/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
 * Junior University
 * 
 * We are making the OpenFlow specification and associated documentation
 * (Software) available for public use and benefit with the expectation
 * that others will use, modify and enhance the Software and contribute
 * those enhancements back to the community. However, since we would
 * like to make the Software available for broadest use, with as few
 * restrictions as possible permission is hereby granted, free of
 * charge, to any person obtaining a copy of this Software to deal in
 * the Software under the copyrights 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.
 * 
 * The name and trademarks of copyright holder(s) may NOT be used in
 * advertising or publicity pertaining to the Software or any
 * derivatives without specific, written prior permission.
 */

#include <config.h>
#include "vconn.h"
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include "buffer.h"
#include "flow.h"
#include "ofp-print.h"
#include "openflow.h"
#include "poll-loop.h"
#include "random.h"
#include "util.h"

#define THIS_MODULE VLM_vconn
#include "vlog.h"

static struct vconn_class *vconn_classes[] = {
    &tcp_vconn_class,
    &ptcp_vconn_class,
#ifdef HAVE_NETLINK
    &netlink_vconn_class,
#endif
#ifdef HAVE_OPENSSL
    &ssl_vconn_class,
    &pssl_vconn_class,
#endif
    &unix_vconn_class,
    &punix_vconn_class,
};

/* Check the validity of the vconn class structures. */
static void
check_vconn_classes(void)
{
#ifndef NDEBUG
    size_t i;

    for (i = 0; i < ARRAY_SIZE(vconn_classes); i++) {
        struct vconn_class *class = vconn_classes[i];
        assert(class->name != NULL);
        assert(class->open != NULL);
        if (class->close || class->accept || class->recv || class->send
            || class->wait) {
            assert(class->close != NULL);
            assert(class->accept
                   ? !class->recv && !class->send
                   :  class->recv && class->send);
            assert(class->wait != NULL);
        } else {
            /* This class delegates to another one. */
        }
    }
#endif
}

/* Prints information on active (if 'active') and passive (if 'passive')
 * connection methods supported by the vconn. */
void
vconn_usage(bool active, bool passive)
{
    /* Really this should be implemented via callbacks into the vconn
     * providers, but that seems too heavy-weight to bother with at the
     * moment. */
    
    printf("\n");
    if (active) {
        printf("Active OpenFlow connection methods:\n");
#ifdef HAVE_NETLINK
        printf("  nl:DP_IDX               "
               "local datapath DP_IDX\n");
#endif
        printf("  tcp:HOST[:PORT]         "
               "PORT (default: %d) on remote TCP HOST\n", OFP_TCP_PORT);
#ifdef HAVE_OPENSSL
        printf("  ssl:HOST[:PORT]         "
               "SSL PORT (default: %d) on remote HOST\n", OFP_SSL_PORT);
#endif
        printf("  unix:FILE               Unix domain socket named FILE\n");
    }

    if (passive) {
        printf("Passive OpenFlow connection methods:\n");
        printf("  ptcp:[PORT]             "
               "listen to TCP PORT (default: %d)\n",
               OFP_TCP_PORT);
#ifdef HAVE_OPENSSL
        printf("  pssl:[PORT]             "
               "listen for SSL on PORT (default: %d)\n",
               OFP_SSL_PORT);
#endif
        printf("  punix:FILE              "
               "listen on Unix domain socket FILE\n");
    }

#ifdef HAVE_OPENSSL
    printf("PKI configuration (required to use SSL):\n"
           "  -p, --private-key=FILE  file with private key\n"
           "  -c, --certificate=FILE  file with certificate for private key\n"
           "  -C, --ca-cert=FILE      file with peer CA certificate\n");
#endif
}

