/*
 * Copyright (c) 2020 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.
 */

/**
 * @file base.c
 * #brief Implementation of base IO functions.
 */

#include <hicn/util/log.h>

#include "base.h"

/**
 * @brief Helper function for listener to read a single packet on a socket
 */
ssize_t io_read_single_fd(int fd, msgbuf_t * msgbuf, address_t * address)
{
    uint8_t * packet = msgbuf_get_packet(msgbuf);
    size_t size = msgbuf_get_len(msgbuf);

    for(;;) {
        ssize_t n = read(fd, packet, size);
        if (n == 0)
            return n;
        if (n < 0) {
            if (errno == EINTR)
                continue; // XXX was break;
            ERROR("read failed %d: (%d) %s", fd, errno, strerror(errno));
            return -1;
        }

        msgbuf->length = n;
        *address = ADDRESS_ANY(AF_UNSPEC, 0); // XXX placeholder, see hicn.c
    }

    return 1;
}

ssize_t io_read_single_socket(int fd, msgbuf_t * msgbuf, address_t * address)
{

    struct sockaddr_storage * sa = (struct sockaddr_storage *)address;
    socklen_t sa_len = sizeof(sa);

    uint8_t * packet = msgbuf_get_packet(msgbuf);

    for (;;) {
        ssize_t n = recvfrom(fd, packet, MTU, 0, (struct sockaddr *)&sa, &sa_len);
        if (n == 0)
            return n;
        if (n < 0) {
            if (errno == EINTR)
                continue; // XXX was break;
            ERROR("recvfrom failed %d: (%d) %s", fd, errno, strerror(errno));
            return -1;
        }

        msgbuf->length = n;
    }

    return 1;
}

#ifdef __linux__
ssize_t io_read_batch_socket(int fd, msgbuf_t ** msgbuf,
        address_t ** address, size_t batch_size)
{
    struct mmsghdr msghdr[batch_size];
    struct iovec iovecs[batch_size];
    struct sockaddr_storage addrs[batch_size];

    /* Prepare the mmghdr struct for recvmmsg */
    for (unsigned i = 0; i < MAX_MSG; i++) {
         struct mmsghdr *msg = &msghdr[i];
        *msg = (struct mmsghdr) {
            .msg_hdr = {
                .msg_iov = &iovecs[i],
                .msg_iovlen = 1,
                .msg_name = &addrs[i],
                .msg_namelen = sizeof(struct sockaddr_storage),
                .msg_control = NULL,
                .msg_controllen = 0,
            },
        };

        iovecs[i] = (struct iovec) {
            .iov_base = msgbuf_get_packet(msgbuf[i]),
            .iov_len = MTU,
        };
    }

    int n;
    for (;;) {
        n = recvmmsg(fd, msghdr, batch_size, /* flags */ 0,
                /* timeout */ NULL);
        if (n == 0)
            return 0;
        if (n < 0) {
            if (errno == EINTR)
                continue; // XXX was break;
            ERROR("read failed %d: (%d) %s", fd, errno, strerror(errno));
            return (ssize_t) n;
        }

        /* Assign size to msgbuf, and build address pair */
        for (int i = 0; i < n; i++) {
            struct mmsghdr *msg = &msghdr[i];
            msgbuf[i]->length = msg->msg_hdr.msg_iovlen;
            **address = *(address_t*)msg->msg_hdr.msg_name;
        }
    }

    return n;
}
#endif /* __linux__ */