cdp_periodic.c

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/*
 * Copyright (c) 2011-2016 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <vnet/cdp/cdp_node.h>
#include <vppinfra/hash.h>
#include <vnet/unix/pcap.h>
#include <vnet/srp/srp.h>
#include <vnet/ppp/ppp.h>
#include <vnet/hdlc/hdlc.h>
#include <vnet/srp/packet.h>

/*
 * Generate a set of specific CDP TLVs.
 *
 * $$$ eventually these need to fish better data from
 * other data structures; e.g. the hostname, software version info
 * etc.
 */

static void add_device_name_tlv (vnet_hw_interface_t *hw, u8 **t0p)
{
    cdp_tlv_t *t = (cdp_tlv_t *) *t0p;

    t->t = htons(CDP_TLV_device_name);
    t->l = htons(3 + sizeof (*t));
    clib_memcpy (&t->v, "VPP", 3);
    
    *t0p += ntohs(t->l);
}

static void add_port_id_tlv (vnet_hw_interface_t *hw, u8 **t0p)
{
    cdp_tlv_t *t = (cdp_tlv_t *) *t0p;

    t->t = htons(CDP_TLV_port_id);
    t->l = htons(vec_len(hw->name) + sizeof (*t));
    clib_memcpy (&t->v, hw->name, vec_len (hw->name));
    *t0p += ntohs(t->l);
}

static void add_version_tlv (vnet_hw_interface_t *hw, u8 **t0p)
{
    cdp_tlv_t *t = (cdp_tlv_t *) *t0p;

    t->t = htons(CDP_TLV_version);
    t->l = htons(12 + sizeof (*t));
    clib_memcpy (&t->v, "VPP Software", 12);
    *t0p += ntohs(t->l);
}

static void add_platform_tlv (vnet_hw_interface_t *hw, u8 **t0p)
{
    cdp_tlv_t *t = (cdp_tlv_t *) *t0p;

    t->t = htons(CDP_TLV_platform);
    t->l = htons(2 + sizeof (*t));
    clib_memcpy (&t->v, "SW", 2);
    *t0p += ntohs(t->l);
}

static void add_capability_tlv (vnet_hw_interface_t *hw, u8 **t0p)
{
    cdp_tlv_t *t = (cdp_tlv_t *) *t0p;
    u32 capabilities;

    t->t = htons(CDP_TLV_capabilities);
    t->l = htons(4 + sizeof (*t));
    capabilities = CDP_ROUTER_DEVICE;
    capabilities = htonl (capabilities);
    clib_memcpy (&t->v, &capabilities, sizeof (capabilities));
    *t0p += ntohs(t->l);
}

static void add_tlvs (cdp_main_t *cm, vnet_hw_interface_t *hw, u8 **t0p)
{
    add_device_name_tlv (hw, t0p);
    add_port_id_tlv (hw, t0p);
    add_version_tlv (hw, t0p);
    add_platform_tlv (hw, t0p);
    add_capability_tlv (hw, t0p);
}

/*
 * send a cdp pkt on an ethernet interface
 */
static void 
send_ethernet_hello (cdp_main_t *cm, cdp_neighbor_t *n, int count)
{
    u32 * to_next;
    ethernet_llc_snap_and_cdp_header_t *h0;
    vnet_hw_interface_t *hw;
    u32 bi0;
    vlib_buffer_t *b0;
    u8 *t0;
    u16 checksum;
    int nbytes_to_checksum;
    int i;
    vlib_frame_t * f;
    vlib_main_t * vm = cm->vlib_main;
    vnet_main_t * vnm = cm->vnet_main;

    for (i = 0; i < count; i++) {
        /* 
         * see cdp_periodic_init() to understand what's already painted
         * into the buffer by the packet template mechanism  
         */
        h0 = vlib_packet_template_get_packet 
            (vm, 
             &cm->packet_templates[n->packet_template_index], &bi0);
        
        /* Add the interface's ethernet source address */
        hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);
        
        clib_memcpy (h0->ethernet.src_address, hw->hw_address, 
                vec_len (hw->hw_address));
        
        t0 = (u8 *) &h0->cdp.data;

