babeld: Initial import, for Babel routing protocol.

* Initial import of the Babel routing protocol, ported to Quagga.
* LICENCE: Update the original LICENCE file to include all known potentially
  applicable copyright claims.  Ask that any future contributors to babeld/
  grant MIT/X11 licence to their work.
* *.{c,h}: Add GPL headers, in according with the SFLC guidance on
  dealing with potentially mixed GPL/other licensed work, at:

  https://www.softwarefreedom.org/resources/2007/gpl-non-gpl-collaboration.html

1 files changed, 1456 insertions, 0 deletions

diff --git a/babeld/message.c b/babeld/message.c
new file mode 100644
index 00000000..bfb17625
--- /dev/null
+++ b/babeld/message.c
@@ -0,0 +1,1456 @@
+/*  
+ *  This file is free software: you may copy, redistribute and/or modify it  
+ *  under the terms of the GNU General Public License as published by the  
+ *  Free Software Foundation, either version 2 of the License, or (at your  
+ *  option) any later version.  
+ *  
+ *  This file 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, see <http://www.gnu.org/licenses/>.  
+ *  
+ * This file incorporates work covered by the following copyright and  
+ * permission notice:  
+ *  
+
+Copyright (c) 2007, 2008 by Juliusz Chroboczek
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <assert.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <zebra.h>
+#include "if.h"
+
+#include "babeld.h"
+#include "util.h"
+#include "net.h"
+#include "babel_interface.h"
+#include "source.h"
+#include "neighbour.h"
+#include "route.h"
+#include "xroute.h"
+#include "resend.h"
+#include "message.h"
+#include "kernel.h"
+
+unsigned char packet_header[4] = {42, 2};
+
+int parasitic = 0;
+int split_horizon = 1;
+
+unsigned short myseqno = 0;
+struct timeval seqno_time = {0, 0};
+
+#define UNICAST_BUFSIZE 1024
+int unicast_buffered = 0;
+unsigned char *unicast_buffer = NULL;
+struct neighbour *unicast_neighbour = NULL;
+struct timeval unicast_flush_timeout = {0, 0};
+
+static const unsigned char v4prefix[16] =
+    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
+
+static int
+network_prefix(int ae, int plen, unsigned int omitted,
+               const unsigned char *p, const unsigned char *dp,
+               unsigned int len, unsigned char *p_r)
+{
+    unsigned pb;
+    unsigned char prefix[16];
+
+    if(plen >= 0)
+        pb = (plen + 7) / 8;
+    else if(ae == 1)
+        pb = 4;
+    else
+        pb = 16;
+
+    if(pb > 16)
+        return -1;
+
+    memset(prefix, 0, 16);
+
+    switch(ae) {
+    case 0: break;
+    case 1:
+        if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
+            return -1;
+        memcpy(prefix, v4prefix, 12);
+        if(omitted) {
+            if (dp == NULL || !v4mapped(dp)) return -1;
+            memcpy(prefix, dp, 12 + omitted);
+        }
+        if(pb > omitted) memcpy(prefix + 12 + omitted, p, pb - omitted);
+        break;
+    case 2:
+        if(omitted > 16 || (pb > omitted && len < pb - omitted)) return -1;
+        if(omitted) {
+            if (dp == NULL || v4mapped(dp)) return -1;
+            memcpy(prefix, dp, omitted);
+        }
+        if(pb > omitted) memcpy(prefix + omitted, p, pb - omitted);
+        break;
+    case 3:
+        if(pb > 8 && len < pb - 8) return -1;
+        prefix[0] = 0xfe;
+        prefix[1] = 0x80;
+        if(pb > 8) memcpy(prefix + 8, p, pb - 8);
+        break;
+    default:
+        return -1;
+    }
+
+    mask_prefix(p_r, prefix, plen < 0 ? 128 : ae == 1 ? plen + 96 : plen);
+    return 1;
+}
+
+static int
+network_address(int ae, const unsigned char *a, unsigned int len,
+                unsigned char *a_r)
+{
+    return network_prefix(ae, -1, 0, a, NULL, len, a_r);
+}
+
+void
+parse_packet(const unsigned char *from, struct interface *ifp,
+             const unsigned char *packet, int packetlen)
+{
+    int i;
+    const unsigned char *message;
+    unsigned char type, len;
+    int bodylen;
+    struct neighbour *neigh;
+    int have_router_id = 0, have_v4_prefix = 0, have_v6_prefix = 0,
+        have_v4_nh = 0, have_v6_nh = 0;
+    unsigned char router_id[8], v4_prefix[16], v6_prefix[16],
+        v4_nh[16], v6_nh[16];
+
+    if(!linklocal(from)) {
+        fprintf(stderr, "Received packet from non-local address %s.\n",
+                format_address(from));
+        return;
+    }
+
+    if(packet[0] != 42) {
+        fprintf(stderr, "Received malformed packet on %s from %s.\n",
+                ifp->name, format_address(from));
+        return;
+    }
+
+    if(packet[1] != 2) {
+        fprintf(stderr,
+                "Received packet with unknown version %d on %s from %s.\n",
+                packet[1], ifp->name, format_address(from));
+        return;
+    }
+
+    neigh = find_neighbour(from, ifp);
+    if(neigh == NULL) {
+        fprintf(stderr, "Couldn't allocate neighbour.\n");
+        return;
+    }
+
+    DO_NTOHS(bodylen, packet + 2);
+
+    if(bodylen + 4 > packetlen) {
+        fprintf(stderr, "Received truncated packet (%d + 4 > %d).\n",
+                bodylen, packetlen);
+        bodylen = packetlen - 4;
+    }
+
+    i = 0;
+    while(i < bodylen) {
+        message = packet + 4 + i;
+        type = message[0];
+        if(type == MESSAGE_PAD1) {
+            debugf(BABEL_DEBUG_COMMON,"Received pad1 from %s on %s.",
+                   format_address(from), ifp->name);
+            i++;
+            continue;
+        }
+        if(i + 1 > bodylen) {
+            fprintf(stderr, "Received truncated message.\n");
+            break;
+        }
+        len = message[1];
+        if(i + len > bodylen) {
+            fprintf(stderr, "Received truncated message.\n");
+            break;
+        }
+
+        if(type == MESSAGE_PADN) {
+            debugf(BABEL_DEBUG_COMMON,"Received pad%d from %s on %s.",
+                   len, format_address(from), ifp->name);
+        } else if(type == MESSAGE_ACK_REQ) {