/* Attempts to connect to an OpenFlow device.  'name' is a connection name in
 * the form "TYPE:ARGS", where TYPE is the vconn class's name and ARGS are
 * vconn class-specific.
 *
 * Returns 0 if successful, otherwise a positive errno value.  If successful,
 * stores a pointer to the new connection in '*vconnp', otherwise a null
 * pointer.  */
int
vconn_open(const char *name, struct vconn **vconnp)
{
    size_t prefix_len;
    size_t i;

    check_vconn_classes();

    prefix_len = strcspn(name, ":");
    if (prefix_len == strlen(name)) {
        error(0, "`%s' not correct format for peer name", name);
        return EAFNOSUPPORT;
    }
    for (i = 0; i < ARRAY_SIZE(vconn_classes); i++) {
        struct vconn_class *class = vconn_classes[i];
        if (strlen(class->name) == prefix_len
            && !memcmp(class->name, name, prefix_len)) {
            char *suffix_copy = xstrdup(name + prefix_len + 1);
            int retval = class->open(name, suffix_copy, vconnp);
            free(suffix_copy);
            if (retval) {
                *vconnp = NULL;
            } else {
                assert((*vconnp)->connect_status != EAGAIN
                       || (*vconnp)->class->connect);
            }
            return retval;
        }
    }
    error(0, "unknown peer type `%.*s'", (int) prefix_len, name);
    return EAFNOSUPPORT;
}

int
vconn_open_block(const char *name, struct vconn **vconnp)
{
    struct vconn *vconn;
    int error;

    error = vconn_open(name, &vconn);
    while (error == EAGAIN) {
        vconn_connect_wait(vconn);
        poll_block();
        error = vconn_connect(vconn);
        assert(error != EINPROGRESS);
    }
    if (error) {
        vconn_close(vconn);
        *vconnp = NULL;
    } else {
        *vconnp = vconn;
    }
    return error;
}

/* Closes 'vconn'. */
void
vconn_close(struct vconn *vconn)
{
    if (vconn != NULL) {
        (vconn->class->close)(vconn);
    }
}

/* Returns true if 'vconn' is a passive vconn, that is, its purpose is to
 * wait for connections to arrive, not to transfer data.  Returns false if
 * 'vconn' is an active vconn, that is, its purpose is to transfer data, not
 * to wait for new connections to arrive. */
bool
vconn_is_passive(const struct vconn *vconn)
{
    return vconn->class->accept != NULL;
}

/* Returns the IP address of the peer, or 0 if the peer is not connected over
 * an IP-based protocol or if its IP address is not yet known. */
uint32_t
vconn_get_ip(const struct vconn *vconn) 
{
    return vconn->ip;
}

/* Tries to complete the connection on 'vconn', which must be an active
 * vconn.  If 'vconn''s connection is complete, returns 0 if the connection
 * was successful or a positive errno value if it failed.  If the
 * connection is still in progress, returns EAGAIN. */
int
vconn_connect(struct vconn *vconn)
{
    if (vconn->connect_status == EAGAIN) {
        vconn->connect_status = (vconn->class->connect)(vconn);
        assert(vconn->connect_status != EINPROGRESS);
    }
    return vconn->connect_status;
}

/* Tries to accept a new connection on 'vconn', which must be a passive vconn.
 * If successful, stores the new connection in '*new_vconn' and returns 0.
 * Otherwise, returns a positive errno value.
 *
 * vconn_accept will not block waiting for a connection.  If no connection is
 * ready to be accepted, it returns EAGAIN immediately. */
int
vconn_accept(struct vconn *vconn, struct vconn **new_vconn)
{
    int retval;

    retval = (vconn->class->accept)(vconn, new_vconn);

    if (retval) {
        *new_vconn = NULL;
    } else {
        assert((*new_vconn)->connect_status != EAGAIN
               || (*new_vconn)->class->connect);
    }
    return retval;
}