        /* add TLVs */
        add_tlvs (cm, hw, &t0);
        
        /* add the cdp packet checksum */
        nbytes_to_checksum = t0 - (u8 *)&h0->cdp;
        checksum = cdp_checksum (&h0->cdp, nbytes_to_checksum);
        h0->cdp.checksum = htons (checksum);
        
        /* Set the outbound packet length */
        b0 = vlib_get_buffer (vm, bi0);
        b0->current_length = nbytes_to_checksum + sizeof (*h0) 
            - sizeof (cdp_hdr_t) ;

       /* And the outbound interface */
        vnet_buffer(b0)->sw_if_index[VLIB_TX] = hw->sw_if_index;

        /* Set the 802.3 ethernet length */
        h0->ethernet.len = htons (b0->current_length
                                  - sizeof (ethernet_802_3_header_t));

        /* And output the packet on the correct interface */
        f = vlib_get_frame_to_node (vm, hw->output_node_index);
        to_next = vlib_frame_vector_args (f);
        to_next[0] = bi0;
        f->n_vectors = 1;

        vlib_put_frame_to_node (vm, hw->output_node_index, f);
        n->last_sent = vlib_time_now (vm);
    }
}

/*
 * send a cdp pkt on an hdlc interface
 */
static void 
send_hdlc_hello (cdp_main_t *cm, cdp_neighbor_t *n, int count)
{
    u32 * to_next;
    hdlc_and_cdp_header_t *h0;
    vnet_hw_interface_t *hw;
    u32 bi0;
    vlib_buffer_t *b0;
    u8 *t0;
    u16 checksum;
    int nbytes_to_checksum;
    int i;
    vlib_frame_t * f;
    vlib_main_t * vm = cm->vlib_main;
    vnet_main_t * vnm = cm->vnet_main;

    for (i = 0; i < count; i++) {
        /* 
         * see cdp_periodic_init() to understand what's already painted
         * into the buffer by the packet template mechanism  
         */
        h0 = vlib_packet_template_get_packet 
            (vm, 
             &cm->packet_templates[n->packet_template_index], &bi0);
        
        hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);

        t0 = (u8 *) &h0->cdp.data;

        /* add TLVs */
        add_tlvs (cm, hw, &t0);
        
        /* add the cdp packet checksum */
        nbytes_to_checksum = t0 - (u8 *)&h0->cdp;
        checksum = cdp_checksum (&h0->cdp, nbytes_to_checksum);
        h0->cdp.checksum = htons (checksum);
        
        /* Set the outbound packet length */
        b0 = vlib_get_buffer (vm, bi0);
        b0->current_length = nbytes_to_checksum + sizeof (*h0) 
            - sizeof (cdp_hdr_t) ;

        /* And output the packet on the correct interface */
        f = vlib_get_frame_to_node (vm, hw->output_node_index);
        to_next = vlib_frame_vector_args (f);
        to_next[0] = bi0;
        f->n_vectors = 1;

        vlib_put_frame_to_node (vm, hw->output_node_index, f);
        n->last_sent = vlib_time_now (vm);
    }
}

/*
 * send a cdp pkt on an srp interface
 */
static void 
send_srp_hello (cdp_main_t *cm, cdp_neighbor_t *n, int count)
{
    u32 * to_next;
    srp_and_cdp_header_t *h0;
    vnet_hw_interface_t *hw;
    u32 bi0;
    vlib_buffer_t *b0;
    u8 *t0;
    u16 checksum;
    int nbytes_to_checksum;
    int i;
    vlib_frame_t * f;
    vlib_main_t * vm = cm->vlib_main;
    vnet_main_t * vnm = cm->vnet_main;

    for (i = 0; i < count; i++) {
        /* 
         * see cdp_periodic_init() to understand what's already painted
         * into the buffer by the packet template mechanism  
         */
        h0 = vlib_packet_template_get_packet 
            (vm, 
             &cm->packet_templates[n->packet_template_index], &bi0);
        
        hw = vnet_get_sup_hw_interface (vnm, n->sw_if_index);

        t0 = (u8 *) &h0->cdp.data;

