_UNICAST_MULTIPATH_PFF_H
+
+#include "ops.h"
+
+struct pff_i * multipath_pff_create(void);
+
+void multipath_pff_destroy(struct pff_i * pff_i);
+
+void           multipath_pff_lock(struct pff_i * pff_i);
+
+void           multipath_pff_unlock(struct pff_i * pff_i);
+
+int            multipath_pff_add(struct pff_i * pff_i,
+                                 uint64_t       addr,
+                                 int *          fds,
+                                 size_t         len);
+
+int            multipath_pff_update(struct pff_i * pff_i,
+                                    uint64_t       addr,
+                                    int *          fds,
+                                    size_t         len);
+
+int            multipath_pff_del(struct pff_i * pff_i,
+                                 uint64_t       addr);
+
+void multipath_pff_flush(struct pff_i * pff_i);
+
+/* Returns fd towards next hop */
+int            multipath_pff_nhop(struct pff_i * pff_i,
+                                  uint64_t       addr);
+
+extern struct pff_ops multipath_pff_ops;
+
+#endif /* OUROBOROS_IPCPD_UNICAST_MULTIPATH_PFF_H */
diff --git a/src/ipcpd/unicast/pff/ops.h b/src/ipcpd/unicast/pff/ops.h
new file mode 100644
index 00000000..a46f3da8
--- /dev/null
+++ b/src/ipcpd/unicast/pff/ops.h
@@ -0,0 +1,63 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Pff policy ops
+ *
+ *    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/.
+ */
+
+#ifndef OUROBOROS_IPCPD_UNICAST_PFF_OPS_H
+#define OUROBOROS_IPCPD_UNICAST_PFF_OPS_H
+
+#include <stdbool.h>
+
+struct pff_i;
+
+struct pff_ops {
+        struct pff_i * (* create)(void);
+
+        void           (* destroy)(struct pff_i * pff_i);
+
+        void           (* lock)(struct pff_i * pff_i);
+
+        void           (* unlock)(struct pff_i * pff_i);
+
+        int            (* add)(struct pff_i * pff_i,
+                               uint64_t       addr,
+                               int *          fd,
+                               size_t         len);
+
+        int            (* update)(struct pff_i * pff_i,
+                                  uint64_t       addr,
+                                  int *          fd,
+                                  size_t         len);
+
+        int            (* del)(struct pff_i * pff_i,
+                               uint64_t       addr);
+
+        void           (* flush)(struct pff_i * pff_i);
+
+        int            (* nhop)(struct pff_i * pff_i,
+                                uint64_t       addr);
+
+        /* Optional operation. */
+        int            (* flow_state_change)(struct pff_i * pff_i,
+                                             int            fd,
+                                             bool           up);
+};
+
+#endif /* OUROBOROS_IPCPD_UNICAST_PFF_OPS_H */
diff --git a/src/ipcpd/unicast/pff/pft.c b/src/ipcpd/unicast/pff/pft.c
new file mode 100644
index 00000000..e42b4a98
--- /dev/null
+++ b/src/ipcpd/unicast/pff/pft.c
@@ -0,0 +1,223 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Packet forwarding table (PFT) with chaining on collisions
+ *
+ *    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/.
