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/*

 * QEMU VMWARE VMXNET* paravirtual NICs - TX packets abstractions

 *

 * Copyright (c) 2012 Ravello Systems LTD (http://ravellosystems.com)

 *

 * Developed by Daynix Computing LTD (http://www.daynix.com)

 *

 * Authors:

 * Dmitry Fleytman <dmitry@daynix.com>

 * Tamir Shomer <tamirs@daynix.com>

 * Yan Vugenfirer <yan@daynix.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2 or later.

 * See the COPYING file in the top-level directory.

 *

 */

#include "vmxnet_tx_pkt.h"

#include "net/eth.h"

#include "qemu-common.h"

#include "qemu/iov.h"

#include "net/checksum.h"

#include "net/tap.h"

#include "net/net.h"

#include "exec/cpu-common.h"

enum {

    VMXNET_TX_PKT_VHDR_FRAG = 0,

    VMXNET_TX_PKT_L2HDR_FRAG,

    VMXNET_TX_PKT_L3HDR_FRAG,

    VMXNET_TX_PKT_PL_START_FRAG

};

/* TX packet private context */

struct VmxnetTxPkt {

    struct virtio_net_hdr virt_hdr;

    bool has_virt_hdr;

    struct iovec *raw;

    uint32_t raw_frags;

    uint32_t max_raw_frags;

    struct iovec *vec;

    uint8_t l2_hdr[ETH_MAX_L2_HDR_LEN];

    uint32_t payload_len;

    uint32_t payload_frags;

    uint32_t max_payload_frags;

    uint16_t hdr_len;

    eth_pkt_types_e packet_type;

    uint8_t l4proto;

};

void vmxnet_tx_pkt_init(struct VmxnetTxPkt **pkt, uint32_t max_frags,

    bool has_virt_hdr)

{

    struct VmxnetTxPkt *p = g_malloc0(sizeof *p);

    p->vec = g_malloc((sizeof *p->vec) *

        (max_frags + VMXNET_TX_PKT_PL_START_FRAG));

    p->raw = g_malloc((sizeof *p->raw) * max_frags);

    p->max_payload_frags = max_frags;

    p->max_raw_frags = max_frags;

    p->has_virt_hdr = has_virt_hdr;

    p->vec[VMXNET_TX_PKT_VHDR_FRAG].iov_base = &p->virt_hdr;

    p->vec[VMXNET_TX_PKT_VHDR_FRAG].iov_len =

        p->has_virt_hdr ? sizeof p->virt_hdr : 0;

    p->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_base = &p->l2_hdr;

    p->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base = NULL;

    p->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len = 0;

    *pkt = p;

}

void vmxnet_tx_pkt_uninit(struct VmxnetTxPkt *pkt)

{

    if (pkt) {

        g_free(pkt->vec);

        g_free(pkt->raw);

        g_free(pkt);

    }

}

void vmxnet_tx_pkt_update_ip_checksums(struct VmxnetTxPkt *pkt)

{

    uint16_t csum;

    uint32_t ph_raw_csum;

    assert(pkt);

    uint8_t gso_type = pkt->virt_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN;

    struct ip_header *ip_hdr;

    if (VIRTIO_NET_HDR_GSO_TCPV4 != gso_type &&

        VIRTIO_NET_HDR_GSO_UDP != gso_type) {

        return;

    }

    ip_hdr = pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base;

    if (pkt->payload_len + pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len >

        ETH_MAX_IP_DGRAM_LEN) {

        return;

    }

    ip_hdr->ip_len = cpu_to_be16(pkt->payload_len +

        pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len);

    /* Calculate IP header checksum                    */

    ip_hdr->ip_sum = 0;

    csum = net_raw_checksum((uint8_t *)ip_hdr,

        pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len);

    ip_hdr->ip_sum = cpu_to_be16(csum);