        /* add TLVs */
        add_tlvs (cm, hw, &t0);
        
        /* Add the interface's ethernet source address */
        clib_memcpy (h0->ethernet.src_address, hw->hw_address, 
                vec_len (hw->hw_address));

        /* add the cdp packet checksum */
        nbytes_to_checksum = t0 - (u8 *)&h0->cdp;
        checksum = cdp_checksum (&h0->cdp, nbytes_to_checksum);
        h0->cdp.checksum = htons (checksum);
        
        /* Set the outbound packet length */
        b0 = vlib_get_buffer (vm, bi0);
        b0->current_length = nbytes_to_checksum + sizeof (*h0) 
            - sizeof (cdp_hdr_t) ;

        /* And output the packet on the correct interface */
        f = vlib_get_frame_to_node (vm, hw->output_node_index);
        to_next = vlib_frame_vector_args (f);
        to_next[0] = bi0;
        f->n_vectors = 1;

        vlib_put_frame_to_node (vm, hw->output_node_index, f);
        n->last_sent = vlib_time_now (vm);
    }
}

/*
 * Decide which cdp packet template to use
 */
static int pick_packet_template (cdp_main_t *cm, cdp_neighbor_t *n)
{
    n->packet_template_index = CDP_PACKET_TEMPLATE_ETHERNET;

    return 0;
}

/* Send a cdp neighbor announcement */
static void send_hello (cdp_main_t *cm, cdp_neighbor_t *n, int count)
{
    if (n->packet_template_index == (u8)~0) {
        /* If we don't know how to talk to this peer, don't try again */
        if (pick_packet_template (cm, n)) {
            n->last_sent = 1e70;
            return;
        }
    }

    switch (n->packet_template_index)
    {
    case CDP_PACKET_TEMPLATE_ETHERNET:
        send_ethernet_hello (cm, n, count);
        break;

    case CDP_PACKET_TEMPLATE_HDLC:
        send_hdlc_hello (cm, n, count);
        break;

    case CDP_PACKET_TEMPLATE_SRP:
        send_srp_hello (cm, n, count);
        break;

    default:
        ASSERT(0);
    }
    n->last_sent = vlib_time_now (cm->vlib_main);
}

static void delete_neighbor (cdp_main_t *cm, cdp_neighbor_t *n,
                             int want_broadcast)
{
    hash_unset (cm->neighbor_by_sw_if_index, n->sw_if_index);
    vec_free (n->device_name);
    vec_free (n->version);
    vec_free (n->port_id);
    vec_free (n->platform);
    vec_free (n->last_rx_pkt);
    pool_put (cm->neighbors, n);
}

void cdp_periodic (vlib_main_t * vm)
{
    cdp_main_t *cm = &cdp_main;
    cdp_neighbor_t *n;
    f64 now = vlib_time_now (vm);
    vnet_sw_interface_t *sw;
    static u32 * delete_list = 0;
    int i;
    static cdp_neighbor_t **n_list = 0;

    pool_foreach (n, cm->neighbors, 
    ({
      vec_add1 (n_list, n);
    }));

    /* Across all cdp neighbors known to the system */
    for (i = 0; i < vec_len (n_list); i++) {
        n = n_list[i];

        /* "no cdp run" provisioned on the interface? */
        if (n->disabled == 1)
            continue;

        sw = vnet_get_sw_interface (cm->vnet_main, n->sw_if_index);

        /* Interface shutdown or rx timeout? */
        if (!(sw->flags & VNET_SW_INTERFACE_FLAG_ADMIN_UP)
            || (now > (n->last_heard + (f64)n->ttl_in_seconds)))
            /* add to list of neighbors to delete */
            vec_add1 (delete_list, n - cm->neighbors);
        else if (n->last_sent == 0.0)
            /* First time, send 3 hellos */
            send_hello (cm, n, 3 /* three to begin with */);
        else if (now > (n->last_sent + (((f64)n->ttl_in_seconds)/6.0)))
            /* Normal keepalive, send one */
            send_hello (cm, n, 1 /* one as a keepalive */);
    }
        
    for (i = 0; i < vec_len (delete_list); i++) {
        n = vec_elt_at_index (cm->neighbors, delete_list[i]);
        delete_neighbor (cm, n, 1);
    }
    if (delete_list)
        _vec_len (delete_list) = 0;
    if (n_list)
        _vec_len (n_list) = 0;
}

static clib_error_t *cdp_periodic_init (vlib_main_t * vm)
{
    cdp_main_t * cm = &cdp_main;

