Re: [dpdk-dev] [PATCH v4] examples/l3fwd: ipv4 and udp/tcp cksum verification through software

["Walsh, Conor" <conor.walsh@intel.com>]

> From: dev <dev-bounces@dpdk.org> On Behalf Of Usama Nadeem
> Sent: Thursday 14 October 2021 19:43
> To: thomas@monjalon.net
> Cc: dev@dpdk.org; Usama Nadeem <usama.nadeem@emumba.com>
> Subject: [dpdk-dev] [PATCH v4] examples/l3fwd: ipv4 and udp/tcp cksum
> verification through software
> 
> checks if ipv4 and udptcp cksum offload capability available
> If not available, cksum is verified through software
> If cksum is corrupt, packet is dropped, rest of the packets
> are forwarded back.
> 
> Bugzilla ID:545
> Signed-off-by: Usama Nadeem <usama.nadeem@emumba.com>
> ---

Hi Usama,

This should be done in a generic way that allows all the lookup methods to support it not just LPM.
check_software_cksum should go in a common file and be called from LPM, FIB and possibly EM.

Thanks,
Conor.

>  examples/l3fwd/l3fwd.h     |  6 ++++
>  examples/l3fwd/l3fwd_lpm.c | 72
> ++++++++++++++++++++++++++++++++++++--
>  examples/l3fwd/main.c      | 33 +++++++++++++++--
>  3 files changed, 105 insertions(+), 6 deletions(-)
> 
> diff --git a/examples/l3fwd/l3fwd.h b/examples/l3fwd/l3fwd.h
> index a808d60247..c2c21a91fb 100644
> --- a/examples/l3fwd/l3fwd.h
> +++ b/examples/l3fwd/l3fwd.h
> @@ -55,6 +55,8 @@
>  #define L3FWD_HASH_ENTRIES		(1024*1024*1)
>  #endif
>  #define HASH_ENTRY_NUMBER_DEFAULT	4
> +extern bool l3_sft_cksum;
> +extern bool l4_sft_cksum;
> 
>  struct mbuf_table {
>  	uint16_t len;
> @@ -210,6 +212,10 @@ em_main_loop(__rte_unused void *dummy);
>  int
>  lpm_main_loop(__rte_unused void *dummy);
> 
> +int
> +check_software_cksum(struct rte_mbuf **pkts_burst,
> +struct rte_mbuf **pkts_burst_to_send, int nb_rx);
> +
>  int
>  fib_main_loop(__rte_unused void *dummy);
> 
> diff --git a/examples/l3fwd/l3fwd_lpm.c b/examples/l3fwd/l3fwd_lpm.c
> index 232b606b54..ecaf323943 100644
> --- a/examples/l3fwd/l3fwd_lpm.c
> +++ b/examples/l3fwd/l3fwd_lpm.c
> @@ -26,6 +26,7 @@
>  #include <rte_udp.h>
>  #include <rte_lpm.h>
>  #include <rte_lpm6.h>
> +#include <rte_net.h>
> 
>  #include "l3fwd.h"
>  #include "l3fwd_event.h"
> @@ -139,16 +140,65 @@ lpm_get_dst_port_with_ipv4(const struct
> lcore_conf *qconf, struct rte_mbuf *pkt,
>  #include "l3fwd_lpm.h"
>  #endif
> 
> +
> +int check_software_cksum(struct rte_mbuf **pkts_burst,
> +struct rte_mbuf **pkts_burst_to_send, int nb_rx)
> +{
> +	int j;
> +	int i = 0;
> +	struct rte_net_hdr_lens hdr_lens;
> +	struct rte_ipv4_hdr *ipv4_hdr;
> +	void *l3_hdr;
> +	void *l4_hdr;
> +	rte_be16_t prev_cksum;
> +	int dropped_pkts_udp_tcp = 0;
> +	int dropped_pkts_ipv4 = 0;
> +	bool dropped;
> +	for (j = 0; j < nb_rx; j++) {
> +		dropped = false;
> +		rte_net_get_ptype(pkts_burst[j], &hdr_lens,
> RTE_PTYPE_ALL_MASK);
> +		l3_hdr = rte_pktmbuf_mtod_offset(pkts_burst[j],
> +		void *, hdr_lens.l2_len);
> +		l4_hdr = rte_pktmbuf_mtod_offset(pkts_burst[j],
> +		void *, hdr_lens.l2_len + hdr_lens.l3_len);
> +		ipv4_hdr = l3_hdr;
> +		prev_cksum = ipv4_hdr->hdr_checksum;
> +		ipv4_hdr->hdr_checksum = 0;
> +		ipv4_hdr->hdr_checksum = rte_ipv4_cksum(ipv4_hdr);
> +
> +		if (l3_sft_cksum && prev_cksum != ipv4_hdr-
> >hdr_checksum) {
> +			rte_pktmbuf_free(pkts_burst[j]);
> +			dropped_pkts_ipv4++;
> +			dropped = true;
> +		} else if (l4_sft_cksum &&
> +				rte_ipv4_udptcp_cksum_verify
> +				(l3_hdr, l4_hdr) != 0) {
> +
> +			rte_pktmbuf_free(pkts_burst[j]);
> +			dropped_pkts_udp_tcp++;
> +			dropped = true;
> +		}
> +		if (dropped == false) {
> +			pkts_burst_to_send[i] = pkts_burst[j];
> +			i++;
> +		}
> +
> +	}
> +	return dropped_pkts_udp_tcp+dropped_pkts_ipv4;
> +}
> +
>  /* main processing loop */
>  int
>  lpm_main_loop(__rte_unused void *dummy)
>  {
