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From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Yicai Lu <luyicai@huawei.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "zhoujingbin@huawei.com" <zhoujingbin@huawei.com>,
	"chenchanghu@huawei.com" <chenchanghu@huawei.com>,
	"jerry.lilijun@huawei.com" <jerry.lilijun@huawei.com>,
	"haifeng.lin@huawei.com" <haifeng.lin@huawei.com>,
	"guohongzhi1@huawei.com" <guohongzhi1@huawei.com>,
	"wangyunjian@huawei.com" <wangyunjian@huawei.com>,
	"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v6] ip_frag: remove padding length of fragment
Date: Fri, 18 Dec 2020 11:41:33 +0000	[thread overview]
Message-ID: <BYAPR11MB3301E8D991652111ACCD32CE9AC30@BYAPR11MB3301.namprd11.prod.outlook.com> (raw)
In-Reply-To: <1608125790-26496-1-git-send-email-luyicai@huawei.com>



> 
> In some situations, we would get several ip fragments, which total
> data length is less than min_ip_len(64) and padding with zeros.
> We simulated intermediate fragments by modifying the MTU.
> To illustrate the problem, we simplify the packet format and
> ignore the impact of the packet header.In namespace2,
> a packet whose data length is 1520 is sent.
> When the packet passes tap2, the packet is divided into two
> fragments: fragment A and B, similar to (1520 = 1510 + 10).
> When the packet passes tap3, the larger fragment packet A is
> divided into two fragments A1 and A2, similar to (1510 = 1500 + 10).
> Finally, the bond interface receives three fragments:
> A1, A2, and B (1520 = 1500 + 10 + 10).
> One fragmented packet A2 is smaller than the minimum Ethernet
> frame length, so it needs to be padded.
> 
> |---------------------------------------------------|
> |                      HOST                         |
> | |--------------|   |----------------------------| |
> | |      ns2     |   |      |--------------|      | |
> | |  |--------|  |   |  |--------|    |--------|  | |
> | |  |  tap1  |  |   |  |  tap2  | ns1|  tap3  |  | |
> | |  |mtu=1510|  |   |  |mtu=1510|    |mtu=1500|  | |
> | |--|1.1.1.1 |--|   |--|1.1.1.2 |----|2.1.1.1 |--| |
> |    |--------|         |--------|    |--------|    |
> |         |                 |              |        |
> |         |-----------------|              |        |
> |                                          |        |
> |                                      |--------|   |
> |                                      |  bond  |   |
> |--------------------------------------|mtu=1500|---|
>                                        |--------|
> 
> When processing the preceding packets above,
> DPDK would aggregate fragmented packets A2 and B.
> And error packets are generated, which padding(zero)
> is displayed in the middle of the packet.
> 
> A2 + B:
> 0000   fa 16 3e 9f fb 82 fa 47 b2 57 dc 20 08 00 45 00
> 0010   00 33 b4 66 00 ba 3f 01 c1 a5 01 01 01 01 02 01
> 0020   01 02 c0 c1 c2 c3 c4 c5 c6 c7 00 00 00 00 00 00
> 0030   00 00 00 00 00 00 00 00 00 00 00 00 c8 c9 ca cb
> 0040   cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db
> 0050   dc dd de df e0 e1 e2 e3 e4 e5 e6
> 
> So, we would calculate the length of padding, and remove
> the padding in pkt_len and data_len before aggregation.
> And also we have the fix for both ipv4 and ipv6.
> 
> Fixes: 7f0983ee331c ("ip_frag: check fragment length of incoming packet")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yicai Lu <luyicai@huawei.com>
> ---
> v5 -> v6: Have the fix for ipv6.
> ---
>  lib/librte_ip_frag/rte_ipv4_reassembly.c | 11 ++++++++---
>  lib/librte_ip_frag/rte_ipv6_reassembly.c |  9 +++++++--
>  2 files changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_ip_frag/rte_ipv4_reassembly.c b/lib/librte_ip_frag/rte_ipv4_reassembly.c
> index 1dda8ac..69666c8 100644