+            unsigned short nonce, interval;
+            if(len < 6) goto fail;
+            DO_NTOHS(nonce, message + 4);
+            DO_NTOHS(interval, message + 6);
+            debugf(BABEL_DEBUG_COMMON,"Received ack-req (%04X %d) from %s on %s.",
+                   nonce, interval, format_address(from), ifp->name);
+            send_ack(neigh, nonce, interval);
+        } else if(type == MESSAGE_ACK) {
+            debugf(BABEL_DEBUG_COMMON,"Received ack from %s on %s.",
+                   format_address(from), ifp->name);
+            /* Nothing right now */
+        } else if(type == MESSAGE_HELLO) {
+            unsigned short seqno, interval;
+            int changed;
+            if(len < 6) goto fail;
+            DO_NTOHS(seqno, message + 4);
+            DO_NTOHS(interval, message + 6);
+            debugf(BABEL_DEBUG_COMMON,"Received hello %d (%d) from %s on %s.",
+                   seqno, interval,
+                   format_address(from), ifp->name);
+            babel_get_if_nfo(ifp)->activity_time = babel_now.tv_sec;
+            changed = update_neighbour(neigh, seqno, interval);
+            update_neighbour_metric(neigh, changed);
+            if(interval > 0)
+                schedule_neighbours_check(interval * 10, 0);
+        } else if(type == MESSAGE_IHU) {
+            unsigned short txcost, interval;
+            unsigned char address[16];
+            int rc;
+            if(len < 6) goto fail;
+            DO_NTOHS(txcost, message + 4);
+            DO_NTOHS(interval, message + 6);
+            rc = network_address(message[2], message + 8, len - 6, address);
+            if(rc < 0) goto fail;
+            debugf(BABEL_DEBUG_COMMON,"Received ihu %d (%d) from %s on %s for %s.",
+                   txcost, interval,
+                   format_address(from), ifp->name,
+                   format_address(address));
+            if(message[2] == 0 || is_interface_ll_address(ifp, address)) {
+                int changed = txcost != neigh->txcost;
+                neigh->txcost = txcost;
+                neigh->ihu_time = babel_now;
+                neigh->ihu_interval = interval;
+                update_neighbour_metric(neigh, changed);
+                if(interval > 0)
+                    schedule_neighbours_check(interval * 10 * 3, 0);
+            }
+        } else if(type == MESSAGE_ROUTER_ID) {
+            if(len < 10) {
+                have_router_id = 0;
+                goto fail;
+            }
+            memcpy(router_id, message + 4, 8);
+            have_router_id = 1;
+            debugf(BABEL_DEBUG_COMMON,"Received router-id %s from %s on %s.",
+                   format_eui64(router_id), format_address(from), ifp->name);
+        } else if(type == MESSAGE_NH) {
+            unsigned char nh[16];
+            int rc;
+            if(len < 2) {
+                have_v4_nh = 0;
+                have_v6_nh = 0;
+                goto fail;
+            }
+            rc = network_address(message[2], message + 4, len - 2,
+                                 nh);
+            if(rc < 0) {
+                have_v4_nh = 0;
+                have_v6_nh = 0;
+                goto fail;
+            }
+            debugf(BABEL_DEBUG_COMMON,"Received nh %s (%d) from %s on %s.",
+                   format_address(nh), message[2],
+                   format_address(from), ifp->name);
+            if(message[2] == 1) {
+                memcpy(v4_nh, nh, 16);
+                have_v4_nh = 1;
+            } else {
+                memcpy(v6_nh, nh, 16);
+                have_v6_nh = 1;
+            }
+        } else if(type == MESSAGE_UPDATE) {
+            unsigned char prefix[16], *nh;
+            unsigned char plen;
+            unsigned short interval, seqno, metric;
+            int rc;
+            if(len < 10) {
+                if(len < 2 || message[3] & 0x80)
+                    have_v4_prefix = have_v6_prefix = 0;
+                goto fail;
+            }
+            DO_NTOHS(interval, message + 6);
+            DO_NTOHS(seqno, message + 8);
+            DO_NTOHS(metric, message + 10);
+            if(message[5] == 0 ||
+               (message[3] == 1 ? have_v4_prefix : have_v6_prefix))
+                rc = network_prefix(message[2], message[4], message[5],
+                                    message + 12,
+                                    message[2] == 1 ? v4_prefix : v6_prefix,
+                                    len - 10, prefix);
+            else
+                rc = -1;
+            if(rc < 0) {
+                if(message[3] & 0x80)
+                    have_v4_prefix = have_v6_prefix = 0;
+                goto fail;
+            }
+
+            plen = message[4] + (message[2] == 1 ? 96 : 0);
+
+            if(message[3] & 0x80) {
+                if(message[2] == 1) {
+                    memcpy(v4_prefix, prefix, 16);
+                    have_v4_prefix = 1;
+                } else {
+                    memcpy(v6_prefix, prefix, 16);
+                    have_v6_prefix = 1;
+                }
+            }
+            if(message[3] & 0x40) {
+                if(message[2] == 1) {
+                    memset(router_id, 0, 4);
+                    memcpy(router_id + 4, prefix + 12, 4);
+                } else {
+                    memcpy(router_id, prefix + 8, 8);
+                }
+                have_router_id = 1;
+            }
+            if(!have_router_id && message[2] != 0) {
+                fprintf(stderr, "Received prefix with no router id.\n");
+                goto fail;
+            }
+            debugf(BABEL_DEBUG_COMMON,"Received update%s%s for %s from %s on %s.",
+                   (message[3] & 0x80) ? "/prefix" : "",
+                   (message[3] & 0x40) ? "/id" : "",
+                   format_prefix(prefix, plen),
+                   format_address(from), ifp->name);
+
+            if(message[2] == 0) {
+                if(metric < 0xFFFF) {
