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- /* vim: set expandtab ts=4 sw=4: */
- /*
- * You may redistribute this program and/or modify it under the terms of
- * the GNU General Public License as published by the Free Software Foundation,
- * either version 3 of the License, or (at your option) any later version.
- *
- * 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, see <http://www.gnu.org/licenses/>.
- */
- #include "interface/tuntap/TAPWrapper.h"
- #include "interface/tuntap/TUNMessageType.h"
- #include "util/Bits.h"
- #include "util/Identity.h"
- #include "util/AddrTools.h"
- #include "util/Defined.h"
- #include "wire/Message.h"
- #include "wire/Ethernet.h"
- #include "wire/Error.h"
- struct TAPWrapper_pvt
- {
- struct TAPWrapper pub;
- struct Iface external;
- struct Log* log;
- Identity
- };
- static Iface_DEFUN receiveMessage(struct Message* msg, struct Iface* external)
- {
- struct TAPWrapper_pvt* tw = Identity_containerOf(external, struct TAPWrapper_pvt, external);
- if (msg->length < Ethernet_SIZE-2) {
- Log_debug(tw->log, "runt");
- return 0;
- }
- // wacky 14 byte headers, back off into outer-space to create the padding...
- Message_shift(msg, 2, NULL);
- struct Ethernet eth;
- Message_pop(msg, ð, sizeof(struct Ethernet), NULL);
- // Not for us and not multicast...
- if (Bits_memcmp(eth.destAddr, TAPWrapper_LOCAL_MAC, Ethernet_ADDRLEN)
- && !(eth.destAddr[0] & 0x01))
- {
- if (Defined(Log_DEBUG)) {
- uint8_t printedMac[18];
- AddrTools_printMac(printedMac, eth.destAddr);
- Log_debug(tw->log, "Packet destine for unknown ethernet MAC [%s]", printedMac);
- }
- //return 0;
- }
- if (Bits_memcmp(eth.srcAddr, tw->pub.peerAddress, Ethernet_ADDRLEN)) {
- if (Bits_isZero(tw->pub.peerAddress, Ethernet_ADDRLEN)) {
- Bits_memcpy(tw->pub.peerAddress, eth.srcAddr, Ethernet_ADDRLEN);
- } else {
- #ifdef Log_DEBUG
- uint8_t printedMac[18];
- AddrTools_printMac(printedMac, eth.srcAddr);
- Log_debug(tw->log, "DROP Packet with unexpected source MAC [%s]", printedMac);
- #endif
- return 0;
- }
- }
- TUNMessageType_push(msg, eth.ethertype, NULL);
- return Iface_next(&tw->pub.internal, msg);
- }
- static Iface_DEFUN sendMessage(struct Message* msg, struct Iface* internal)
- {
- struct TAPWrapper_pvt* tw = Identity_containerOf(internal, struct TAPWrapper_pvt, pub.internal);
- uint16_t etherType = TUNMessageType_pop(msg, NULL);
- struct Ethernet eth = { .ethertype = etherType };
- Bits_memcpy(eth.srcAddr, TAPWrapper_LOCAL_MAC, Ethernet_ADDRLEN);
- Bits_memcpy(eth.destAddr, tw->pub.peerAddress, Ethernet_ADDRLEN);
- if (Bits_isZero(tw->pub.peerAddress, Ethernet_ADDRLEN)) {
- Log_debug(tw->log, "DROP Packet because peers MAC is not yet known");
- return NULL;
- }
- Message_push(msg, ð, sizeof(struct Ethernet), NULL);
- // struct Ethernet contains 2 bytes of padding at the beginning.
- Message_shift(msg, -2, NULL);
- return Iface_next(&tw->external, msg);
- }
- struct TAPWrapper* TAPWrapper_new(struct Iface* external,
- struct Log* log,
- struct Allocator* alloc)
- {
- struct TAPWrapper_pvt* out = Allocator_calloc(alloc, sizeof(struct TAPWrapper_pvt), 1);
- Identity_set(out);
- out->log = log;
- out->external.send = receiveMessage;
- out->pub.internal.send = sendMessage;
- Iface_plumb(external, &out->external);
- return &out->pub;
- }
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