    /* Calculate IP pseudo header checksum             */

    ph_raw_csum = eth_calc_pseudo_hdr_csum(ip_hdr, pkt->payload_len);

    csum = cpu_to_be16(~net_checksum_finish(ph_raw_csum));

    iov_from_buf(&pkt->vec[VMXNET_TX_PKT_PL_START_FRAG], pkt->payload_frags,

                 pkt->virt_hdr.csum_offset, &csum, sizeof(csum));

}

static void vmxnet_tx_pkt_calculate_hdr_len(struct VmxnetTxPkt *pkt)

{

    pkt->hdr_len = pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_len +

        pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len;

}

static bool vmxnet_tx_pkt_parse_headers(struct VmxnetTxPkt *pkt)

{

    struct iovec *l2_hdr, *l3_hdr;

    size_t bytes_read;

    size_t full_ip6hdr_len;

    uint16_t l3_proto;

    assert(pkt);

    l2_hdr = &pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG];

    l3_hdr = &pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG];

    bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, 0, l2_hdr->iov_base,

                            ETH_MAX_L2_HDR_LEN);

    if (bytes_read < ETH_MAX_L2_HDR_LEN) {

        l2_hdr->iov_len = 0;

        return false;

    } else {

        l2_hdr->iov_len = eth_get_l2_hdr_length(l2_hdr->iov_base);

    }

    l3_proto = eth_get_l3_proto(l2_hdr->iov_base, l2_hdr->iov_len);

    switch (l3_proto) {

    case ETH_P_IP:

        l3_hdr->iov_base = g_malloc(ETH_MAX_IP4_HDR_LEN);

        bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,

                                l3_hdr->iov_base, sizeof(struct ip_header));

        if (bytes_read < sizeof(struct ip_header)) {

            l3_hdr->iov_len = 0;

            return false;

        }

        l3_hdr->iov_len = IP_HDR_GET_LEN(l3_hdr->iov_base);

        pkt->l4proto = ((struct ip_header *) l3_hdr->iov_base)->ip_p;

        /* copy optional IPv4 header data */

        bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags,

                                l2_hdr->iov_len + sizeof(struct ip_header),

                                l3_hdr->iov_base + sizeof(struct ip_header),

                                l3_hdr->iov_len - sizeof(struct ip_header));

        if (bytes_read < l3_hdr->iov_len - sizeof(struct ip_header)) {

            l3_hdr->iov_len = 0;

            return false;

        }

        break;

    case ETH_P_IPV6:

        if (!eth_parse_ipv6_hdr(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,

                               &pkt->l4proto, &full_ip6hdr_len)) {

            l3_hdr->iov_len = 0;

            return false;

        }

        l3_hdr->iov_base = g_malloc(full_ip6hdr_len);

        bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,

                                l3_hdr->iov_base, full_ip6hdr_len);

        if (bytes_read < full_ip6hdr_len) {

            l3_hdr->iov_len = 0;

            return false;

        } else {

            l3_hdr->iov_len = full_ip6hdr_len;

        }

        break;

    default:

        l3_hdr->iov_len = 0;

        break;

    }

    vmxnet_tx_pkt_calculate_hdr_len(pkt);

    pkt->packet_type = get_eth_packet_type(l2_hdr->iov_base);

    return true;

}

static bool vmxnet_tx_pkt_rebuild_payload(struct VmxnetTxPkt *pkt)

{

    size_t payload_len = iov_size(pkt->raw, pkt->raw_frags) - pkt->hdr_len;

    pkt->payload_frags = iov_copy(&pkt->vec[VMXNET_TX_PKT_PL_START_FRAG],

                                pkt->max_payload_frags,

                                pkt->raw, pkt->raw_frags,

                                pkt->hdr_len, payload_len);

    if (pkt->payload_frags != (uint32_t) -1) {

        pkt->payload_len = payload_len;

        return true;

    } else {

        return false;

    }

}

bool vmxnet_tx_pkt_parse(struct VmxnetTxPkt *pkt)

