Re: [PATCH for 8.0] hw/net/net_tx_pkt: Align l3_hdr

[Akihiko Odaki <akihiko.odaki@daynix.com>]

Hi Jason,

I have sent some patches for igb and packet abstractions. They are fixes 
intended to be included in 8.0 so please have a look at them.

Regards,
Akihiko Odaki

On 2023/03/16 21:26, Akihiko Odaki wrote:
> Align the l3_hdr member of NetTxPkt by defining it as a union of
> ip_header, ip6_header, and an array of octets.
> 
> Fixes: e263cd49c7 ("Packet abstraction for VMWARE network devices")
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1544
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>   hw/net/net_tx_pkt.c | 21 +++++++++++----------
>   1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
> index efe80b1a80..8dc8568ba2 100644
> --- a/hw/net/net_tx_pkt.c
> +++ b/hw/net/net_tx_pkt.c
> @@ -43,7 +43,11 @@ struct NetTxPkt {
>       struct iovec *vec;
>   
>       uint8_t l2_hdr[ETH_MAX_L2_HDR_LEN];
> -    uint8_t l3_hdr[ETH_MAX_IP_DGRAM_LEN];
> +    union {
> +        struct ip_header ip;
> +        struct ip6_header ip6;
> +        uint8_t octets[ETH_MAX_IP_DGRAM_LEN];
> +    } l3_hdr;
>   
>       uint32_t payload_len;
>   
> @@ -89,16 +93,14 @@ void net_tx_pkt_update_ip_hdr_checksum(struct NetTxPkt *pkt)
>   {
>       uint16_t csum;
>       assert(pkt);
> -    struct ip_header *ip_hdr;
> -    ip_hdr = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
>   
> -    ip_hdr->ip_len = cpu_to_be16(pkt->payload_len +
> +    pkt->l3_hdr.ip.ip_len = cpu_to_be16(pkt->payload_len +
>           pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len);
>   
> -    ip_hdr->ip_sum = 0;
> -    csum = net_raw_checksum((uint8_t *)ip_hdr,
> +    pkt->l3_hdr.ip.ip_sum = 0;
> +    csum = net_raw_checksum(pkt->l3_hdr.octets,
>           pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len);
> -    ip_hdr->ip_sum = cpu_to_be16(csum);
> +    pkt->l3_hdr.ip.ip_sum = cpu_to_be16(csum);
>   }
>   
>   void net_tx_pkt_update_ip_checksums(struct NetTxPkt *pkt)
> @@ -832,15 +834,14 @@ void net_tx_pkt_fix_ip6_payload_len(struct NetTxPkt *pkt)
>   {
>       struct iovec *l2 = &pkt->vec[NET_TX_PKT_L2HDR_FRAG];
>       if (eth_get_l3_proto(l2, 1, l2->iov_len) == ETH_P_IPV6) {
> -        struct ip6_header *ip6 = (struct ip6_header *) pkt->l3_hdr;
>           /*
>            * TODO: if qemu would support >64K packets - add jumbo option check
>            * something like that:
>            * 'if (ip6->ip6_plen == 0 && !has_jumbo_option(ip6)) {'
>            */
> -        if (ip6->ip6_plen == 0) {
> +        if (pkt->l3_hdr.ip6.ip6_plen == 0) {
>               if (pkt->payload_len <= ETH_MAX_IP_DGRAM_LEN) {
> -                ip6->ip6_plen = htons(pkt->payload_len);
> +                pkt->l3_hdr.ip6.ip6_plen = htons(pkt->payload_len);
>               }
>               /*
>                * TODO: if qemu would support >64K packets