+                    fprintf(stderr,
+                            "Received wildcard update with finite metric.\n");
+                    goto done;
+                }
+                retract_neighbour_routes(neigh);
+                goto done;
+            } else if(message[2] == 1) {
+                if(!have_v4_nh)
+                    goto fail;
+                nh = v4_nh;
+            } else if(have_v6_nh) {
+                nh = v6_nh;
+            } else {
+                nh = neigh->address;
+            }
+
+            if(message[2] == 1) {
+                if(!babel_get_if_nfo(ifp)->ipv4)
+                    goto done;
+            }
+
+            update_route(router_id, prefix, plen, seqno, metric, interval,
+                         neigh, nh);
+        } else if(type == MESSAGE_REQUEST) {
+            unsigned char prefix[16], plen;
+            int rc;
+            if(len < 2) goto fail;
+            rc = network_prefix(message[2], message[3], 0,
+                                message + 4, NULL, len - 2, prefix);
+            if(rc < 0) goto fail;
+            plen = message[3] + (message[2] == 1 ? 96 : 0);
+            debugf(BABEL_DEBUG_COMMON,"Received request for %s from %s on %s.",
+                   message[2] == 0 ? "any" : format_prefix(prefix, plen),
+                   format_address(from), ifp->name);
+            if(message[2] == 0) {
+                /* If a neighbour is requesting a full route dump from us,
+                   we might as well send it an IHU. */
+                send_ihu(neigh, NULL);
+                send_update(neigh->ifp, 0, NULL, 0);
+            } else {
+                send_update(neigh->ifp, 0, prefix, plen);
+            }
+        } else if(type == MESSAGE_MH_REQUEST) {
+            unsigned char prefix[16], plen;
+            unsigned short seqno;
+            int rc;
+            if(len < 14) goto fail;
+            DO_NTOHS(seqno, message + 4);
+            rc = network_prefix(message[2], message[3], 0,
+                                message + 16, NULL, len - 14, prefix);
+            if(rc < 0) goto fail;
+            plen = message[3] + (message[2] == 1 ? 96 : 0);
+            debugf(BABEL_DEBUG_COMMON,"Received request (%d) for %s from %s on %s (%s, %d).",
+                   message[6],
+                   format_prefix(prefix, plen),
+                   format_address(from), ifp->name,
+                   format_eui64(message + 8), seqno);
+            handle_request(neigh, prefix, plen, message[6],
+                           seqno, message + 8);
+        } else {
+            debugf(BABEL_DEBUG_COMMON,"Received unknown packet type %d from %s on %s.",
+                   type, format_address(from), ifp->name);
+        }
+    done:
+        i += len + 2;
+        continue;
+
+    fail:
+        fprintf(stderr, "Couldn't parse packet (%d, %d) from %s on %s.\n",
+                message[0], message[1], format_address(from), ifp->name);
+        goto done;
+    }
+    return;
+}
+
+/* Under normal circumstances, there are enough moderation mechanisms
+   elsewhere in the protocol to make sure that this last-ditch check
+   should never trigger.  But I'm superstitious. */
+
+static int
+check_bucket(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    if(babel_ifp->bucket <= 0) {
+        int seconds = babel_now.tv_sec - babel_ifp->bucket_time;
+        if(seconds > 0) {
+            babel_ifp->bucket = MIN(BUCKET_TOKENS_MAX,
+                              seconds * BUCKET_TOKENS_PER_SEC);
+        }
+        /* Reset bucket time unconditionally, in case clock is stepped. */
+        babel_ifp->bucket_time = babel_now.tv_sec;
+    }
+
+    if(babel_ifp->bucket > 0) {
+        babel_ifp->bucket--;
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+void
+flushbuf(struct interface *ifp)
+{
+    int rc;
+    struct sockaddr_in6 sin6;
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+
+    assert(babel_ifp->buffered <= babel_ifp->bufsize);
+
+    flushupdates(ifp);
+
+    if(babel_ifp->buffered > 0) {
+        debugf(BABEL_DEBUG_COMMON,"  (flushing %d buffered bytes on %s)",
+               babel_ifp->buffered, ifp->name);
+        if(check_bucket(ifp)) {
+            memset(&sin6, 0, sizeof(sin6));
+            sin6.sin6_family = AF_INET6;
+            memcpy(&sin6.sin6_addr, protocol_group, 16);
+            sin6.sin6_port = htons(protocol_port);
+            sin6.sin6_scope_id = ifp->ifindex;
+            DO_HTONS(packet_header + 2, babel_ifp->buffered);
+            rc = babel_send(protocol_socket,
+                            packet_header, sizeof(packet_header),
+                            babel_ifp->sendbuf, babel_ifp->buffered,
+                            (struct sockaddr*)&sin6, sizeof(sin6));
+            if(rc < 0)
+                zlog_err("send: %s", safe_strerror(errno));
+        } else {
+            fprintf(stderr, "Warning: bucket full, dropping packet to %s.\n",
+                    ifp->name);
+        }
+    }
+    VALGRIND_MAKE_MEM_UNDEFINED(babel_ifp->sendbuf, babel_ifp->bufsize);
+    babel_ifp->buffered = 0;
+    babel_ifp->have_buffered_hello = 0;
+    babel_ifp->have_buffered_id = 0;
+    babel_ifp->have_buffered_nh = 0;
+    babel_ifp->have_buffered_prefix = 0;
+    babel_ifp->flush_timeout.tv_sec = 0;
+    babel_ifp->flush_timeout.tv_usec = 0;
+}
+
+static void
+schedule_flush(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    unsigned msecs = jitter(babel_ifp, 0);
+    if(babel_ifp->flush_timeout.tv_sec != 0 &&
+       timeval_minus_msec(&babel_ifp->flush_timeout, &babel_now) < msecs)
+        return;
+    set_timeout(&babel_ifp->flush_timeout, msecs);
+}
+
+static void
+schedule_flush_now(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    /* Almost now */
+    unsigned msecs = roughly(10);
+    if(babel_ifp->flush_timeout.tv_sec != 0 &&
+       timeval_minus_msec(&babel_ifp->flush_timeout, &babel_now) < msecs)
+        return;
