ipcpd: Rename hashtable to pft

This makes the hashtable more tailored to a packet forwarding table
(PFT). In the end not much of a change was needed, but now it's clear
the pft maps a destination address to a list of (outgoing) fds.

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

1 files changed, 222 insertions, 0 deletions

diff --git a/src/ipcpd/unicast/pol/pft.c b/src/ipcpd/unicast/pol/pft.c
new file mode 100644
index 00000000..924efbe1
--- /dev/null
+++ b/src/ipcpd/unicast/pol/pft.c
@@ -0,0 +1,222 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2020
+ *
+ * Packet forwarding table (PFT) with chaining on collisions
+ *
+ *    Dimitri Staessens <dimitri.staessens@ugent.be>
+ *    Sander Vrijders   <sander.vrijders@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/.
+ */
+
+#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);
+
+        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;
+}