> --- a/lib/librte_ip_frag/rte_ipv4_reassembly.c
> +++ b/lib/librte_ip_frag/rte_ipv4_reassembly.c
> @@ -104,6 +104,7 @@ struct rte_mbuf *
>  	const unaligned_uint64_t *psd;
>  	uint16_t flag_offset, ip_ofs, ip_flag;
>  	int32_t ip_len;
> +	int32_t trim;
> 
>  	flag_offset = rte_be_to_cpu_16(ip_hdr->fragment_offset);
>  	ip_ofs = (uint16_t)(flag_offset & RTE_IPV4_HDR_OFFSET_MASK);
> @@ -117,14 +118,15 @@ struct rte_mbuf *
> 
>  	ip_ofs *= RTE_IPV4_HDR_OFFSET_UNITS;
>  	ip_len = rte_be_to_cpu_16(ip_hdr->total_length) - mb->l3_len;
> +	trim = mb->pkt_len - (ip_len + mb->l3_len + mb->l2_len);
> 
>  	IP_FRAG_LOG(DEBUG, "%s:%d:\n"
> -		"mbuf: %p, tms: %" PRIu64
> -		", key: <%" PRIx64 ", %#x>, ofs: %u, len: %d, flags: %#x\n"
> +		"mbuf: %p, tms: %" PRIu64 ", key: <%" PRIx64 ", %#x>"
> +		"ofs: %u, len: %d, padding: %d, flags: %#x\n"
>  		"tbl: %p, max_cycles: %" PRIu64 ", entry_mask: %#x, "
>  		"max_entries: %u, use_entries: %u\n\n",
>  		__func__, __LINE__,
> -		mb, tms, key.src_dst[0], key.id, ip_ofs, ip_len, ip_flag,
> +		mb, tms, key.src_dst[0], key.id, ip_ofs, ip_len, trim, ip_flag,
>  		tbl, tbl->max_cycles, tbl->entry_mask, tbl->max_entries,
>  		tbl->use_entries);
> 
> @@ -134,6 +136,9 @@ struct rte_mbuf *
>  		return NULL;
>  	}
> 
> +	if (unlikely(trim > 0))
> +		rte_pktmbuf_trim(mb, trim);
> +
>  	/* try to find/add entry into the fragment's table. */
>  	if ((fp = ip_frag_find(tbl, dr, &key, tms)) == NULL) {
>  		IP_FRAG_MBUF2DR(dr, mb);
> diff --git a/lib/librte_ip_frag/rte_ipv6_reassembly.c b/lib/librte_ip_frag/rte_ipv6_reassembly.c
> index ad01055..4037da0 100644
> --- a/lib/librte_ip_frag/rte_ipv6_reassembly.c
> +++ b/lib/librte_ip_frag/rte_ipv6_reassembly.c
> @@ -142,6 +142,7 @@ struct rte_mbuf *
>  	struct ip_frag_key key;
>  	uint16_t ip_ofs;
>  	int32_t ip_len;
> +	int32_t trim;
> 
>  	rte_memcpy(&key.src_dst[0], ip_hdr->src_addr, 16);
>  	rte_memcpy(&key.src_dst[2], ip_hdr->dst_addr, 16);
> @@ -158,16 +159,17 @@ struct rte_mbuf *
>  	 * this is what we remove from the payload len.
>  	 */
>  	ip_len = rte_be_to_cpu_16(ip_hdr->payload_len) - sizeof(*frag_hdr);
> +	trim = mb->pkt_len - (ip_len + mb->l3_len + mb->l2_len);
> 
>  	IP_FRAG_LOG(DEBUG, "%s:%d:\n"
>  		"mbuf: %p, tms: %" PRIu64
>  		", key: <" IPv6_KEY_BYTES_FMT ", %#x>, "
> -		"ofs: %u, len: %d, flags: %#x\n"
> +		"ofs: %u, len: %d, padding: %d, flags: %#x\n"
>  		"tbl: %p, max_cycles: %" PRIu64 ", entry_mask: %#x, "
>  		"max_entries: %u, use_entries: %u\n\n",
>  		__func__, __LINE__,
>  		mb, tms, IPv6_KEY_BYTES(key.src_dst), key.id, ip_ofs, ip_len,
> -		RTE_IPV6_GET_MF(frag_hdr->frag_data),
> +		trim, RTE_IPV6_GET_MF(frag_hdr->frag_data),
>  		tbl, tbl->max_cycles, tbl->entry_mask, tbl->max_entries,
>  		tbl->use_entries);
> 
> @@ -177,6 +179,9 @@ struct rte_mbuf *
>  		return NULL;
>  	}
> 
> +	if (unlikely(trim > 0))
> +		rte_pktmbuf_trim(mb, trim);
> +
>  	/* try to find/add entry into the fragment's table. */
>  	fp = ip_frag_find(tbl, dr, &key, tms);
>  	if (fp == NULL) {
> --

Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

> 1.9.5.msysgit.1


  reply	other threads:[~2020-12-18 11:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-18 13:29 [dpdk-dev] [PATCH] ip_frag: recalculate data " Yicai Lu
2020-11-22 11:22 ` Thomas Monjalon
2020-11-23  2:27 ` [dpdk-dev] [PATCH v2] " Yicai Lu
2020-12-12 11:05 ` [dpdk-dev] [PATCH v5] ip_frag: remove padding " Yicai Lu
2020-12-14 14:44   ` Ananyev, Konstantin
2020-12-15  3:18     ` luyicai
2020-12-16 10:44       ` Ananyev, Konstantin
2020-12-16 10:54         ` luyicai
2020-12-16 13:36 ` [dpdk-dev] [PATCH v6] " Yicai Lu
2020-12-18 11:41   ` Ananyev, Konstantin [this message]
2021-01-15 10:29     ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon

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