+    set_timeout(&babel_ifp->flush_timeout, msecs);
+}
+
+static void
+schedule_unicast_flush(unsigned msecs)
+{
+    if(!unicast_neighbour)
+        return;
+    if(unicast_flush_timeout.tv_sec != 0 &&
+       timeval_minus_msec(&unicast_flush_timeout, &babel_now) < msecs)
+        return;
+    unicast_flush_timeout.tv_usec = (babel_now.tv_usec + msecs * 1000) %1000000;
+    unicast_flush_timeout.tv_sec =
+        babel_now.tv_sec + (babel_now.tv_usec / 1000 + msecs) / 1000;
+}
+
+static void
+ensure_space(struct interface *ifp, int space)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    if(babel_ifp->bufsize - babel_ifp->buffered < space)
+        flushbuf(ifp);
+}
+
+static void
+start_message(struct interface *ifp, int type, int len)
+{
+  babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    if(babel_ifp->bufsize - babel_ifp->buffered < len + 2)
+        flushbuf(ifp);
+    babel_ifp->sendbuf[babel_ifp->buffered++] = type;
+    babel_ifp->sendbuf[babel_ifp->buffered++] = len;
+}
+
+static void
+end_message(struct interface *ifp, int type, int bytes)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    assert(babel_ifp->buffered >= bytes + 2 &&
+           babel_ifp->sendbuf[babel_ifp->buffered - bytes - 2] == type &&
+           babel_ifp->sendbuf[babel_ifp->buffered - bytes - 1] == bytes);
+    schedule_flush(ifp);
+}
+
+static void
+accumulate_byte(struct interface *ifp, unsigned char value)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    babel_ifp->sendbuf[babel_ifp->buffered++] = value;
+}
+
+static void
+accumulate_short(struct interface *ifp, unsigned short value)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    DO_HTONS(babel_ifp->sendbuf + babel_ifp->buffered, value);
+    babel_ifp->buffered += 2;
+}
+
+static void
+accumulate_bytes(struct interface *ifp,
+                 const unsigned char *value, unsigned len)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    memcpy(babel_ifp->sendbuf + babel_ifp->buffered, value, len);
+    babel_ifp->buffered += len;
+}
+
+static int
+start_unicast_message(struct neighbour *neigh, int type, int len)
+{
+    if(unicast_neighbour) {
+        if(neigh != unicast_neighbour ||
+           unicast_buffered + len + 2 >=
+           MIN(UNICAST_BUFSIZE, babel_get_if_nfo(neigh->ifp)->bufsize))
+            flush_unicast(0);
+    }
+    if(!unicast_buffer)
+        unicast_buffer = malloc(UNICAST_BUFSIZE);
+    if(!unicast_buffer) {
+        zlog_err("malloc(unicast_buffer): %s", safe_strerror(errno));
+        return -1;
+    }
+
+    unicast_neighbour = neigh;
+
+    unicast_buffer[unicast_buffered++] = type;
+    unicast_buffer[unicast_buffered++] = len;
+    return 1;
+}
+
+static void
+end_unicast_message(struct neighbour *neigh, int type, int bytes)
+{
+    assert(unicast_neighbour == neigh && unicast_buffered >= bytes + 2 &&
+           unicast_buffer[unicast_buffered - bytes - 2] == type &&
+           unicast_buffer[unicast_buffered - bytes - 1] == bytes);
+    schedule_unicast_flush(jitter(babel_get_if_nfo(neigh->ifp), 0));
+}
+
+static void
+accumulate_unicast_byte(struct neighbour *neigh, unsigned char value)
+{
+    unicast_buffer[unicast_buffered++] = value;
+}
+
+static void
+accumulate_unicast_short(struct neighbour *neigh, unsigned short value)
+{
+    DO_HTONS(unicast_buffer + unicast_buffered, value);
+    unicast_buffered += 2;
+}
+
+static void
+accumulate_unicast_bytes(struct neighbour *neigh,
+                         const unsigned char *value, unsigned len)
+{
+    memcpy(unicast_buffer + unicast_buffered, value, len);
+    unicast_buffered += len;
+}
+
+void
+send_ack(struct neighbour *neigh, unsigned short nonce, unsigned short interval)
+{
+    int rc;
+    debugf(BABEL_DEBUG_COMMON,"Sending ack (%04x) to %s on %s.",
+           nonce, format_address(neigh->address), neigh->ifp->name);
+    rc = start_unicast_message(neigh, MESSAGE_ACK, 2); if(rc < 0) return;
+    accumulate_unicast_short(neigh, nonce);
+    end_unicast_message(neigh, MESSAGE_ACK, 2);
+    /* Roughly yields a value no larger than 3/2, so this meets the deadline */
+    schedule_unicast_flush(roughly(interval * 6));
+}
+
+void
+send_hello_noupdate(struct interface *ifp, unsigned interval)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    /* This avoids sending multiple hellos in a single packet, which breaks
+       link quality estimation. */
+    if(babel_ifp->have_buffered_hello)
+        flushbuf(ifp);
+
+    babel_ifp->hello_seqno = seqno_plus(babel_ifp->hello_seqno, 1);
+    set_timeout(&babel_ifp->hello_timeout, babel_ifp->hello_interval);
+
+    if(!if_up(ifp))
+        return;
+
+    debugf(BABEL_DEBUG_COMMON,"Sending hello %d (%d) to %s.",
+           babel_ifp->hello_seqno, interval, ifp->name);
+
+    start_message(ifp, MESSAGE_HELLO, 6);
+    accumulate_short(ifp, 0);
+    accumulate_short(ifp, babel_ifp->hello_seqno);
+    accumulate_short(ifp, interval > 0xFFFF ? 0xFFFF : interval);
+    end_message(ifp, MESSAGE_HELLO, 6);
+    babel_ifp->have_buffered_hello = 1;
+}
+
+void
+send_hello(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    send_hello_noupdate(ifp, (babel_ifp->hello_interval + 9) / 10);
+    /* Send full IHU every 3 hellos, and marginal IHU each time */
+    if(babel_ifp->hello_seqno % 3 == 0)
+        send_ihu(NULL, ifp);
+    else
+        send_marginal_ihu(ifp);
+}
+
+void
+flush_unicast(int dofree)
+{
+    struct sockaddr_in6 sin6;
+    int rc;
+
+    if(unicast_buffered == 0)
+        goto done;
+
+    if(!if_up(unicast_neighbour->ifp))
+        goto done;
+
+    /* Preserve ordering of messages */
+    flushbuf(unicast_neighbour->ifp);
+
+    if(check_bucket(unicast_neighbour->ifp)) {
+        memset(&sin6, 0, sizeof(sin6));
+        sin6.sin6_family = AF_INET6;
+        memcpy(&sin6.sin6_addr, unicast_neighbour->address, 16);
+        sin6.sin6_port = htons(protocol_port);
+        sin6.sin6_scope_id = unicast_neighbour->ifp->ifindex;