+ */
+
+#if defined(__linux__) || defined(__CYGWIN__)
+#define _DEFAULT_SOURCE
+#endif
+
+#include <ouroboros/list.h>
+#include <ouroboros/errno.h>
+#include <ouroboros/hash.h>
+
+#include "pft.h"
+
+#include <assert.h>
+#include <string.h>
+
+/* store <len> output fds for dst addr */
+struct pft_entry {
+        struct list_head next;
+        uint64_t         dst;
+        int *            fds;
+        size_t           len;
+};
+
+struct pft {
+        struct list_head * buckets;
+        bool               hash_key;
+        uint64_t           buckets_size;
+};
+
+struct pft * pft_create(uint64_t buckets,
+                        bool     hash_key)
+{
+        struct pft * tmp;
+        unsigned int i;
+
+        if (buckets == 0)
+                return NULL;
+
+        buckets--;
+        buckets |= buckets >> 1;
+        buckets |= buckets >> 2;
+        buckets |= buckets >> 4;
+        buckets |= buckets >> 8;
+        buckets |= buckets >> 16;
+        buckets |= buckets >> 32;
+        buckets++;
+
+        tmp = malloc(sizeof(*tmp));
+        if (tmp == NULL)
+                return NULL;
+
+        tmp->hash_key = hash_key;
+        tmp->buckets_size = buckets;
+
+        tmp->buckets = malloc(buckets * sizeof(*tmp->buckets));
+        if (tmp->buckets == NULL) {
+                free(tmp);
+                return NULL;
+        }
+
+        for (i = 0; i < buckets; i++)
+                list_head_init(&(tmp->buckets[i]));
+
+        return tmp;
+}
+
+void pft_destroy(struct pft * pft)
+{
+        assert(pft);
+        assert(pft->buckets);
+
+        pft_flush(pft);
+        free(pft->buckets);
+        free(pft);
+}
+
+void pft_flush(struct pft * pft)
+{
+        unsigned int       i;
+        struct list_head * p;
+        struct list_head * h;
+        struct pft_entry * entry;
+
+        assert(pft);
+
+        for (i = 0; i < pft->buckets_size; i++) {
+                list_for_each_safe(p, h, &(pft->buckets[i])) {
+                        entry = list_entry(p, struct pft_entry, next);
+                        list_del(&entry->next);
+                        free(entry->fds);
+                        free(entry);
+                }
+        }
+}
+
+static uint64_t hash(uint64_t key)
+{
+        void *   res;
+        uint64_t ret;
+        uint8_t  keys[4];
+
+        memcpy(keys, &key, 4);
+
+        mem_hash(HASH_MD5, &res, keys, 4);
+
+        ret = (* (uint64_t *) res);
+
+        free(res);
+
+        return ret;
+}
+
+static uint64_t calc_key(struct pft * pft,
+                         uint64_t     dst)
+{
+        if (pft->hash_key)
+                dst = hash(dst);
+
+        return (dst & (pft->buckets_size - 1));
+}
+
+int pft_insert(struct pft * pft,
+               uint64_t     dst,
+               int *        fds,
+               size_t       len)
+{
+        struct pft_entry * entry;
+        uint64_t           lookup_key;
+        struct list_head * p;
+
+        assert(pft);
+        assert(len > 0);
+
+        lookup_key = calc_key(pft, dst);
+
+        list_for_each(p, &(pft->buckets[lookup_key])) {
+                entry = list_entry(p, struct pft_entry, next);
+                if (entry->dst == dst)
+                        return -EPERM;
+        }
+
+        entry = malloc(sizeof(*entry));
+        if (entry == NULL)
+                return -ENOMEM;
+
+        entry->dst = dst;
+        entry->fds = fds;
+        entry->len = len;
+
+        list_add(&entry->next, &(pft->buckets[lookup_key]));
+
+        return 0;
+}
+
+int pft_lookup(struct pft * pft,
+               uint64_t     dst,
+               int **       fds,
+               size_t *     len)
+{
+        struct pft_entry * entry;
+        struct list_head * p;
+        uint64_t           lookup_key;
+
+        assert(pft);
+
+        lookup_key = calc_key(pft, dst);
+
+        list_for_each(p, &(pft->buckets[lookup_key])) {
+                entry = list_entry(p, struct pft_entry, next);
+                if (entry->dst == dst) {
+                        *fds = entry->fds;
+                        *len = entry->len;
+                        return 0;
+                }
+        }
+
+        return -1;
+}
+
+int pft_delete(struct pft * pft,
+               uint64_t     dst)
+{
+        struct pft_entry * entry;
+        uint64_t           lookup_key;
+        struct list_head * p;
+        struct list_head * h;
+
+        assert(pft);
+
+        lookup_key = calc_key(pft, dst);
+
+        list_for_each_safe(p, h, &(pft->buckets[lookup_key])) {
+                entry = list_entry(p, struct pft_entry, next);
+                if (entry->dst == dst) {
+                        list_del(&entry->next);
+                        free(entry->fds);
+                        free(entry);
+                        return 0;
+                }
+        }
+
+        return -1;
+}
diff --git a/src/ipcpd/unicast/pff/pft.h b/src/ipcpd/unicast/pff/pft.h
new file mode 100644
index 00000000..011ad414
--- /dev/null
+++ b/src/ipcpd/unicast/pff/pft.h
@@ -0,0 +1,55 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Packet forwarding table (PFT) with chaining on collisions
+ *
+ *    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/.