{

    return vmxnet_tx_pkt_parse_headers(pkt) &&

           vmxnet_tx_pkt_rebuild_payload(pkt);

}

struct virtio_net_hdr *vmxnet_tx_pkt_get_vhdr(struct VmxnetTxPkt *pkt)

{

    assert(pkt);

    return &pkt->virt_hdr;

}

static uint8_t vmxnet_tx_pkt_get_gso_type(struct VmxnetTxPkt *pkt,

                                          bool tso_enable)

{

    uint8_t rc = VIRTIO_NET_HDR_GSO_NONE;

    uint16_t l3_proto;

    l3_proto = eth_get_l3_proto(pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_base,

        pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_len);

    if (!tso_enable) {

        goto func_exit;

    }

    rc = eth_get_gso_type(l3_proto, pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base,

                          pkt->l4proto);

func_exit:

    return rc;

}

void vmxnet_tx_pkt_build_vheader(struct VmxnetTxPkt *pkt, bool tso_enable,

    bool csum_enable, uint32_t gso_size)

{

    struct tcp_hdr l4hdr;

    assert(pkt);

    /* csum has to be enabled if tso is. */

    assert(csum_enable || !tso_enable);

    pkt->virt_hdr.gso_type = vmxnet_tx_pkt_get_gso_type(pkt, tso_enable);

    switch (pkt->virt_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {

    case VIRTIO_NET_HDR_GSO_NONE:

        pkt->virt_hdr.hdr_len = 0;

        pkt->virt_hdr.gso_size = 0;

        break;

    case VIRTIO_NET_HDR_GSO_UDP:

        pkt->virt_hdr.gso_size = IP_FRAG_ALIGN_SIZE(gso_size);

        pkt->virt_hdr.hdr_len = pkt->hdr_len + sizeof(struct udp_header);

        break;

    case VIRTIO_NET_HDR_GSO_TCPV4:

    case VIRTIO_NET_HDR_GSO_TCPV6:

        iov_to_buf(&pkt->vec[VMXNET_TX_PKT_PL_START_FRAG], pkt->payload_frags,

                   0, &l4hdr, sizeof(l4hdr));

        pkt->virt_hdr.hdr_len = pkt->hdr_len + l4hdr.th_off * sizeof(uint32_t);

        pkt->virt_hdr.gso_size = IP_FRAG_ALIGN_SIZE(gso_size);

        break;

    default:

        assert(false);

    }

    if (csum_enable) {

        switch (pkt->l4proto) {

        case IP_PROTO_TCP:

            pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;

            pkt->virt_hdr.csum_start = pkt->hdr_len;

            pkt->virt_hdr.csum_offset = offsetof(struct tcp_hdr, th_sum);

            break;

        case IP_PROTO_UDP:

            pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;

            pkt->virt_hdr.csum_start = pkt->hdr_len;

            pkt->virt_hdr.csum_offset = offsetof(struct udp_hdr, uh_sum);

            break;

        default:

            break;

        }

    }

}

void vmxnet_tx_pkt_setup_vlan_header(struct VmxnetTxPkt *pkt, uint16_t vlan)

{

    bool is_new;

    assert(pkt);

    eth_setup_vlan_headers(pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_base,

        vlan, &is_new);

    /* update l2hdrlen */

    if (is_new) {

        pkt->hdr_len += sizeof(struct vlan_header);

        pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_len +=

            sizeof(struct vlan_header);

    }

}

bool vmxnet_tx_pkt_add_raw_fragment(struct VmxnetTxPkt *pkt, hwaddr pa,

    size_t len)

{

    hwaddr mapped_len = 0;

    struct iovec *ventry;

    assert(pkt);

    assert(pkt->max_raw_frags > pkt->raw_frags);

    if (!len) {

        return true;

     }

    ventry = &pkt->raw[pkt->raw_frags];

    mapped_len = len;

    ventry->iov_base = cpu_physical_memory_map(pa, &mapped_len, false);

    ventry->iov_len = mapped_len;

    pkt->raw_frags += !!ventry->iov_base;

    if ((ventry->iov_base == NULL) || (len != mapped_len)) {

        return false;

