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/*
* Copyright (c) 2009, 2010 Nicira Networks.
*
* 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 <config.h>
#include "packets.h"
#include <netinet/in.h>
#include <stdlib.h>
#include "ofpbuf.h"
/* Parses 's' as a 16-digit hexadecimal number representing a datapath ID. On
* success stores the dpid into '*dpidp' and returns true, on failure stores 0
* into '*dpidp' and returns false.
*
* Rejects an all-zeros dpid as invalid. */
bool
dpid_from_string(const char *s, uint64_t *dpidp)
{
*dpidp = (strlen(s) == 16 && strspn(s, "0123456789abcdefABCDEF") == 16
? strtoull(s, NULL, 16)
: 0);
return *dpidp != 0;
}
bool
eth_addr_from_string(const char *s, uint8_t ea[ETH_ADDR_LEN])
{
if (sscanf(s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(ea))
== ETH_ADDR_SCAN_COUNT) {
return true;
} else {
memset(ea, 0, ETH_ADDR_LEN);
return false;
}
}
/* Fills 'b' with an 802.2 SNAP packet with Ethernet source address 'eth_src',
* the Nicira OUI as SNAP organization and 'snap_type' as SNAP type. The text
* string in 'tag' is enclosed as the packet payload.
*
* This function is used by Open vSwitch to compose packets in cases where
* context is important but content doesn't (or shouldn't) matter. For this
* purpose, 'snap_type' should be a random number and 'tag' should be an
* English phrase that explains the purpose of the packet. (The English phrase
* gives hapless admins running Wireshark the opportunity to figure out what's
* going on.) */
void
compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
const uint8_t eth_src[ETH_ADDR_LEN])
{
struct eth_header *eth;
struct llc_snap_header *llc_snap;
/* Compose basic packet structure. (We need the payload size to stick into
* the 802.2 header.) */
ofpbuf_clear(b);
eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN);
llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN);
ofpbuf_put(b, tag, strlen(tag) + 1); /* Includes null byte. */
ofpbuf_put(b, eth_src, ETH_ADDR_LEN);
/* Compose 802.2 header. */
memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
eth->eth_type = htons(b->size - ETH_HEADER_LEN);
/* Compose LLC, SNAP headers. */
llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
memcpy(llc_snap->snap.snap_org, "\x00\x23\x20", 3);
llc_snap->snap.snap_type = htons(snap_type);
}
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