/* Tries to receive an OpenFlow message from 'vconn', which must be an active
 * vconn.  If successful, stores the received message into '*msgp' and returns
 * 0.  The caller is responsible for destroying the message with
 * buffer_delete().  On failure, returns a positive errno value and stores a
 * null pointer into '*msgp'.  On normal connection close, returns EOF.
 *
 * vconn_recv will not block waiting for a packet to arrive.  If no packets
 * have been received, it returns EAGAIN immediately. */
int
vconn_recv(struct vconn *vconn, struct buffer **msgp)
{
    int retval = vconn_connect(vconn);
    if (!retval) {
        retval = (vconn->class->recv)(vconn, msgp);
        if (!retval) {
            struct ofp_header *oh;

            if (VLOG_IS_DBG_ENABLED()) {
                char *s = ofp_to_string((*msgp)->data, (*msgp)->size, 1);
                VLOG_DBG("received: %s", s);
                free(s);
            }

            oh = buffer_at_assert(*msgp, 0, sizeof *oh);
            if (oh->version != OFP_VERSION) {
                VLOG_ERR("received OpenFlow version %02"PRIx8" "
                         "!= expected %02x",
                         oh->version, OFP_VERSION);
                buffer_delete(*msgp);
                *msgp = NULL;
                return EPROTO;
            }
        }
    }
    if (retval) {
        *msgp = NULL;
    }
    return retval;
}

/* Tries to queue 'msg' for transmission on 'vconn', which must be an active
 * vconn.  If successful, returns 0, in which case ownership of 'msg' is
 * transferred to the vconn.  Success does not guarantee that 'msg' has been or
 * ever will be delivered to the peer, only that it has been queued for
 * transmission.
 *
 * Returns a positive errno value on failure, in which case the caller
 * retains ownership of 'msg'.
 *
 * vconn_send will not block.  If 'msg' cannot be immediately accepted for
 * transmission, it returns EAGAIN immediately. */
int
vconn_send(struct vconn *vconn, struct buffer *msg)
{
    int retval = vconn_connect(vconn);
    if (!retval) {
        assert(msg->size >= sizeof(struct ofp_header));
        assert(((struct ofp_header *) msg->data)->length == htons(msg->size));
        if (!VLOG_IS_DBG_ENABLED()) { 
            retval = (vconn->class->send)(vconn, msg);
        } else {
            char *s = ofp_to_string(msg->data, msg->size, 1);
            retval = (vconn->class->send)(vconn, msg);
            if (retval != EAGAIN) {
                VLOG_DBG("sent (%s): %s", strerror(retval), s);
            }
            free(s);
        }
    }
    return retval;
}

/* Same as vconn_send, except that it waits until 'msg' can be transmitted. */
int
vconn_send_block(struct vconn *vconn, struct buffer *msg)
{
    int retval;
    while ((retval = vconn_send(vconn, msg)) == EAGAIN) {
        vconn_send_wait(vconn);
        VLOG_DBG("blocking on vconn send");
        poll_block();
    }
    return retval;
}

/* Same as vconn_recv, except that it waits until a message is received. */
int
vconn_recv_block(struct vconn *vconn, struct buffer **msgp)
{
    int retval;
    while ((retval = vconn_recv(vconn, msgp)) == EAGAIN) {
        vconn_recv_wait(vconn);
        VLOG_DBG("blocking on vconn receive");
        poll_block();
    }
    return retval;
}

/* Sends 'request' to 'vconn' and blocks until it receives a reply with a
 * matching transaction ID.  Returns 0 if successful, in which case the reply
 * is stored in '*replyp' for the caller to examine and free.  Otherwise
 * returns a positive errno value, or EOF, and sets '*replyp' to null.
 *
 * 'request' is always destroyed, regardless of the return value. */
int
vconn_transact(struct vconn *vconn, struct buffer *request,
               struct buffer **replyp)
{
    uint32_t send_xid = ((struct ofp_header *) request->data)->xid;
    int error;