    }

    return true;

}

eth_pkt_types_e vmxnet_tx_pkt_get_packet_type(struct VmxnetTxPkt *pkt)

{

    assert(pkt);

    return pkt->packet_type;

}

size_t vmxnet_tx_pkt_get_total_len(struct VmxnetTxPkt *pkt)

{

    assert(pkt);

    return pkt->hdr_len + pkt->payload_len;

}

void vmxnet_tx_pkt_dump(struct VmxnetTxPkt *pkt)

{

#ifdef VMXNET_TX_PKT_DEBUG

    assert(pkt);

    printf("TX PKT: hdr_len: %d, pkt_type: 0x%X, l2hdr_len: %lu, "

        "l3hdr_len: %lu, payload_len: %u\n", pkt->hdr_len, pkt->packet_type,

        pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_len,

        pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len, pkt->payload_len);

#endif

}

void vmxnet_tx_pkt_reset(struct VmxnetTxPkt *pkt)

{

    int i;

    /* no assert, as reset can be called before tx_pkt_init */

    if (!pkt) {

        return;

    }

    memset(&pkt->virt_hdr, 0, sizeof(pkt->virt_hdr));

    g_free(pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base);

    pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base = NULL;

    assert(pkt->vec);

    for (i = VMXNET_TX_PKT_L2HDR_FRAG;

         i < pkt->payload_frags + VMXNET_TX_PKT_PL_START_FRAG; i++) {

        pkt->vec[i].iov_len = 0;

    }

    pkt->payload_len = 0;

    pkt->payload_frags = 0;

    assert(pkt->raw);

    for (i = 0; i < pkt->raw_frags; i++) {

        assert(pkt->raw[i].iov_base);

        cpu_physical_memory_unmap(pkt->raw[i].iov_base, pkt->raw[i].iov_len,

                                  false, pkt->raw[i].iov_len);

        pkt->raw[i].iov_len = 0;

    }

    pkt->raw_frags = 0;

    pkt->hdr_len = 0;

    pkt->packet_type = 0;

    pkt->l4proto = 0;

}

static void vmxnet_tx_pkt_do_sw_csum(struct VmxnetTxPkt *pkt)

{

    struct iovec *iov = &pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG];

    uint32_t csum_cntr;

    uint16_t csum = 0;

    /* num of iovec without vhdr */

    uint32_t iov_len = pkt->payload_frags + VMXNET_TX_PKT_PL_START_FRAG - 1;

    uint16_t csl;

    struct ip_header *iphdr;

    size_t csum_offset = pkt->virt_hdr.csum_start + pkt->virt_hdr.csum_offset;

    /* Put zero to checksum field */

    iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum);

    /* Calculate L4 TCP/UDP checksum */

    csl = pkt->payload_len;

    /* data checksum */

    csum_cntr =

        net_checksum_add_iov(iov, iov_len, pkt->virt_hdr.csum_start, csl);

    /* add pseudo header to csum */

    iphdr = pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base;

    csum_cntr += eth_calc_pseudo_hdr_csum(iphdr, csl);

    /* Put the checksum obtained into the packet */

    csum = cpu_to_be16(net_checksum_finish(csum_cntr));

    iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum);

}

enum {

    VMXNET_TX_PKT_FRAGMENT_L2_HDR_POS = 0,

    VMXNET_TX_PKT_FRAGMENT_L3_HDR_POS,

    VMXNET_TX_PKT_FRAGMENT_HEADER_NUM

};

#define VMXNET_MAX_FRAG_SG_LIST (64)

static size_t vmxnet_tx_pkt_fetch_fragment(struct VmxnetTxPkt *pkt,

    int *src_idx, size_t *src_offset, struct iovec *dst, int *dst_idx)

{

    size_t fetched = 0;

    struct iovec *src = pkt->vec;