+        DO_HTONS(packet_header + 2, unicast_buffered);
+        rc = babel_send(protocol_socket,
+                        packet_header, sizeof(packet_header),
+                        unicast_buffer, unicast_buffered,
+                        (struct sockaddr*)&sin6, sizeof(sin6));
+        if(rc < 0)
+            zlog_err("send(unicast): %s", safe_strerror(errno));
+    } else {
+        fprintf(stderr,
+                "Warning: bucket full, dropping unicast packet"
+                "to %s if %s.\n",
+                format_address(unicast_neighbour->address),
+                unicast_neighbour->ifp->name);
+    }
+
+ done:
+    VALGRIND_MAKE_MEM_UNDEFINED(unicast_buffer, UNICAST_BUFSIZE);
+    unicast_buffered = 0;
+    if(dofree && unicast_buffer) {
+        free(unicast_buffer);
+        unicast_buffer = NULL;
+    }
+    unicast_neighbour = NULL;
+    unicast_flush_timeout.tv_sec = 0;
+    unicast_flush_timeout.tv_usec = 0;
+}
+
+static void
+really_send_update(struct interface *ifp,
+                   const unsigned char *id,
+                   const unsigned char *prefix, unsigned char plen,
+                   unsigned short seqno, unsigned short metric)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    int add_metric, v4, real_plen, omit = 0;
+    const unsigned char *real_prefix;
+    unsigned short flags = 0;
+
+    if(!if_up(ifp))
+        return;
+
+    add_metric = output_filter(id, prefix, plen, ifp->ifindex);
+    if(add_metric >= INFINITY)
+        return;
+
+    metric = MIN(metric + add_metric, INFINITY);
+    /* Worst case */
+    ensure_space(ifp, 20 + 12 + 28);
+
+    v4 = plen >= 96 && v4mapped(prefix);
+
+    if(v4) {
+        if(!babel_ifp->ipv4)
+            return;
+        if(!babel_ifp->have_buffered_nh ||
+           memcmp(babel_ifp->buffered_nh, babel_ifp->ipv4, 4) != 0) {
+            start_message(ifp, MESSAGE_NH, 6);
+            accumulate_byte(ifp, 1);
+            accumulate_byte(ifp, 0);
+            accumulate_bytes(ifp, babel_ifp->ipv4, 4);
+            end_message(ifp, MESSAGE_NH, 6);
+            memcpy(babel_ifp->buffered_nh, babel_ifp->ipv4, 4);
+            babel_ifp->have_buffered_nh = 1;
+        }
+
+        real_prefix = prefix + 12;
+        real_plen = plen - 96;
+    } else {
+        if(babel_ifp->have_buffered_prefix) {
+            while(omit < plen / 8 &&
+                  babel_ifp->buffered_prefix[omit] == prefix[omit])
+                omit++;
+        }
+        if(!babel_ifp->have_buffered_prefix || plen >= 48)
+            flags |= 0x80;
+        real_prefix = prefix;
+        real_plen = plen;
+    }
+
+    if(!babel_ifp->have_buffered_id
+       || memcmp(id, babel_ifp->buffered_id, 8) != 0) {
+        if(real_plen == 128 && memcmp(real_prefix + 8, id, 8) == 0) {
+            flags |= 0x40;
+        } else {
+            start_message(ifp, MESSAGE_ROUTER_ID, 10);
+            accumulate_short(ifp, 0);
+            accumulate_bytes(ifp, id, 8);
+            end_message(ifp, MESSAGE_ROUTER_ID, 10);
+        }
+        memcpy(babel_ifp->buffered_id, id, 16);
+        babel_ifp->have_buffered_id = 1;
+    }
+
+    start_message(ifp, MESSAGE_UPDATE, 10 + (real_plen + 7) / 8 - omit);
+    accumulate_byte(ifp, v4 ? 1 : 2);
+    accumulate_byte(ifp, flags);
+    accumulate_byte(ifp, real_plen);
+    accumulate_byte(ifp, omit);
+    accumulate_short(ifp, (babel_ifp->update_interval + 5) / 10);
+    accumulate_short(ifp, seqno);
+    accumulate_short(ifp, metric);
+    accumulate_bytes(ifp, real_prefix + omit, (real_plen + 7) / 8 - omit);
+    end_message(ifp, MESSAGE_UPDATE, 10 + (real_plen + 7) / 8 - omit);
+
+    if(flags & 0x80) {
+        memcpy(babel_ifp->buffered_prefix, prefix, 16);
+        babel_ifp->have_buffered_prefix = 1;
+    }
+}
+
+static int
+compare_buffered_updates(const void *av, const void *bv)
+{
+    const struct buffered_update *a = av, *b = bv;
+    int rc, v4a, v4b, ma, mb;
+
+    rc = memcmp(a->id, b->id, 8);
+    if(rc != 0)
+        return rc;
+
+    v4a = (a->plen >= 96 && v4mapped(a->prefix));
+    v4b = (b->plen >= 96 && v4mapped(b->prefix));
+
+    if(v4a > v4b)
+        return 1;
+    else if(v4a < v4b)
+        return -1;
+
+    ma = (!v4a && a->plen == 128 && memcmp(a->prefix + 8, a->id, 8) == 0);
+    mb = (!v4b && b->plen == 128 && memcmp(b->prefix + 8, b->id, 8) == 0);
+
+    if(ma > mb)
+        return -1;
+    else if(mb > ma)
+        return 1;
+
+    if(a->plen < b->plen)
+        return 1;
+    else if(a->plen > b->plen)
+        return -1;
+
+    return memcmp(a->prefix, b->prefix, 16);
+}
+
+void
+flushupdates(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    struct xroute *xroute;
+    struct route *route;
+    const unsigned char *last_prefix = NULL;
+    unsigned char last_plen = 0xFF;
+    int i;
+
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node)
+            flushupdates(ifp_aux);
+        return;
+    }
+
+    babel_ifp = babel_get_if_nfo(ifp);
+    if(babel_ifp->num_buffered_updates > 0) {
+        struct buffered_update *b = babel_ifp->buffered_updates;
+        int n = babel_ifp->num_buffered_updates;
+
+        babel_ifp->buffered_updates = NULL;
+        babel_ifp->update_bufsize = 0;
+        babel_ifp->num_buffered_updates = 0;
+
+        if(!if_up(ifp))
+            goto done;
+
+        debugf(BABEL_DEBUG_COMMON,"  (flushing %d buffered updates on %s (%d))",
+               n, ifp->name, ifp->ifindex);
+
+        /* In order to send fewer update messages, we want to send updates
+           with the same router-id together, with IPv6 going out before IPv4. */
+
+        for(i = 0; i < n; i++) {
+            route = find_installed_route(b[i].prefix, b[i].plen);
+            if(route)
+                memcpy(b[i].id, route->src->id, 8);
+            else
+                memcpy(b[i].id, myid, 8);
+        }
+
+        qsort(b, n, sizeof(struct buffered_update), compare_buffered_updates);
+
+        for(i = 0; i < n; i++) {
