Re: [dpdk-dev] [dpdk-dev,2/3] pcap: add support for jumbo frames

[Maxim Uvarov <maxim.uvarov@linaro.org>]

Patch looks good for me. But in latest dpdk file path changed, but it 
applies with small reject.

Reviewed-by: Maxim Uvarov <maxim.uvarov@linaro.org>

Maxim.

On 02/27/15 16:42, Tero Aho wrote:
> Extend eth_pcap_rx and eth_pcap_tx to support jumbo frames.
> On receive side read large packets into multiple mbufs and
> on the transmit side do the opposite.
>
> Signed-off-by: Tero Aho <tero.aho@coriant.com>
>
> ---
> lib/librte_pmd_pcap/rte_eth_pcap.c | 88 ++++++++++++++++++++++++++++++++------
>   1 file changed, 75 insertions(+), 13 deletions(-)
>
> --
> 1.9.1
>
>
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> diff --git a/lib/librte_pmd_pcap/rte_eth_pcap.c b/lib/librte_pmd_pcap/rte_eth_pcap.c
> index 289af28..3f23f0a 100644
> --- a/lib/librte_pmd_pcap/rte_eth_pcap.c
> +++ b/lib/librte_pmd_pcap/rte_eth_pcap.c
> @@ -52,7 +52,7 @@
>   #include <pcap.h>
>
>   #define RTE_ETH_PCAP_SNAPSHOT_LEN 65535
> -#define RTE_ETH_PCAP_SNAPLEN 4096
> +#define RTE_ETH_PCAP_SNAPLEN ETHER_MAX_JUMBO_FRAME_LEN
>   #define RTE_ETH_PCAP_PROMISC 1
>   #define RTE_ETH_PCAP_TIMEOUT -1
>   #define ETH_PCAP_RX_PCAP_ARG  "rx_pcap"
> @@ -132,6 +132,43 @@ static struct rte_eth_link pmd_link = {
>                  .link_status = 0
>   };
>
> +/*
> + * Helper function to read mbuf chain.
> + */
> +static int
> +eth_pcap_rx_jumbo(struct rte_mempool *mb_pool,
> +                 struct rte_mbuf *mbuf,
> +                 const u_char *data,
> +                 uint16_t data_len)
> +{
> +       struct rte_mbuf *m = mbuf;
> +       /* copy first segment */
> +       uint16_t len = rte_pktmbuf_tailroom(mbuf);
> +       rte_memcpy(rte_pktmbuf_append(mbuf, len), data, len);
> +       data_len -= len;
> +       data += len;
> +
> +       while (data_len > 0) {
> +               /* allocate next mbuf and point to that */
> +               m->next = rte_pktmbuf_alloc(mb_pool);
> +               if (unlikely(m->next == NULL))
> +                       return -1;
> +               m = m->next;
> +
> +               /* no headroom needed in chained mbufs */
> +               rte_pktmbuf_prepend(m, rte_pktmbuf_headroom(m));
> +               m->data_len = m->pkt_len = 0;
> +
> +               /* copy next segment */
> +               len = RTE_MIN(rte_pktmbuf_tailroom(m), data_len);
> +               rte_memcpy(rte_pktmbuf_append(m, len), data, len);
> +
> +               mbuf->nb_segs++;
> +               data_len -= len;
> +               data += len;
> +       }
> +       return mbuf->nb_segs;
> +}
>
>   static uint16_t
>   eth_pcap_rx(void *queue,
> @@ -173,17 +210,18 @@ eth_pcap_rx(void *queue,
>                          rte_memcpy(rte_pktmbuf_mtod(mbuf, void *), packet,
>                                          header.len);
>                          mbuf->data_len = (uint16_t)header.len;
> -                       mbuf->pkt_len = mbuf->data_len;
> -                       mbuf->port = pcap_q->in_port;
> -                       bufs[num_rx] = mbuf;
> -                       num_rx++;
>                  } else {
> -                       /* pcap packet will not fit in the mbuf, so drop packet */
> -                       RTE_LOG(ERR, PMD,
> -                                       "PCAP packet %d bytes will not fit in mbuf (%d bytes)\n",
> -                                       header.len, buf_size);
> -                       rte_pktmbuf_free(mbuf);
> +                       /* pcap packet will not fit in a single mbuf */
> +                       if (unlikely(eth_pcap_rx_jumbo(pcap_q->mb_pool, mbuf,
> +                                       packet, header.len) == -1)) {
> +                               rte_pktmbuf_free(mbuf);
> +                               break;
> +                       }
>                  }
> +               mbuf->pkt_len = (uint16_t)header.len;
> +               mbuf->port = pcap_q->in_port;
> +               bufs[num_rx] = mbuf;
> +               num_rx++;
>          }
>          pcap_q->rx_pkts += num_rx;
>          return num_rx;
> @@ -241,6 +279,27 @@ eth_pcap_tx_dumper(void *queue,
>   }
>
>   /*
> + * Helper function to write mbuf chain.
> + */
> +static uint16_t
> +eth_pcap_tx_jumbo(pcap_t *pcap,
> +                 struct rte_mbuf *mbuf)
> +{
> +       u_char data[ETHER_MAX_JUMBO_FRAME_LEN];
> +       uint16_t data_len = 0;
> +
> +       while (mbuf != NULL) {
> +               /* There is no writev style function in libpcap, */
> +               /* we unfortunately have to copy data to a buffer. */
> +               rte_memcpy(data + data_len, rte_pktmbuf_mtod(mbuf, void *),
> +                          mbuf->data_len);
> +               data_len += mbuf->data_len;
> +               mbuf = mbuf->next;
> +       }
> +       return pcap_sendpacket(pcap, data, data_len);
> +}
> +
> +/*
>    * Callback to handle sending packets through a real NIC.
>    */
>   static uint16_t
> @@ -259,9 +318,12 @@ eth_pcap_tx(void *queue,
>
>          for (i = 0; i < nb_pkts; i++) {
>                  mbuf = bufs[i];
> -               ret = pcap_sendpacket(tx_queue->pcap,
> -                               rte_pktmbuf_mtod(mbuf, u_char *),
> -                               mbuf->data_len);
> +               if (likely(mbuf->nb_segs == 1))
> +                       ret = pcap_sendpacket(tx_queue->pcap,
> +                                             rte_pktmbuf_mtod(mbuf, u_char *),
> +                                             mbuf->data_len);
> +               else
> +                       ret = eth_pcap_tx_jumbo(tx_queue->pcap, mbuf);
>                  if (unlikely(ret != 0))
>                          break;
>                  num_tx++;