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Reorganize tap code so that more than one method can be used

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for accessing physical packets.
Add support for tap devices found on linux and bsd.

--HG--
extra : convert_revision : 198b082f2e847da8471c3f22d6a55beb9f4b592e
This commit is contained in:
Nathan Binkert 2005-06-27 19:30:19 -04:00
parent 10a906be52
commit 769234f69e
1 changed files with 154 additions and 38 deletions
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192
util/tap/tap.cc
View file

@ -173,7 +173,7 @@ Accept(int fd, bool nodelay)
}
void
Connect(int fd, const string &host, int port)
Connect(int fd, const std::string &host, int port)
{
struct sockaddr_in sockaddr;
if (::inet_aton(host.c_str(), &sockaddr.sin_addr) == 0) {
@ -193,6 +193,133 @@ Connect(int fd, const string &host, int port)
DPRINTF("connected to %s on port %d\n", host, port);
}
class Ethernet
{
protected:
int fd;
public:
virtual ~Ethernet() {}
int getfd() const { return fd; }
virtual bool read(const char *&data, int &len) = 0;
virtual bool write(const char *data, int len) = 0;
};
class Tap : public Ethernet
{
private:
char buffer[65536];
int fd;
public:
Tap(char *device);
~Tap();
virtual bool read(const char *&data, int &len);
virtual bool write(const char *data, int len);
};
class PCap : public Ethernet
{
private:
pcap_t *pcap;
eth_t *ethernet;
public:
PCap(char *device, char *filter = NULL);
~PCap();
virtual bool read(const char *&data, int &len);
virtual bool write(const char *data, int len);
};
PCap::PCap(char *device, char *filter)
{
char errbuf[PCAP_ERRBUF_SIZE];
memset(errbuf, 0, sizeof errbuf);
pcap = pcap_open_live(device, 1500, 1, -1, errbuf);
if (pcap == NULL)
panic("pcap_open_live failed: %s\n", errbuf);
if (filter) {
bpf_program program;
bpf_u_int32 localnet, netmask;
if (pcap_lookupnet(device, &localnet, &netmask, errbuf) == -1) {
DPRINTF("pcap_lookupnet failed: %s\n", errbuf);
netmask = 0xffffff00;
}
if (pcap_compile(pcap, &program, filter, 1, netmask) == -1)
panic("pcap_compile failed, invalid filter:\n%s\n", filter);
if (pcap_setfilter(pcap, &program) == -1)
panic("pcap_setfilter failed\n");
}
ethernet = eth_open(device);
if (!ethernet)
panic("cannot open the ethernet device for writing\n");
fd = pcap_fileno(pcap);
}
PCap::~PCap()
{
pcap_close(pcap);
eth_close(ethernet);
}
bool
PCap::read(const char *&data, int &len)
{
pcap_pkthdr hdr;
data = (const char *)pcap_next(pcap, &hdr);
if (!data)
return false;
len = hdr.len;
return true;
}
bool
PCap::write(const char *data, int len)
{
eth_send(ethernet, data, len);
}
Tap::Tap(char *device)
{
fd = open(device, O_RDWR, 0);
if (fd < 0)
panic("could not open %s: %s\n", device, strerror(errno));
}
Tap::~Tap()
{
close(fd);
}
bool
Tap::read(const char *&data, int &len)
{
DPRINTF("tap read!\n");
data = buffer;
len = ::read(fd, buffer, sizeof(buffer));
if (len < 0)
return false;
return true;
}
bool
Tap::write(const char *data, int len)
{
int result = ::write(fd, data, len);
if (result < 0)
return false;
return true;
}
int
main(int argc, char *argv[])
{
@ -201,13 +328,16 @@ main(int argc, char *argv[])
bool listening = false;
char *device = NULL;
char *filter = NULL;
Ethernet *tap = NULL;
bool usetap = false;
char c;
int daemon = false;
string host;
std::string host;
int devfd;
program = basename(argv[0]);
while ((c = getopt(argc, argv, "b:df:lp:v")) != -1) {
while ((c = getopt(argc, argv, "b:df:lp:tv")) != -1) {
switch (c) {
case 'b':
bufsize = atoi(optarg);
@ -224,6 +354,9 @@ main(int argc, char *argv[])
case 'p':
port = atoi(optarg);
break;
case 't':
usetap = true;
break;
case 'v':
verbose++;
break;
@ -268,31 +401,14 @@ main(int argc, char *argv[])
host = *argv;
}
char errbuf[PCAP_ERRBUF_SIZE];
memset(errbuf, 0, sizeof errbuf);
pcap_t *pcap = pcap_open_live(device, 1500, 1, -1, errbuf);
if (pcap == NULL)
panic("pcap_open_live failed: %s\n", errbuf);
if (filter) {
bpf_program program;
bpf_u_int32 localnet, netmask;
if (pcap_lookupnet(device, &localnet, &netmask, errbuf) == -1) {
DPRINTF("pcap_lookupnet failed: %s\n", errbuf);
netmask = 0xffffff00;
}
if (pcap_compile(pcap, &program, filter, 1, netmask) == -1)
panic("pcap_compile failed, invalid filter:\n%s\n", filter);
if (pcap_setfilter(pcap, &program) == -1)
panic("pcap_setfilter failed\n");
if (usetap) {
if (filter)
panic("-f parameter not valid with a tap device!");
tap = new Tap(device);
} else {
tap = new PCap(device, filter);
}
eth_t *ethernet = eth_open(device);
if (!ethernet)
panic("cannot open the ethernet device for writing\n");
pollfd pfds[3];
pfds[0].fd = Socket(true);
pfds[0].events = POLLIN;
@ -303,7 +419,7 @@ main(int argc, char *argv[])
else
Connect(pfds[0].fd, host, port);
pfds[1].fd = pcap_fileno(pcap);
pfds[1].fd = tap->getfd();
pfds[1].events = POLLIN;
pfds[1].revents = 0;
@ -341,16 +457,16 @@ main(int argc, char *argv[])
listen_pfd->revents = 0;
}
DPRINTF("tap events: %x\n", tap_pfd->revents);
if (tap_pfd && tap_pfd->revents) {
if (tap_pfd->revents & POLLIN) {
pcap_pkthdr hdr;
const u_char *data = pcap_next(pcap, &hdr);
if (data && client_pfd) {
DPRINTF("Received packet from ethernet len=%d\n", hdr.len);
DDUMP(data, hdr.len);
u_int32_t len = htonl(hdr.len);
write(client_pfd->fd, &len, sizeof(len));
write(client_pfd->fd, data, hdr.len);
const char *data; int len;
if (tap->read(data, len) && client_pfd) {
DPRINTF("Received packet from ethernet len=%d\n", len);
DDUMP(data, len);
u_int32_t swaplen = htonl(len);
write(client_pfd->fd, &swaplen, sizeof(swaplen));
write(client_pfd->fd, data, len);
}
}
@ -379,7 +495,7 @@ main(int argc, char *argv[])
while (data_len != 0 &&
buffer_offset >= data_len + sizeof(u_int32_t)) {
char *data = buffer + sizeof(u_int32_t);
eth_send(ethernet, data, data_len);
tap->write(data, data_len);
DPRINTF("Sent packet to ethernet len = %d\n", data_len);
DDUMP(data, data_len);
@ -412,8 +528,8 @@ main(int argc, char *argv[])
}
delete [] buffer;
pcap_close(pcap);
eth_close(ethernet);
delete tap;
if (listen_pfd)
close(listen_pfd->fd);