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From: Laurent Vivier <lvivier@redhat.com>
To: David Gibson <david@gibson.dropbear.id.au>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v13 07/10] vhost-user: add vhost-user
Date: Wed, 20 Nov 2024 13:40:50 +0100	[thread overview]
Message-ID: <ae86d60b-766c-49e2-a83a-079f1aba7325@redhat.com> (raw)
In-Reply-To: <Zz1YkPwH9zU_7Xjl@zatzit>

On 20/11/2024 04:33, David Gibson wrote:
>> +	vu_set_vnethdr(vdev, flags_elem[0].in_sg[0].iov_base, 1);
>> +
>> +	eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
>> +
>> +	memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
>> +	memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
>> +
>> +	if (CONN_V4(conn)) {
>> +		struct tcp_payload_t *payload;
>> +		struct iphdr *iph;
>> +		uint32_t seq;
>> +
>> +		eh->h_proto = htons(ETH_P_IP);
>> +
>> +		iph = vu_ip(flags_elem[0].in_sg[0].iov_base);
>> +		*iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
>> +
>> +		payload = vu_payloadv4(flags_elem[0].in_sg[0].iov_base);
>> +		memset(&payload->th, 0, sizeof(payload->th));
>> +		payload->th.doff = offsetof(struct tcp_payload_t, data) / 4;
>> +		payload->th.ack = 1;
>> +
>> +		seq = conn->seq_to_tap;
>> +		ret = tcp_prepare_flags(c, conn, flags, &payload->th,
>> +					(struct tcp_syn_opts *)payload->data,
>> +					&optlen);
>> +		if (ret <= 0) {
>> +			vu_queue_rewind(vq, 1);
>> +			return ret;
>> +		}
>> +
>> +		l4len = tcp_fill_headers4(conn, NULL, iph, payload, optlen,
>> +					  NULL, seq, true);
>> +		l2len = sizeof(*iph);
> Much of the above duplicates tcp_vu_prepare().  Any chance you could
> call into it instead?

I tried but tcp_fill_headersX() needs the length computed in tcp_prepare_flags() but 
tcp_prepare_flags() needs to be after tcp_vu_prepare() because tcp_vu_prepare() resets the 
TCP header and tcp_prepare_flags() updates it with the flags.
tcp_prepare_flags() should be called in the middle of tcp_vu_prepare().
It's really simpler to duplicate the code of tcp_vu_prepare() in tcp_vu_send_flag() rather 
than to call tcp_vu_prepare() from tcp_vu_send_flag().

Thanks,
Laurent


  reply	other threads:[~2024-11-20 12:40 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-19 15:10 [PATCH v13 00/10] Add vhost-user support to passt. (part 3) Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 01/10] packet: replace struct desc by struct iovec Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 02/10] vhost-user: introduce virtio API Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 03/10] vhost-user: introduce vhost-user API Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 04/10] udp: Prepare udp.c to be shared with vhost-user Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 05/10] tcp: Export headers functions Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 06/10] passt: rename tap_sock_init() to tap_backend_init() Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 07/10] vhost-user: add vhost-user Laurent Vivier
2024-11-20  3:33   ` David Gibson
2024-11-20 12:40     ` Laurent Vivier [this message]
2024-11-21  4:20       ` David Gibson
2024-11-19 15:10 ` [PATCH v13 08/10] test: Add tests for passt in vhost-user mode Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 09/10] tcp_vu: Share more header construction between IPv4 and IPv6 paths Laurent Vivier
2024-11-19 15:10 ` [PATCH v13 10/10] tcp: Move tcp_l2_buf_fill_headers() to tcp_buf.c Laurent Vivier
2024-11-19 21:19 ` [PATCH v13 00/10] Add vhost-user support to passt. (part 3) Stefano Brivio
2024-11-20 11:35   ` Laurent Vivier

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