net_pkt: Name vmxnet3 packet abstractions more generic

This patch drops "vmx" prefix from packet abstractions names
to emphasize the fact they are generic and not tied to any
specific network device.

These abstractions will be reused by e1000e emulation implementation
introduced by following patches so their names need generalization.

This patch (except renamed files, adjusted comments and changes in MAINTAINTERS)
was produced by:

git grep -lz 'vmxnet_tx_pkt' | xargs -0 perl -i'' -pE "s/vmxnet_tx_pkt/net_tx_pkt/g"
git grep -lz 'vmxnet_rx_pkt' | xargs -0 perl -i'' -pE "s/vmxnet_rx_pkt/net_rx_pkt/g"
git grep -lz 'VmxnetTxPkt' | xargs -0 perl -i'' -pE "s/VmxnetTxPkt/NetTxPkt/g"
git grep -lz 'VMXNET_TX_PKT' | xargs -0 perl -i'' -pE "s/VMXNET_TX_PKT/NET_TX_PKT/g"
git grep -lz 'VmxnetRxPkt' | xargs -0 perl -i'' -pE "s/VmxnetRxPkt/NetRxPkt/g"
git grep -lz 'VMXNET_RX_PKT' | xargs -0 perl -i'' -pE "s/VMXNET_RX_PKT/NET_RX_PKT/g"
sed -ie 's/VMXNET_/NET_/g' hw/net/vmxnet_rx_pkt.c
sed -ie 's/VMXNET_/NET_/g' hw/net/vmxnet_tx_pkt.c

Signed-off-by: Dmitry Fleytman <dmitry.fleytman@ravellosystems.com>
Signed-off-by: Leonid Bloch <leonid.bloch@ravellosystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 581 insertions, 0 deletions