    *replyp = NULL;
    error = vconn_send_block(vconn, request);
    if (error) {
        buffer_delete(request);
        return error;
    }
    for (;;) {
        uint32_t recv_xid;
        struct buffer *reply;

        error = vconn_recv_block(vconn, &reply);
        if (error) {
            return error;
        }
        recv_xid = ((struct ofp_header *) reply->data)->xid;
        if (send_xid == recv_xid) {
            *replyp = reply;
            return 0;
        }

        VLOG_DBG("received reply with xid %08"PRIx32" != expected %08"PRIx32,
                 recv_xid, send_xid);
        buffer_delete(reply);
    }
}

void
vconn_wait(struct vconn *vconn, enum vconn_wait_type wait)
{
    int connect_status;

    assert(vconn_is_passive(vconn)
           ? wait == WAIT_ACCEPT || wait == WAIT_CONNECT
           : wait == WAIT_CONNECT || wait == WAIT_RECV || wait == WAIT_SEND);

    connect_status = vconn_connect(vconn);
    if (connect_status) {
        if (connect_status == EAGAIN) {
            wait = WAIT_CONNECT;
        } else {
            poll_immediate_wake();
            return;
        }
    }

    (vconn->class->wait)(vconn, wait);
}

void
vconn_connect_wait(struct vconn *vconn)
{
    vconn_wait(vconn, WAIT_CONNECT);
}

void
vconn_accept_wait(struct vconn *vconn)
{
    vconn_wait(vconn, WAIT_ACCEPT);
}

void
vconn_recv_wait(struct vconn *vconn)
{
    vconn_wait(vconn, WAIT_RECV);
}

void
vconn_send_wait(struct vconn *vconn)
{
    vconn_wait(vconn, WAIT_SEND);
}

/* Allocates and returns the first byte of a buffer 'openflow_len' bytes long,
 * containing an OpenFlow header with the given 'type' and a random transaction
 * id.  Stores the new buffer in '*bufferp'.  The caller must free the buffer
 * when it is no longer needed. */
void *
make_openflow(size_t openflow_len, uint8_t type, struct buffer **bufferp) 
{
    return make_openflow_xid(openflow_len, type, random_uint32(), bufferp);
}

/* Allocates and returns the first byte of a buffer 'openflow_len' bytes long,
 * containing an OpenFlow header with the given 'type' and transaction id
 * 'xid'.  Stores the new buffer in '*bufferp'.  The caller must free the
 * buffer when it is no longer needed. */
void *
make_openflow_xid(size_t openflow_len, uint8_t type, uint32_t xid,
                  struct buffer **bufferp)
{
    struct buffer *buffer;
    struct ofp_header *oh;

    assert(openflow_len >= sizeof *oh);
    assert(openflow_len <= UINT16_MAX);
    buffer = *bufferp = buffer_new(openflow_len);
    oh = buffer_put_uninit(buffer, openflow_len);
    memset(oh, 0, openflow_len);
    oh->version = OFP_VERSION;
    oh->type = type;
    oh->length = htons(openflow_len);
    oh->xid = xid;
    return oh;
}

/* Updates the 'length' field of the OpenFlow message in 'buffer' to
 * 'buffer->size'. */
void
update_openflow_length(struct buffer *buffer) 
{
    struct ofp_header *oh = buffer_at_assert(buffer, 0, sizeof *oh);
    oh->length = htons(buffer->size); 
}