>  	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
> +	struct rte_mbuf *pkts_burst_to_send[MAX_PKT_BURST];
>  	unsigned lcore_id;
>  	uint64_t prev_tsc, diff_tsc, cur_tsc;
>  	int i, nb_rx;
>  	uint16_t portid;
>  	uint8_t queueid;
> +	int dropped;
>  	struct lcore_conf *qconf;
>  	const uint64_t drain_tsc = (rte_get_tsc_hz() + US_PER_S - 1) /
>  		US_PER_S * BURST_TX_DRAIN_US;
> @@ -209,19 +259,35 @@ lpm_main_loop(__rte_unused void *dummy)
>  			if (nb_rx == 0)
>  				continue;
> 
> +			if (l3_sft_cksum || l4_sft_cksum) {
> +				dropped =
> check_software_cksum(pkts_burst,
> +				pkts_burst_to_send,	nb_rx);
> +
> +				nb_rx = nb_rx-dropped;
> +			}
> +
> +
>  #if defined RTE_ARCH_X86 || defined __ARM_NEON \
>  			 || defined RTE_ARCH_PPC_64
> +		if (l3_sft_cksum == false && l4_sft_cksum == false)
>  			l3fwd_lpm_send_packets(nb_rx, pkts_burst,
>  						portid, qconf);
> +		else
> +			l3fwd_lpm_send_packets(nb_rx,
> pkts_burst_to_send,
> +						portid, qconf);
> +
>  #else
> -			l3fwd_lpm_no_opt_send_packets(nb_rx,
> pkts_burst,
> +			if (l3_sft_cksum == false && l4_sft_cksum == false)
> +				l3fwd_lpm_no_opt_send_packets(nb_rx,
> pkts_burst,
>  							portid, qconf);
> +			else
> +				l3fwd_lpm_no_opt_send_packets(nb_rx,
> +				pkts_burst_to_send, portid, qconf);
> +
>  #endif /* X86 */
>  		}
> -
>  		cur_tsc = rte_rdtsc();
>  	}
> -
>  	return 0;
>  }
> 
> diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c
> index 00ac267af1..a54aca070d 100644
> --- a/examples/l3fwd/main.c
> +++ b/examples/l3fwd/main.c
> @@ -61,6 +61,9 @@ static uint16_t nb_txd = RTE_TEST_TX_DESC_DEFAULT;
>  /**< Ports set in promiscuous mode off by default. */
>  static int promiscuous_on;
> 
> +bool l3_sft_cksum;
> +bool l4_sft_cksum;
> +
>  /* Select Longest-Prefix, Exact match or Forwarding Information Base. */
>  enum L3FWD_LOOKUP_MODE {
>  	L3FWD_LOOKUP_DEFAULT,
> @@ -123,7 +126,6 @@ static struct rte_eth_conf port_conf = {
>  		.mq_mode = ETH_MQ_RX_RSS,
>  		.max_rx_pkt_len = RTE_ETHER_MAX_LEN,
>  		.split_hdr_size = 0,
> -		.offloads = DEV_RX_OFFLOAD_CHECKSUM,
>  	},
>  	.rx_adv_conf = {
>  		.rss_conf = {
> @@ -981,6 +983,7 @@ prepare_ptype_parser(uint16_t portid, uint16_t
> queueid)
>  	return 0;
>  }
> 
> +
>  static void
>  l3fwd_poll_resource_setup(void)
>  {
> @@ -993,7 +996,8 @@ l3fwd_poll_resource_setup(void)
>  	unsigned int nb_ports;
>  	unsigned int lcore_id;
>  	int ret;
> -
> +	l3_sft_cksum = false;
> +	l4_sft_cksum = false;
>  	if (check_lcore_params() < 0)
>  		rte_exit(EXIT_FAILURE, "check_lcore_params failed\n");
> 
> @@ -1034,11 +1038,34 @@ l3fwd_poll_resource_setup(void)
>  			rte_exit(EXIT_FAILURE,
>  				"Error during getting device (port %u) info:
> %s\n",
>  				portid, strerror(-ret));
> -
>  		if (dev_info.tx_offload_capa &
> DEV_TX_OFFLOAD_MBUF_FAST_FREE)
>  			local_port_conf.txmode.offloads |=
>  				DEV_TX_OFFLOAD_MBUF_FAST_FREE;
> 
> +		if (dev_info.rx_offload_capa &
> DEV_RX_OFFLOAD_IPV4_CKSUM)
> +			local_port_conf.rxmode.offloads |=
> +			DEV_RX_OFFLOAD_IPV4_CKSUM;
> +		else {
> +			l3_sft_cksum = true;
> +			printf("WARNING: IPV4 checksum offload not
> available.\n");
> +			}
> +
> +		if (dev_info.rx_offload_capa &
> DEV_RX_OFFLOAD_UDP_CKSUM)
> +			local_port_conf.rxmode.offloads |=
> +				DEV_RX_OFFLOAD_UDP_CKSUM;
> +		else {
> +			l4_sft_cksum = true;
> +			printf("WARNING: UDP checksum offload not
> available.\n");
> +		}
> +
> +		if (dev_info.rx_offload_capa &
> DEV_RX_OFFLOAD_TCP_CKSUM)
> +			local_port_conf.rxmode.offloads |=
> +				DEV_RX_OFFLOAD_TCP_CKSUM;
> +		else {
> +			l4_sft_cksum = true;
> +			printf("WARNING: TCP checksum offload not
> available.\n");
> +		}
> +
>  		local_port_conf.rx_adv_conf.rss_conf.rss_hf &=
>  			dev_info.flow_type_rss_offloads;
> 
> --
> 2.25.1