    /* Create the ethernet cdp hello packet template */
    {
        ethernet_llc_snap_and_cdp_header_t h;

        memset (&h, 0, sizeof (h));
        
        /* Send to 01:00:0c:cc:cc */
        h.ethernet.dst_address[0] = 0x01;
        /* h.ethernet.dst_address[1] = 0x00; (memset) */
        h.ethernet.dst_address[2] = 0x0C;
        h.ethernet.dst_address[3] = 0xCC;
        h.ethernet.dst_address[4] = 0xCC;
        h.ethernet.dst_address[5] = 0xCC;
        
        /* leave src address blank (fill in at send time) */
        
        /* leave length blank (fill in at send time) */
        
        /* LLC */
        h.llc.dst_sap = h.llc.src_sap = 0xAA; /* SNAP */
        h.llc.control = 0x03;       /* UI (no extended control bytes) */
        
        /* SNAP */
        /* h.snap.oui[0] = 0x00; (memset) */
        /* h.snap.oui[1] = 0x00; (memset) */
        h.snap.oui[2] = 0x0C;       /* Cisco = 0x00000C */
        h.snap.protocol = htons (0x2000); /* CDP = 0x2000 */
        
        /* CDP */
        h.cdp.version = 2;
        h.cdp.ttl = 180;
        
        vlib_packet_template_init 
            (vm,
             &cm->packet_templates[CDP_PACKET_TEMPLATE_ETHERNET],
             /* data */ &h,
             sizeof (h),
             /* alloc chunk size */ 8,
             "cdp-ethernet");
    }

#if 0 /* retain for reference */

    /* Create the hdlc cdp hello packet template */
    {
        hdlc_and_cdp_header_t h;

        memset (&h, 0, sizeof (h));

        h.hdlc.address = 0x0f;
        /* h.hdlc.control = 0; (memset) */
        h.hdlc.protocol = htons (0x2000); /* CDP = 0x2000 */

        /* CDP */
        h.cdp.version = 2;
        h.cdp.ttl = 180;

        vlib_packet_template_init 
            (vm,
             &cm->packet_templates[CDP_PACKET_TEMPLATE_HDLC],
             /* data */ &h,
             sizeof (h),
             /* alloc chunk size */ 8,
             "cdp-hdlc");
    }

    /* Create the srp cdp hello packet template */
    {
        srp_and_cdp_header_t h;

        memset (&h, 0, sizeof (h));
        
        /* Send to 01:00:0c:cc:cc */
        h.ethernet.dst_address[0] = 0x01;
        /* h.ethernet.dst_address[1] = 0x00; (memset) */
        h.ethernet.dst_address[2] = 0x0C;
        h.ethernet.dst_address[3] = 0xCC;
        h.ethernet.dst_address[4] = 0xCC;
        h.ethernet.dst_address[5] = 0xCC;
        
        /* leave src address blank (fill in at send time) */
        
        /* The srp header is filled in at xmt */
        h.srp.ttl = 1;
        h.srp.priority = 7;
        h.srp.mode = SRP_MODE_data;
        srp_header_compute_parity (&h.srp);

        /* Inner ring and parity will be set at send time */

        h.ethernet.type = htons (0x2000); /* CDP = 0x2000 */

        /* CDP */
        h.cdp.version = 2;
        h.cdp.ttl = 180;
        
        vlib_packet_template_init 
            (vm,
             &cm->packet_templates[CDP_PACKET_TEMPLATE_SRP],
             /* data */ &h,
             sizeof (h),
             /* alloc chunk size */ 8,
             "cdp-srp");
    }
#endif

    return 0;
}

VLIB_INIT_FUNCTION (cdp_periodic_init);