struct buffer *
make_add_flow(const struct flow *flow, uint32_t buffer_id, uint16_t max_idle,
              size_t n_actions)
{
    struct ofp_flow_mod *ofm;
    size_t size = sizeof *ofm + n_actions * sizeof ofm->actions[0];
    struct buffer *out = buffer_new(size);
    ofm = buffer_put_uninit(out, size);
    memset(ofm, 0, size);
    ofm->header.version = OFP_VERSION;
    ofm->header.type = OFPT_FLOW_MOD;
    ofm->header.length = htons(size);
    ofm->match.wildcards = htons(0);
    ofm->match.in_port = flow->in_port;
    memcpy(ofm->match.dl_src, flow->dl_src, sizeof ofm->match.dl_src);
    memcpy(ofm->match.dl_dst, flow->dl_dst, sizeof ofm->match.dl_dst);
    ofm->match.dl_vlan = flow->dl_vlan;
    ofm->match.dl_type = flow->dl_type;
    ofm->match.nw_src = flow->nw_src;
    ofm->match.nw_dst = flow->nw_dst;
    ofm->match.nw_proto = flow->nw_proto;
    ofm->match.tp_src = flow->tp_src;
    ofm->match.tp_dst = flow->tp_dst;
    ofm->command = htons(OFPFC_ADD);
    ofm->max_idle = htons(max_idle);
    ofm->buffer_id = htonl(buffer_id);
    return out;
}

struct buffer *
make_add_simple_flow(const struct flow *flow,
                     uint32_t buffer_id, uint16_t out_port, uint16_t max_idle)
{
    struct buffer *buffer = make_add_flow(flow, buffer_id, max_idle, 1);
    struct ofp_flow_mod *ofm = buffer->data;
    ofm->actions[0].type = htons(OFPAT_OUTPUT);
    ofm->actions[0].arg.output.max_len = htons(0);
    ofm->actions[0].arg.output.port = htons(out_port);
    return buffer;
}

struct buffer *
make_unbuffered_packet_out(const struct buffer *packet,
                           uint16_t in_port, uint16_t out_port)
{
    struct ofp_packet_out *opo;
    size_t size = sizeof *opo + packet->size;
    struct buffer *out = buffer_new(size);
    opo = buffer_put_uninit(out, size);
    memset(opo, 0, sizeof *opo);
    opo->header.version = OFP_VERSION;
    opo->header.type = OFPT_PACKET_OUT;
    opo->header.length = htons(size);
    opo->buffer_id = htonl(UINT32_MAX);
    opo->in_port = htons(in_port);
    opo->out_port = htons(out_port);
    memcpy(opo->u.data, packet->data, packet->size);
    return out;
}

struct buffer *
make_buffered_packet_out(uint32_t buffer_id,
                         uint16_t in_port, uint16_t out_port)
{
    struct ofp_packet_out *opo;
    size_t size = sizeof *opo + sizeof opo->u.actions[0];
    struct buffer *out = buffer_new(size);
    opo = buffer_put_uninit(out, size);
    memset(opo, 0, size);
    opo->header.version = OFP_VERSION;
    opo->header.type = OFPT_PACKET_OUT;
    opo->header.length = htons(size);
    opo->buffer_id = htonl(buffer_id);
    opo->in_port = htons(in_port);
    opo->out_port = htons(out_port);
    opo->u.actions[0].type = htons(OFPAT_OUTPUT);
    opo->u.actions[0].arg.output.max_len = htons(0);
    opo->u.actions[0].arg.output.port = htons(out_port);
    return out;
}

/* Creates and returns an OFPT_ECHO_REQUEST message with an empty payload. */
struct buffer *
make_echo_request(void)
{
    struct ofp_header *rq;
    struct buffer *out = buffer_new(sizeof *rq);
    rq = buffer_put_uninit(out, sizeof *rq);
    rq->version = OFP_VERSION;
    rq->type = OFPT_ECHO_REQUEST;
    rq->length = htons(sizeof *rq);
    rq->xid = 0;
    return out;
}

/* Creates and returns an OFPT_ECHO_REPLY message matching the
 * OFPT_ECHO_REQUEST message in 'rq'. */
struct buffer *
make_echo_reply(const struct ofp_header *rq)
{
    size_t size = ntohs(rq->length);
    struct buffer *out = buffer_new(size);
    struct ofp_header *reply = buffer_put(out, rq, size);
    reply->type = OFPT_ECHO_REPLY;
    return out;
}