+            unsigned short seqno;
+            unsigned short metric;
+
+            /* The same update may be scheduled multiple times before it is
+               sent out.  Since our buffer is now sorted, it is enough to
+               compare with the previous update. */
+
+            if(last_prefix) {
+                if(b[i].plen == last_plen &&
+                   memcmp(b[i].prefix, last_prefix, 16) == 0)
+                    continue;
+            }
+
+            xroute = find_xroute(b[i].prefix, b[i].plen);
+            route = find_installed_route(b[i].prefix, b[i].plen);
+
+            if(xroute && (!route || xroute->metric <= kernel_metric)) {
+                really_send_update(ifp, myid,
+                                   xroute->prefix, xroute->plen,
+                                   myseqno, xroute->metric);
+                last_prefix = xroute->prefix;
+                last_plen = xroute->plen;
+            } else if(route) {
+                seqno = route->seqno;
+                metric = route_metric(route);
+                if(metric < INFINITY)
+                    satisfy_request(route->src->prefix, route->src->plen,
+                                    seqno, route->src->id, ifp);
+                if((babel_ifp->flags & BABEL_IF_SPLIT_HORIZON) &&
+                   route->neigh->ifp == ifp)
+                    continue;
+                really_send_update(ifp, route->src->id,
+                                   route->src->prefix,
+                                   route->src->plen,
+                                   seqno, metric);
+                update_source(route->src, seqno, metric);
+                last_prefix = route->src->prefix;
+                last_plen = route->src->plen;
+            } else {
+            /* There's no route for this prefix.  This can happen shortly
+               after an xroute has been retracted, so send a retraction. */
+                really_send_update(ifp, myid, b[i].prefix, b[i].plen,
+                                   myseqno, INFINITY);
+            }
+        }
+        schedule_flush_now(ifp);
+    done:
+        free(b);
+    }
+    babel_ifp->update_flush_timeout.tv_sec = 0;
+    babel_ifp->update_flush_timeout.tv_usec = 0;
+}
+
+static void
+schedule_update_flush(struct interface *ifp, int urgent)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    unsigned msecs;
+    msecs = update_jitter(babel_ifp, urgent);
+    if(babel_ifp->update_flush_timeout.tv_sec != 0 &&
+       timeval_minus_msec(&babel_ifp->update_flush_timeout, &babel_now) < msecs)
+        return;
+    set_timeout(&babel_ifp->update_flush_timeout, msecs);
+}
+
+static void
+buffer_update(struct interface *ifp,
+              const unsigned char *prefix, unsigned char plen)
+{
+    babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
+    if(babel_ifp->num_buffered_updates > 0 &&
+       babel_ifp->num_buffered_updates >= babel_ifp->update_bufsize)
+        flushupdates(ifp);
+
+    if(babel_ifp->update_bufsize == 0) {
+        int n;
+        assert(babel_ifp->buffered_updates == NULL);
+        n = MAX(babel_ifp->bufsize / 16, 4);
+    again:
+        babel_ifp->buffered_updates = malloc(n *sizeof(struct buffered_update));
+        if(babel_ifp->buffered_updates == NULL) {
+            zlog_err("malloc(buffered_updates): %s", safe_strerror(errno));
+            if(n > 4) {
+                n = 4;
+                goto again;
+            }
+            return;
+        }
+        babel_ifp->update_bufsize = n;
+        babel_ifp->num_buffered_updates = 0;
+    }
+
+    memcpy(babel_ifp->buffered_updates[babel_ifp->num_buffered_updates].prefix,
+           prefix, 16);
+    babel_ifp->buffered_updates[babel_ifp->num_buffered_updates].plen = plen;
+    babel_ifp->num_buffered_updates++;
+}
+
+void
+send_update(struct interface *ifp, int urgent,
+            const unsigned char *prefix, unsigned char plen)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    int i;
+
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        struct route *route;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node)
+            send_update(ifp_aux, urgent, prefix, plen);
+        if(prefix) {
+            /* Since flushupdates only deals with non-wildcard interfaces, we
+               need to do this now. */
+            route = find_installed_route(prefix, plen);
+            if(route && route_metric(route) < INFINITY)
+                satisfy_request(prefix, plen, route->src->seqno, route->src->id,
+                                NULL);
+        }
+        return;
+    }
+
+    if(!if_up(ifp))
+        return;
+
+    babel_ifp = babel_get_if_nfo(ifp);
+    if(prefix) {
+        if(!parasitic || find_xroute(prefix, plen)) {
+            debugf(BABEL_DEBUG_COMMON,"Sending update to %s for %s.",
+                   ifp->name, format_prefix(prefix, plen));
+            buffer_update(ifp, prefix, plen);
+        }
+    } else {
+        if(!interface_idle(babel_ifp)) {
+            send_self_update(ifp);
+            if(!parasitic) {
+                debugf(BABEL_DEBUG_COMMON,"Sending update to %s for any.", ifp->name);
+                for(i = 0; i < numroutes; i++)
+                    if(routes[i].installed)
+                        buffer_update(ifp,
+                                      routes[i].src->prefix,
+                                      routes[i].src->plen);
+            }
+        }
+        set_timeout(&babel_ifp->update_timeout, babel_ifp->update_interval);
+    }
+    schedule_update_flush(ifp, urgent);
+}
+
+void
+send_update_resend(struct interface *ifp,
+                   const unsigned char *prefix, unsigned char plen)
+{
+    int delay;
+
+    assert(prefix != NULL);
+
+    send_update(ifp, 1, prefix, plen);
+
+    delay = 2000;
+    delay = MIN(delay, wireless_hello_interval / 2);
+    delay = MIN(delay, wired_hello_interval / 2);
+    delay = MAX(delay, 10);