    *dst_idx = VMXNET_TX_PKT_FRAGMENT_HEADER_NUM;

    while (fetched < pkt->virt_hdr.gso_size) {

        /* no more place in fragment iov */

        if (*dst_idx == VMXNET_MAX_FRAG_SG_LIST) {

            break;

        }

        /* no more data in iovec */

        if (*src_idx == (pkt->payload_frags + VMXNET_TX_PKT_PL_START_FRAG)) {

            break;

        }

        dst[*dst_idx].iov_base = src[*src_idx].iov_base + *src_offset;

        dst[*dst_idx].iov_len = MIN(src[*src_idx].iov_len - *src_offset,

            pkt->virt_hdr.gso_size - fetched);

        *src_offset += dst[*dst_idx].iov_len;

        fetched += dst[*dst_idx].iov_len;

        if (*src_offset == src[*src_idx].iov_len) {

            *src_offset = 0;

            (*src_idx)++;

        }

        (*dst_idx)++;

    }

    return fetched;

}

static bool vmxnet_tx_pkt_do_sw_fragmentation(struct VmxnetTxPkt *pkt,

    NetClientState *nc)

{

    struct iovec fragment[VMXNET_MAX_FRAG_SG_LIST];

    size_t fragment_len = 0;

    bool more_frags = false;

    /* some pointers for shorter code */

    void *l2_iov_base, *l3_iov_base;

    size_t l2_iov_len, l3_iov_len;

    int src_idx =  VMXNET_TX_PKT_PL_START_FRAG, dst_idx;

    size_t src_offset = 0;

    size_t fragment_offset = 0;

    l2_iov_base = pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_base;

    l2_iov_len = pkt->vec[VMXNET_TX_PKT_L2HDR_FRAG].iov_len;

    l3_iov_base = pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_base;

    l3_iov_len = pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len;

    /* Copy headers */

    fragment[VMXNET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_base = l2_iov_base;

    fragment[VMXNET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_len = l2_iov_len;

    fragment[VMXNET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_base = l3_iov_base;

    fragment[VMXNET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_len = l3_iov_len;

    /* Put as much data as possible and send */

    do {

        fragment_len = vmxnet_tx_pkt_fetch_fragment(pkt, &src_idx, &src_offset,

            fragment, &dst_idx);

        more_frags = (fragment_offset + fragment_len < pkt->payload_len);

        eth_setup_ip4_fragmentation(l2_iov_base, l2_iov_len, l3_iov_base,

            l3_iov_len, fragment_len, fragment_offset, more_frags);

        eth_fix_ip4_checksum(l3_iov_base, l3_iov_len);

        qemu_sendv_packet(nc, fragment, dst_idx);

        fragment_offset += fragment_len;

    } while (more_frags);

    return true;

}

bool vmxnet_tx_pkt_send(struct VmxnetTxPkt *pkt, NetClientState *nc)

{

    assert(pkt);

    if (!pkt->has_virt_hdr &&

        pkt->virt_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {

        vmxnet_tx_pkt_do_sw_csum(pkt);

    }

    /*

     * Since underlying infrastructure does not support IP datagrams longer

     * than 64K we should drop such packets and don't even try to send

     */

    if (VIRTIO_NET_HDR_GSO_NONE != pkt->virt_hdr.gso_type) {

        if (pkt->payload_len >

            ETH_MAX_IP_DGRAM_LEN -

            pkt->vec[VMXNET_TX_PKT_L3HDR_FRAG].iov_len) {

            return false;

        }

    }

    if (pkt->has_virt_hdr ||

        pkt->virt_hdr.gso_type == VIRTIO_NET_HDR_GSO_NONE) {

        qemu_sendv_packet(nc, pkt->vec,

            pkt->payload_frags + VMXNET_TX_PKT_PL_START_FRAG);

        return true;

    }

    return vmxnet_tx_pkt_do_sw_fragmentation(pkt, nc);

}