From: David Gibson <david@gibson.dropbear.id.au>
To: Laurent Vivier <lvivier@redhat.com>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v4 1/8] pcap: add pcap_iov()
Date: Fri, 1 Mar 2024 10:16:39 +1100 [thread overview]
Message-ID: <ZeEQV52xmXiX7Pjy@zatzit> (raw)
In-Reply-To: <20240229165955.829476-2-lvivier@redhat.com>
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On Thu, Feb 29, 2024 at 05:59:48PM +0100, Laurent Vivier wrote:
> Introduce a new function pcap_iov() to capture packet desribed by an IO
> vector.
>
> Update pcap_frame() to manage iovcnt > 1.
Yikes. I hadn't actually realised my version only worked for iovcnt
== 1.
>
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>
> Notes:
> v4:
> - use pcap_frame()
>
> v3:
> - update rationale
> - update comment
> - use strerror(errno)
> - use size_t for io vector length
>
> v2:
> - introduce pcap_header(), a common helper to write
> packet header
> - use writev() rather than write() in a loop
> - add functions comment
>
> pcap.c | 26 ++++++++++++++++++++++----
> pcap.h | 1 +
> 2 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/pcap.c b/pcap.c
> index a4057b5f9c6a..372f02045262 100644
> --- a/pcap.c
> +++ b/pcap.c
> @@ -32,6 +32,7 @@
> #include "passt.h"
> #include "log.h"
> #include "pcap.h"
> +#include "iov.h"
>
> #define PCAP_VERSION_MINOR 4
>
> @@ -78,7 +79,7 @@ struct pcap_pkthdr {
> static void pcap_frame(const struct iovec *iov, size_t iovcnt,
> size_t offset, const struct timeval *tv)
> {
> - size_t len = iov->iov_len - offset;
> + size_t len = iov_size(iov, iovcnt) - offset;
> struct pcap_pkthdr h = {
> .tv_sec = tv->tv_sec,
> .tv_usec = tv->tv_usec,
> @@ -87,10 +88,8 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
> };
> struct iovec hiov = { &h, sizeof(h) };
>
> - (void)iovcnt;
> -
> if (write_remainder(pcap_fd, &hiov, 1, 0) < 0 ||
> - write_remainder(pcap_fd, iov, 1, offset) < 0) {
> + write_remainder(pcap_fd, iov, iovcnt, offset) < 0) {
> debug("Cannot log packet, length %zu: %s",
> len, strerror(errno));
> }
> @@ -135,6 +134,25 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
> pcap_frame(iov + i * frame_parts, frame_parts, offset, &tv);
> }
>
> +/*
> + * pcap_iov - Write packet data described by an I/O vector
> + * to a pcap file descriptor.
> + *
> + * @iov: Pointer to the array of struct iovec describing the I/O vector
> + * containing packet data to write, including L2 header
> + * @iovcnt: Number of buffers (@iov entries)
> + */
> +void pcap_iov(const struct iovec *iov, size_t iovcnt)
> +{
> + struct timeval tv;
> +
> + if (pcap_fd == -1)
> + return;
> +
> + gettimeofday(&tv, NULL);
> + pcap_frame(iov, iovcnt, 0, &tv);
> +}
> +
> /**
> * pcap_init() - Initialise pcap file
> * @c: Execution context
> diff --git a/pcap.h b/pcap.h
> index 85fc58e57572..b1c4c909c109 100644
> --- a/pcap.h
> +++ b/pcap.h
> @@ -9,6 +9,7 @@
> void pcap(const char *pkt, size_t len);
> void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
> size_t offset);
> +void pcap_iov(const struct iovec *iov, size_t n);
> void pcap_init(struct ctx *c);
>
> #endif /* PCAP_H */
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2024-02-29 23:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-29 16:59 [PATCH v4 0/8] Add vhost-user support to passt (part 1) Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 1/8] pcap: add pcap_iov() Laurent Vivier
2024-02-29 23:16 ` David Gibson [this message]
2024-02-29 16:59 ` [PATCH v4 2/8] checksum: align buffers Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 3/8] checksum: add csum_iov() Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 4/8] util: move IP stuff from util.[ch] to ip.[ch] Laurent Vivier
2024-02-29 23:19 ` David Gibson
2024-03-01 12:06 ` Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 5/8] checksum: use csum_ip4_header() in udp.c and tcp.c Laurent Vivier
2024-02-29 23:25 ` David Gibson
2024-03-01 12:31 ` Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 6/8] checksum: introduce functions to compute the header part checksum for TCP/UDP Laurent Vivier
2024-02-29 23:42 ` David Gibson
2024-02-29 16:59 ` [PATCH v4 7/8] tap: make tap_update_mac() generic Laurent Vivier
2024-02-29 16:59 ` [PATCH v4 8/8] tcp: Introduce ipv4_fill_headers()/ipv6_fill_headers() Laurent Vivier
2024-02-29 23:54 ` David Gibson
2024-03-03 13:50 ` Laurent Vivier
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