+ */
+
+#ifndef OUROBOROS_PFT_H
+#define OUROBOROS_PFT_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+struct pft;
+
+/* Buckets is rounded up to the nearest power of 2 */
+struct pft * pft_create(uint64_t buckets,
+                        bool     hash_key);
+
+void         pft_destroy(struct pft * table);
+
+void         pft_flush(struct pft * table);
+
+/* Passes ownership of the block of memory */
+int          pft_insert(struct pft * pft,
+                        uint64_t     dst,
+                        int *        fds,
+                        size_t       len);
+
+/* The block of memory returned is no copy */
+int          pft_lookup(struct pft * pft,
+                        uint64_t     dst,
+                        int **       fds,
+                        size_t *     len);
+
+int          pft_delete(struct pft * pft,
+                        uint64_t     dst);
+
+#endif /* OUROBOROS_PFT_H */
diff --git a/src/ipcpd/unicast/pff/simple.c b/src/ipcpd/unicast/pff/simple.c
new file mode 100644
index 00000000..a007bcec
--- /dev/null
+++ b/src/ipcpd/unicast/pff/simple.c
@@ -0,0 +1,190 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Simple PDU Forwarding Function
+ *
+ *    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/.
+ */
+
+#define _POSIX_C_SOURCE 200112L
+
+#include "config.h"
+
+#include <ouroboros/errno.h>
+
+#include "pft.h"
+#include "simple.h"
+
+#include <assert.h>
+#include <pthread.h>
+
+struct pff_i {
+        struct pft *     pft;
+        pthread_rwlock_t lock;
+};
+
+struct pff_ops simple_pff_ops = {
+        .create            = simple_pff_create,
+        .destroy           = simple_pff_destroy,
+        .lock              = simple_pff_lock,
+        .unlock            = simple_pff_unlock,
+        .add               = simple_pff_add,
+        .update            = simple_pff_update,
+        .del               = simple_pff_del,
+        .flush             = simple_pff_flush,
+        .nhop              = simple_pff_nhop,
+        .flow_state_change = NULL
+};
+
+struct pff_i * simple_pff_create(void)
+{
+        struct pff_i * tmp;
+
+        tmp = malloc(sizeof(*tmp));
+        if (tmp == NULL)
+                return NULL;
+
+        if (pthread_rwlock_init(&tmp->lock, NULL)) {
+                free(tmp);
+                return NULL;
+        }
+
+        tmp->pft = pft_create(PFT_SIZE, false);
+        if (tmp->pft == NULL) {
+                pthread_rwlock_destroy(&tmp->lock);
+                free(tmp);
+                return NULL;
+        }
+
+        return tmp;
+}
+
+void simple_pff_destroy(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_destroy(pff_i->pft);
+
+        pthread_rwlock_destroy(&pff_i->lock);
+        free(pff_i);
+}
+
+void simple_pff_lock(struct pff_i * pff_i)
+{
+        pthread_rwlock_wrlock(&pff_i->lock);
+}
+
+void simple_pff_unlock(struct pff_i * pff_i)
+{
+        pthread_rwlock_unlock(&pff_i->lock);
+}
+
+int simple_pff_add(struct pff_i * pff_i,
+                   uint64_t       addr,
+                   int *          fd,
+                   size_t         len)
+{
+        int * fds;
+
+        assert(pff_i);
+        assert(fd);
+        assert(len > 0);
+
+        (void) len;
+
+        fds = malloc(sizeof(*fds));
+        if (fds == NULL)
+                return -ENOMEM;
+
+        *fds = *fd;
+
+        if (pft_insert(pff_i->pft, addr, fds, 1)) {
+                free(fds);
+                return -1;
+        }
+
+        return 0;
+}
+
+int simple_pff_update(struct pff_i * pff_i,
+                      uint64_t       addr,