+    record_resend(RESEND_UPDATE, prefix, plen, 0, 0, NULL, delay);
+}
+
+void
+send_wildcard_retraction(struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node)
+            send_wildcard_retraction(ifp_aux);
+        return;
+    }
+
+    if(!if_up(ifp))
+        return;
+
+    babel_ifp = babel_get_if_nfo(ifp);
+    start_message(ifp, MESSAGE_UPDATE, 10);
+    accumulate_byte(ifp, 0);
+    accumulate_byte(ifp, 0x40);
+    accumulate_byte(ifp, 0);
+    accumulate_byte(ifp, 0);
+    accumulate_short(ifp, 0xFFFF);
+    accumulate_short(ifp, myseqno);
+    accumulate_short(ifp, 0xFFFF);
+    end_message(ifp, MESSAGE_UPDATE, 10);
+
+    babel_ifp->have_buffered_id = 0;
+}
+
+void
+update_myseqno()
+{
+    myseqno = seqno_plus(myseqno, 1);
+    seqno_time = babel_now;
+}
+
+void
+send_self_update(struct interface *ifp)
+{
+    int i;
+
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node) {
+            if(!if_up(ifp_aux))
+                continue;
+            send_self_update(ifp_aux);
+        }
+        return;
+    }
+
+    if(!interface_idle(babel_get_if_nfo(ifp))) {
+        debugf(BABEL_DEBUG_COMMON,"Sending self update to %s.", ifp->name);
+        for(i = 0; i < numxroutes; i++)
+            send_update(ifp, 0, xroutes[i].prefix, xroutes[i].plen);
+    }
+}
+
+void
+send_ihu(struct neighbour *neigh, struct interface *ifp)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    int rxcost, interval;
+    int ll;
+
+    if(neigh == NULL && ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node) {
+            if(if_up(ifp_aux))
+                continue;
+            send_ihu(NULL, ifp_aux);
+        }
+        return;
+    }
+
+    if(neigh == NULL) {
+        struct neighbour *ngh;
+        FOR_ALL_NEIGHBOURS(ngh) {
+            if(ngh->ifp == ifp)
+                send_ihu(ngh, ifp);
+        }
+        return;
+    }
+
+
+    if(ifp && neigh->ifp != ifp)
+        return;
+
+    ifp = neigh->ifp;
+    babel_ifp = babel_get_if_nfo(ifp);
+    if(!if_up(ifp))
+        return;
+
+    rxcost = neighbour_rxcost(neigh);
+    interval = (babel_ifp->hello_interval * 3 + 9) / 10;
+
+    /* Conceptually, an IHU is a unicast message.  We usually send them as
+       multicast, since this allows aggregation into a single packet and
+       avoids an ARP exchange.  If we already have a unicast message queued
+       for this neighbour, however, we might as well piggyback the IHU. */
+    debugf(BABEL_DEBUG_COMMON,"Sending %sihu %d on %s to %s.",
+           unicast_neighbour == neigh ? "unicast " : "",
+           rxcost,
+           neigh->ifp->name,
+           format_address(neigh->address));
+
+    ll = linklocal(neigh->address);
+
+    if(unicast_neighbour != neigh) {
+        start_message(ifp, MESSAGE_IHU, ll ? 14 : 22);
+        accumulate_byte(ifp, ll ? 3 : 2);
+        accumulate_byte(ifp, 0);
+        accumulate_short(ifp, rxcost);
+        accumulate_short(ifp, interval);
+        if(ll)
+            accumulate_bytes(ifp, neigh->address + 8, 8);
+        else
+            accumulate_bytes(ifp, neigh->address, 16);
+        end_message(ifp, MESSAGE_IHU, ll ? 14 : 22);
+    } else {
+        int rc;
+        rc = start_unicast_message(neigh, MESSAGE_IHU, ll ? 14 : 22);
+        if(rc < 0) return;
+        accumulate_unicast_byte(neigh, ll ? 3 : 2);
+        accumulate_unicast_byte(neigh, 0);
+        accumulate_unicast_short(neigh, rxcost);
+        accumulate_unicast_short(neigh, interval);
+        if(ll)
+            accumulate_unicast_bytes(neigh, neigh->address + 8, 8);
+        else
+            accumulate_unicast_bytes(neigh, neigh->address, 16);
+        end_unicast_message(neigh, MESSAGE_IHU, ll ? 14 : 22);
+    }
+}
+
+/* Send IHUs to all marginal neighbours */
+void
+send_marginal_ihu(struct interface *ifp)
+{
+    struct neighbour *neigh;
+    FOR_ALL_NEIGHBOURS(neigh) {
+        if(ifp && neigh->ifp != ifp)
+            continue;
+        if(neigh->txcost >= 384 || (neigh->reach & 0xF000) != 0xF000)
+            send_ihu(neigh, ifp);
+    }
+}
+
+void
+send_request(struct interface *ifp,
+             const unsigned char *prefix, unsigned char plen)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    int v4, len;
+
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node) {
+            if(if_up(ifp_aux))
+                continue;
+            send_request(ifp_aux, prefix, plen);
+        }
+        return;
+    }
+
+    /* make sure any buffered updates go out before this request. */
+    flushupdates(ifp);
+
+    if(!if_up(ifp))
+        return;
+
+    babel_ifp = babel_get_if_nfo(ifp);
+    debugf(BABEL_DEBUG_COMMON,"sending request to %s for %s.",
+           ifp->name, prefix ? format_prefix(prefix, plen) : "any");
+    v4 = plen >= 96 && v4mapped(prefix);
+    len = !prefix ? 2 : v4 ? 6 : 18;
+
+    start_message(ifp, MESSAGE_REQUEST, len);
+    accumulate_byte(ifp, !prefix ? 0 : v4 ? 1 : 2);
+    accumulate_byte(ifp, !prefix ? 0 : v4 ? plen - 96 : plen);
+    if(prefix) {
+        if(v4)
+            accumulate_bytes(ifp, prefix + 12, 4);
+        else
+            accumulate_bytes(ifp, prefix, 16);
+    }
+    end_message(ifp, MESSAGE_REQUEST, len);
+}
+
+void
+send_unicast_request(struct neighbour *neigh,
+                     const unsigned char *prefix, unsigned char plen)
+{
+    int rc, v4, len;
+
+    /* make sure any buffered updates go out before this request. */
+    flushupdates(neigh->ifp);
+
+    debugf(BABEL_DEBUG_COMMON,"sending unicast request to %s for %s.",
+           format_address(neigh->address),
+           prefix ? format_prefix(prefix, plen) : "any");
+    v4 = plen >= 96 && v4mapped(prefix);
+    len = !prefix ? 2 : v4 ? 6 : 18;
+
+    rc = start_unicast_message(neigh, MESSAGE_REQUEST, len);
+    if(rc < 0) return;
+    accumulate_unicast_byte(neigh, !prefix ? 0 : v4 ? 1 : 2);
+    accumulate_unicast_byte(neigh, !prefix ? 0 : v4 ? plen - 96 : plen);
+    if(prefix) {
