Add equal-cost multipath routing policy

This adds an equal-cost multipath routing policy to Ouroboros, based
on Nick Aerts' code. When selected, flows will send packets over all
paths with equal cost (hop count). Path selection is round-robin. It
does not yet take into account flows that are down.

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

1 files changed, 198 insertions, 0 deletions

diff --git a/src/ipcpd/unicast/pol/multipath_pff.c b/src/ipcpd/unicast/pol/multipath_pff.c
new file mode 100644
index 00000000..8f619006
--- /dev/null
+++ b/src/ipcpd/unicast/pol/multipath_pff.c
@@ -0,0 +1,198 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2020
+ *
+ * Policy for PFF supporting multipath routing
+ *
+ *    Dimitri Staessens <dimitri.staessens@ugent.be>
+ *    Sander Vrijders   <sander.vrijders@ugent.be>
+ *    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_pff.h"
+
+#include <string.h>
+#include <assert.h>
+#include <pthread.h>
+
+struct pff_i {
+        struct pft *     pft;
+        pthread_rwlock_t lock;
+};
+
+struct pol_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 (fds == 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, fds, 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;
+}