+                      int *          fd,
+                      size_t         len)
+{
+        int * fds;
+
+        assert(pff_i);
+        assert(fd);
+        assert(len > 0);
+
+        (void) len;
+
+        fds = malloc(sizeof(*fds));
+        if (fds == NULL)
+                return -ENOMEM;
+
+        *fds = *fd;
+
+        if (pft_delete(pff_i->pft, addr)) {
+                free(fds);
+                return -1;
+        }
+
+        if (pft_insert(pff_i->pft, addr, fds, 1)) {
+                free(fds);
+                return -1;
+        }
+
+        return 0;
+}
+
+int simple_pff_del(struct pff_i * pff_i,
+                   uint64_t       addr)
+{
+        assert(pff_i);
+
+        if (pft_delete(pff_i->pft, addr))
+                return -1;
+
+        return 0;
+}
+
+void simple_pff_flush(struct pff_i * pff_i)
+{
+        assert(pff_i);
+
+        pft_flush(pff_i->pft);
+}
+
+int simple_pff_nhop(struct pff_i * pff_i,
+                    uint64_t       addr)
+{
+        int *  fds;
+        size_t len;
+        int    fd = -1;
+
+        assert(pff_i);
+
+        pthread_rwlock_rdlock(&pff_i->lock);
+
+        if (pft_lookup(pff_i->pft, addr, &fds, &len) == 0)
+                fd = *fds;
+
+        pthread_rwlock_unlock(&pff_i->lock);
+
+        return fd;
+}
diff --git a/src/ipcpd/unicast/pff/simple.h b/src/ipcpd/unicast/pff/simple.h
new file mode 100644
index 00000000..e9083cf5
--- /dev/null
+++ b/src/ipcpd/unicast/pff/simple.h
@@ -0,0 +1,57 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Simple policy for PFF
+ *
+ *    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/.
+ */
+
+#ifndef OUROBOROS_IPCPD_UNICAST_SIMPLE_PFF_H
+#define OUROBOROS_IPCPD_UNICAST_SIMPLE_PFF_H
+
+#include "ops.h"
+
+struct pff_i * simple_pff_create(void);
+
+void           simple_pff_destroy(struct pff_i * pff_i);
+
+void           simple_pff_lock(struct pff_i * pff_i);
+
+void           simple_pff_unlock(struct pff_i * pff_i);
+
+int            simple_pff_add(struct pff_i * pff_i,
+                              uint64_t       addr,
+                              int *          fd,
+                              size_t         len);
+
+int            simple_pff_update(struct pff_i * pff_i,
+                                 uint64_t       addr,
+                                 int *          fd,
+                                 size_t         len);
+
+int            simple_pff_del(struct pff_i * pff_i,
+                              uint64_t       addr);
+
+void           simple_pff_flush(struct pff_i * pff_i);
+
+/* Returns fd towards next hop */
+int            simple_pff_nhop(struct pff_i * pff_i,
+                               uint64_t       addr);
+
+extern struct pff_ops simple_pff_ops;
+
+#endif /* OUROBOROS_IPCPD_UNICAST_SIMPLE_PFF_H */
diff --git a/src/ipcpd/unicast/pff/tests/CMakeLists.txt b/src/ipcpd/unicast/pff/tests/CMakeLists.txt
new file mode 100644
index 00000000..e7082372
--- /dev/null
+++ b/src/ipcpd/unicast/pff/tests/CMakeLists.txt
@@ -0,0 +1,34 @@
+get_filename_component(CURRENT_SOURCE_PARENT_DIR
+  ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
+get_filename_component(CURRENT_BINARY_PARENT_DIR
+  ${CMAKE_CURRENT_BINARY_DIR} DIRECTORY)
+
+include_directories(${CMAKE_CURRENT_SOURCE_DIR})
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+
+include_directories(${CURRENT_SOURCE_PARENT_DIR})
+include_directories(${CURRENT_BINARY_PARENT_DIR})
+
+include_directories(${CMAKE_SOURCE_DIR}/include)
+include_directories(${CMAKE_BINARY_DIR}/include)
+
+get_filename_component(PARENT_PATH ${CMAKE_CURRENT_SOURCE_DIR} DIRECTORY)