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
new file mode 100644
index 0000000000..94c7e3d3f6
--- /dev/null
+++ b/hw/net/net_tx_pkt.c
@@ -0,0 +1,581 @@
+/*
+ * QEMU 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 "qemu/osdep.h"
+#include "hw/hw.h"
+#include "net_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"
+
+enum {
+    NET_TX_PKT_VHDR_FRAG = 0,
+    NET_TX_PKT_L2HDR_FRAG,
+    NET_TX_PKT_L3HDR_FRAG,
+    NET_TX_PKT_PL_START_FRAG
+};
+
+/* TX packet private context */
+struct NetTxPkt {
+    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 net_tx_pkt_init(struct NetTxPkt **pkt, uint32_t max_frags,
+    bool has_virt_hdr)
+{
+    struct NetTxPkt *p = g_malloc0(sizeof *p);
+
+    p->vec = g_malloc((sizeof *p->vec) *
+        (max_frags + NET_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[NET_TX_PKT_VHDR_FRAG].iov_base = &p->virt_hdr;
+    p->vec[NET_TX_PKT_VHDR_FRAG].iov_len =
+        p->has_virt_hdr ? sizeof p->virt_hdr : 0;
+    p->vec[NET_TX_PKT_L2HDR_FRAG].iov_base = &p->l2_hdr;
+    p->vec[NET_TX_PKT_L3HDR_FRAG].iov_base = NULL;
+    p->vec[NET_TX_PKT_L3HDR_FRAG].iov_len = 0;
+
+    *pkt = p;
+}
+
+void net_tx_pkt_uninit(struct NetTxPkt *pkt)
+{
+    if (pkt) {
+        g_free(pkt->vec);
+        g_free(pkt->raw);
+        g_free(pkt);
+    }
+}
+
+void net_tx_pkt_update_ip_checksums(struct NetTxPkt *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[NET_TX_PKT_L3HDR_FRAG].iov_base;
+
+    if (pkt->payload_len + pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len >
+        ETH_MAX_IP_DGRAM_LEN) {
+        return;
+    }
+
+    ip_hdr->ip_len = cpu_to_be16(pkt->payload_len +
+        pkt->vec[NET_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[NET_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[NET_TX_PKT_PL_START_FRAG], pkt->payload_frags,
+                 pkt->virt_hdr.csum_offset, &csum, sizeof(csum));
+}
+
+static void net_tx_pkt_calculate_hdr_len(struct NetTxPkt *pkt)
+{
+    pkt->hdr_len = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len +
+        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len;
+}
+
+static bool net_tx_pkt_parse_headers(struct NetTxPkt *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[NET_TX_PKT_L2HDR_FRAG];
+    l3_hdr = &pkt->vec[NET_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 < sizeof(struct eth_header)) {
+        l2_hdr->iov_len = 0;
+        return false;
+    }
+
+    l2_hdr->iov_len = sizeof(struct eth_header);
+    switch (be16_to_cpu(PKT_GET_ETH_HDR(l2_hdr->iov_base)->h_proto)) {
+    case ETH_P_VLAN:
+        l2_hdr->iov_len += sizeof(struct vlan_header);
+        break;
+    case ETH_P_DVLAN:
+        l2_hdr->iov_len += 2 * sizeof(struct vlan_header);
+        break;
+    }
+
+    if (bytes_read < l2_hdr->iov_len) {
+        l2_hdr->iov_len = 0;
+        return false;
+    }
+
+    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;
+    }
+
+    net_tx_pkt_calculate_hdr_len(pkt);
+    pkt->packet_type = get_eth_packet_type(l2_hdr->iov_base);
+    return true;
+}
+
+static bool net_tx_pkt_rebuild_payload(struct NetTxPkt *pkt)
+{
+    size_t payload_len = iov_size(pkt->raw, pkt->raw_frags) - pkt->hdr_len;
+
+    pkt->payload_frags = iov_copy(&pkt->vec[NET_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 net_tx_pkt_parse(struct NetTxPkt *pkt)
+{
+    return net_tx_pkt_parse_headers(pkt) &&
+           net_tx_pkt_rebuild_payload(pkt);
+}
+
+struct virtio_net_hdr *net_tx_pkt_get_vhdr(struct NetTxPkt *pkt)
+{
+    assert(pkt);
+    return &pkt->virt_hdr;
+}
+
+static uint8_t net_tx_pkt_get_gso_type(struct NetTxPkt *pkt,
+                                          bool tso_enable)
+{
+    uint8_t rc = VIRTIO_NET_HDR_GSO_NONE;
+    uint16_t l3_proto;
+
+    l3_proto = eth_get_l3_proto(pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_base,
+        pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len);
+
+    if (!tso_enable) {
+        goto func_exit;
+    }
+
+    rc = eth_get_gso_type(l3_proto, pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base,
+                          pkt->l4proto);
+
+func_exit:
+    return rc;
+}
+
+void net_tx_pkt_build_vheader(struct NetTxPkt *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 = net_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[NET_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:
+        g_assert_not_reached();
+    }
+
+    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 net_tx_pkt_setup_vlan_header(struct NetTxPkt *pkt, uint16_t vlan)
+{
+    bool is_new;
+    assert(pkt);
+
+    eth_setup_vlan_headers(pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_base,
+        vlan, &is_new);
+
+    /* update l2hdrlen */
+    if (is_new) {
+        pkt->hdr_len += sizeof(struct vlan_header);
+        pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len +=
+            sizeof(struct vlan_header);
+    }
+}
+
+bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *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 net_tx_pkt_get_packet_type(struct NetTxPkt *pkt)
+{
+    assert(pkt);
+
+    return pkt->packet_type;
+}
+
+size_t net_tx_pkt_get_total_len(struct NetTxPkt *pkt)
+{
+    assert(pkt);
+
+    return pkt->hdr_len + pkt->payload_len;
+}
+
+void net_tx_pkt_dump(struct NetTxPkt *pkt)
+{
+#ifdef NET_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[NET_TX_PKT_L2HDR_FRAG].iov_len,
+        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len, pkt->payload_len);
+#endif
+}
+
+void net_tx_pkt_reset(struct NetTxPkt *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[NET_TX_PKT_L3HDR_FRAG].iov_base);
+    pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base = NULL;
+
+    assert(pkt->vec);
+    for (i = NET_TX_PKT_L2HDR_FRAG;
+         i < pkt->payload_frags + NET_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 net_tx_pkt_do_sw_csum(struct NetTxPkt *pkt)
+{
+    struct iovec *iov = &pkt->vec[NET_TX_PKT_L2HDR_FRAG];
+    uint32_t csum_cntr;
+    uint16_t csum = 0;
+    /* num of iovec without vhdr */
+    uint32_t iov_len = pkt->payload_frags + NET_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[NET_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 {
+    NET_TX_PKT_FRAGMENT_L2_HDR_POS = 0,
+    NET_TX_PKT_FRAGMENT_L3_HDR_POS,
+    NET_TX_PKT_FRAGMENT_HEADER_NUM
+};
+
+#define NET_MAX_FRAG_SG_LIST (64)
+
+static size_t net_tx_pkt_fetch_fragment(struct NetTxPkt *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 = NET_TX_PKT_FRAGMENT_HEADER_NUM;
+
+    while (fetched < pkt->virt_hdr.gso_size) {
+
+        /* no more place in fragment iov */
+        if (*dst_idx == NET_MAX_FRAG_SG_LIST) {
+            break;
+        }
+
+        /* no more data in iovec */
+        if (*src_idx == (pkt->payload_frags + NET_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 net_tx_pkt_do_sw_fragmentation(struct NetTxPkt *pkt,
+    NetClientState *nc)
+{
+    struct iovec fragment[NET_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 =  NET_TX_PKT_PL_START_FRAG, dst_idx;
+    size_t src_offset = 0;
+    size_t fragment_offset = 0;
+
+    l2_iov_base = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_base;
+    l2_iov_len = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len;
+    l3_iov_base = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
+    l3_iov_len = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len;
+
+    /* Copy headers */
+    fragment[NET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_base = l2_iov_base;
+    fragment[NET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_len = l2_iov_len;
+    fragment[NET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_base = l3_iov_base;
+    fragment[NET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_len = l3_iov_len;
+
+
+    /* Put as much data as possible and send */
+    do {
+        fragment_len = net_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 net_tx_pkt_send(struct NetTxPkt *pkt, NetClientState *nc)
+{
+    assert(pkt);
+
+    if (!pkt->has_virt_hdr &&
+        pkt->virt_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+        net_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[NET_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 + NET_TX_PKT_PL_START_FRAG);
+        return true;
+    }
+
+    return net_tx_pkt_do_sw_fragmentation(pkt, nc);
+}