+        if(v4)
+            accumulate_unicast_bytes(neigh, prefix + 12, 4);
+        else
+            accumulate_unicast_bytes(neigh, prefix, 16);
+    }
+    end_unicast_message(neigh, MESSAGE_REQUEST, len);
+}
+
+void
+send_multihop_request(struct interface *ifp,
+                      const unsigned char *prefix, unsigned char plen,
+                      unsigned short seqno, const unsigned char *id,
+                      unsigned short hop_count)
+{
+    babel_interface_nfo *babel_ifp = NULL;
+    int v4, pb, len;
+
+    /* Make sure any buffered updates go out before this request. */
+    flushupdates(ifp);
+
+    if(ifp == NULL) {
+      struct interface *ifp_aux;
+      struct listnode *linklist_node = NULL;
+        FOR_ALL_INTERFACES(ifp_aux, linklist_node) {
+            if(!if_up(ifp_aux))
+                continue;
+            send_multihop_request(ifp_aux, prefix, plen, seqno, id, hop_count);
+        }
+        return;
+    }
+
+    if(!if_up(ifp))
+        return;
+
+    babel_ifp = babel_get_if_nfo(ifp);
+    debugf(BABEL_DEBUG_COMMON,"Sending request (%d) on %s for %s.",
+           hop_count, ifp->name, format_prefix(prefix, plen));
+    v4 = plen >= 96 && v4mapped(prefix);
+    pb = v4 ? ((plen - 96) + 7) / 8 : (plen + 7) / 8;
+    len = 6 + 8 + pb;
+
+    start_message(ifp, MESSAGE_MH_REQUEST, len);
+    accumulate_byte(ifp, v4 ? 1 : 2);
+    accumulate_byte(ifp, v4 ? plen - 96 : plen);
+    accumulate_short(ifp, seqno);
+    accumulate_byte(ifp, hop_count);
+    accumulate_byte(ifp, 0);
+    accumulate_bytes(ifp, id, 8);
+    if(prefix) {
+        if(v4)
+            accumulate_bytes(ifp, prefix + 12, pb);
+        else
+            accumulate_bytes(ifp, prefix, pb);
+    }
+    end_message(ifp, MESSAGE_MH_REQUEST, len);
+}
+
+void
+send_unicast_multihop_request(struct neighbour *neigh,
+                              const unsigned char *prefix, unsigned char plen,
+                              unsigned short seqno, const unsigned char *id,
+                              unsigned short hop_count)
+{
+    int rc, v4, pb, len;
+
+    /* Make sure any buffered updates go out before this request. */
+    flushupdates(neigh->ifp);
+
+    debugf(BABEL_DEBUG_COMMON,"Sending multi-hop request to %s for %s (%d hops).",
+           format_address(neigh->address),
+           format_prefix(prefix, plen), hop_count);
+    v4 = plen >= 96 && v4mapped(prefix);
+    pb = v4 ? ((plen - 96) + 7) / 8 : (plen + 7) / 8;
+    len = 6 + 8 + pb;
+
+    rc = start_unicast_message(neigh, MESSAGE_MH_REQUEST, len);
+    if(rc < 0) return;
+    accumulate_unicast_byte(neigh, v4 ? 1 : 2);
+    accumulate_unicast_byte(neigh, v4 ? plen - 96 : plen);
+    accumulate_unicast_short(neigh, seqno);
+    accumulate_unicast_byte(neigh, hop_count);
+    accumulate_unicast_byte(neigh, 0);
+    accumulate_unicast_bytes(neigh, id, 8);
+    if(prefix) {
+        if(v4)
+            accumulate_unicast_bytes(neigh, prefix + 12, pb);
+        else
+            accumulate_unicast_bytes(neigh, prefix, pb);
+    }
+    end_unicast_message(neigh, MESSAGE_MH_REQUEST, len);
+}
+
+void
+send_request_resend(struct neighbour *neigh,
+                    const unsigned char *prefix, unsigned char plen,
+                    unsigned short seqno, unsigned char *id)
+{
+    int delay;
+
+    if(neigh)
+        send_unicast_multihop_request(neigh, prefix, plen, seqno, id, 127);
+    else
+        send_multihop_request(NULL, prefix, plen, seqno, id, 127);
+
+    delay = 2000;
+    delay = MIN(delay, wireless_hello_interval / 2);
+    delay = MIN(delay, wired_hello_interval / 2);
+    delay = MAX(delay, 10);
+    record_resend(RESEND_REQUEST, prefix, plen, seqno, id,
+                  neigh ? neigh->ifp : NULL, delay);
+}
+
+void
+handle_request(struct neighbour *neigh, const unsigned char *prefix,
+               unsigned char plen, unsigned char hop_count,
+               unsigned short seqno, const unsigned char *id)
+{
+    struct xroute *xroute;
+    struct route *route;
+    struct neighbour *successor = NULL;
+
+    xroute = find_xroute(prefix, plen);
+    route = find_installed_route(prefix, plen);
+
+    if(xroute && (!route || xroute->metric <= kernel_metric)) {
+        if(hop_count > 0 && memcmp(id, myid, 8) == 0) {
+            if(seqno_compare(seqno, myseqno) > 0) {
+                if(seqno_minus(seqno, myseqno) > 100) {
+                    /* Hopelessly out-of-date request */
+                    return;
+                }
+                update_myseqno();
+            }
+        }
+        send_update(neigh->ifp, 1, prefix, plen);
+        return;
+    }
+
+    if(route &&
+       (memcmp(id, route->src->id, 8) != 0 ||
+        seqno_compare(seqno, route->seqno) <= 0)) {
+        send_update(neigh->ifp, 1, prefix, plen);
+        return;
+    }
+
+    if(hop_count <= 1)
+        return;
+
+    if(route && memcmp(id, route->src->id, 8) == 0 &&
+       seqno_minus(seqno, route->seqno) > 100) {
+        /* Hopelessly out-of-date */
+        return;
+    }
+
+    if(request_redundant(neigh->ifp, prefix, plen, seqno, id))
+        return;
+
+    /* Let's try to forward this request. */
+    if(route && route_metric(route) < INFINITY)
+        successor = route->neigh;
+
+    if(!successor || successor == neigh) {
+        /* We were about to forward a request to its requestor.  Try to
+           find a different neighbour to forward the request to. */
+        struct route *other_route;
+
+        other_route = find_best_route(prefix, plen, 0, neigh);
+        if(other_route && route_metric(other_route) < INFINITY)
+            successor = other_route->neigh;
+    }
+
+    if(!successor || successor == neigh)
+        /* Give up */
+        return;
+
+    send_unicast_multihop_request(successor, prefix, plen, seqno, id,
+                                  hop_count - 1);
+    record_resend(RESEND_REQUEST, prefix, plen, seqno, id,
+                  neigh->ifp, 0);
+}