+get_filename_component(PARENT_DIR ${PARENT_PATH} NAME)
+
+create_test_sourcelist(${PARENT_DIR}_tests test_suite.c
+  # Add new tests here
+  pft_test.c
+  )
+
+add_executable(${PARENT_DIR}_test EXCLUDE_FROM_ALL ${${PARENT_DIR}_tests})
+target_link_libraries(${PARENT_DIR}_test ouroboros-common)
+
+add_dependencies(check ${PARENT_DIR}_test)
+
+set(tests_to_run ${${PARENT_DIR}_tests})
+remove(tests_to_run test_suite.c)
+
+foreach (test ${tests_to_run})
+  get_filename_component(test_name ${test} NAME_WE)
+  add_test(${test_name} ${C_TEST_PATH}/${PARENT_DIR}_test ${test_name})
+endforeach (test)
diff --git a/src/ipcpd/unicast/pff/tests/pft_test.c b/src/ipcpd/unicast/pff/tests/pft_test.c
new file mode 100644
index 00000000..c48267eb
--- /dev/null
+++ b/src/ipcpd/unicast/pff/tests/pft_test.c
@@ -0,0 +1,126 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Test of the hash table
+ *
+ *    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 "pft.c"
+
+#include <stdio.h>
+
+#define TBL_SIZE 256
+#define INT_TEST 4
+
+int pft_test(int     argc,
+             char ** argv)
+{
+        struct pft * pft;
+        int          i;
+        int *        j;
+        size_t       len;
+
+        (void) argc;
+        (void) argv;
+
+        pft = pft_create(TBL_SIZE, true);
+        if (pft == NULL) {
+                printf("Failed to create.\n");
+                return -1;
+        }
+
+        pft_destroy(pft);
+
+        pft = pft_create(TBL_SIZE, false);
+        if (pft == NULL) {
+                printf("Failed to create.\n");
+                return -1;
+        }
+
+        for (i = 0; i < TBL_SIZE + INT_TEST + 2; i++) {
+                j = malloc(sizeof(*j));
+                if (j == NULL) {
+                        printf("Failed to malloc.\n");
+                        pft_destroy(pft);
+                        return -1;
+                }
+                *j = i;
+
+                if (pft_insert(pft, i, j, 1)) {
+                        printf("Failed to insert.\n");
+                        pft_destroy(pft);
+                        free(j);
+                        return -1;
+                }
+        }
+
+        if (pft_lookup(pft, INT_TEST, &j, &len)) {
+                printf("Failed to lookup.\n");
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (*j != INT_TEST) {
+                printf("Lookup returned wrong value (%d != %d).\n",
+                       INT_TEST, *j);
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (pft_lookup(pft, TBL_SIZE + INT_TEST, &j, &len)) {
+                printf("Failed to lookup.\n");
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (*j != TBL_SIZE + INT_TEST) {
+                printf("Lookup returned wrong value (%d != %d).\n",
+                       INT_TEST, *j);
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (pft_delete(pft, INT_TEST)) {
+                printf("Failed to delete.\n");
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (pft_lookup(pft, INT_TEST, &j, &len) == 0) {
+                printf("Failed to delete properly.\n");
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (pft_lookup(pft, TBL_SIZE + INT_TEST, &j, &len)) {
+                printf("Failed to lookup after deletion.\n");
+                pft_destroy(pft);
+                return -1;
+        }
+
+        if (*j != TBL_SIZE + INT_TEST) {
+                printf("Lookup returned wrong value (%d != %d).\n",
+                       INT_TEST, *j);
+                pft_destroy(pft);
+                return -1;
+        }
+
+        pft_destroy(pft);
+
+        return 0;
+}