>
> According to RFC791,the options may appear or not in datagrams.
> They must be implemented by all IP modules (host and gateways).
> What is optional is their transmission in any particular datagram,
> not their implementation.So we have to deal with it during the
> fragmenting process.Add some test data for the IPv4 header optional
> field fragmenting.
>
> Signed-off-by: Huichao Cai <chcch...@163.com>
> ---
....
> diff --git a/lib/ip_frag/rte_ipv4_fragmentation.c
> b/lib/ip_frag/rte_ipv4_fragmentation.c
> index 2e7739d..bcafa29 100644
> --- a/lib/ip_frag/rte_ipv4_fragmentation.c
> +++ b/lib/ip_frag/rte_ipv4_fragmentation.c
> @@ -1,4 +1,4 @@
> -/* SPDX-License-Identifier: BSD-3-Clause
> +/* SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0)
> * Copyright(c) 2010-2014 Intel Corporation
> */
>
> @@ -12,6 +12,13 @@
>
> #include "ip_frag_common.h"
>
> +/* IP options */
> +#define RTE_IPOPT_COPY 0x80
> +#define RTE_IPOPT_CONTROL 0x00
> +#define RTE_IPOPT_END (0 | RTE_IPOPT_CONTROL)
> +#define RTE_IPOPT_NOOP (1 | RTE_IPOPT_CONTROL)
> +#define RTE_IPOPT_COPIED(o) ((o) & RTE_IPOPT_COPY)
> +
> /* Fragment Offset */
> #define RTE_IPV4_HDR_DF_SHIFT 14
> #define RTE_IPV4_HDR_MF_SHIFT 13
> @@ -41,6 +48,38 @@ static inline void __free_fragments(struct rte_mbuf *mb[],
> uint32_t num)
> rte_pktmbuf_free(mb[i]);
> }
>
> +/*
> + * Options "fragmenting", just fill options not
> + * allowed in fragments with NOOPs.
> + * Simple and stupid 8), but the most efficient way.
> + */
> +static inline void ip_options_fragment(struct rte_ipv4_hdr *iph)
> +{
> + unsigned char *optptr = (unsigned char *)iph +
> + sizeof(struct rte_ipv4_hdr);
As a nit, why not 'uint8_t *', to keep style the same through all file?
> + int l = (iph->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
> + RTE_IPV4_IHL_MULTIPLIER - sizeof(struct rte_ipv4_hdr);
We already done such calculation in rte_ipv4_fragment_packet(),
so can re-use header_len value here.
> + int optlen;
> +
> + while (l > 0) {
> + switch (*optptr) {
> + case RTE_IPOPT_END:
> + return;
> + case RTE_IPOPT_NOOP:
> + l--;
> + optptr++;
> + continue;
> + }
> + optlen = optptr[1];
> + if (optlen < 2 || optlen > l)
Why optlen==1 is not considered as valid one?
> + return;
> + if (!RTE_IPOPT_COPIED(*optptr))
> + memset(optptr, RTE_IPOPT_NOOP, optlen);
> + l -= optlen;
> + optptr += optlen;
> + }
> +}
> +
> /**
> * IPv4 fragmentation.
> *
> @@ -188,6 +227,17 @@ static inline void __free_fragments(struct rte_mbuf
> *mb[], uint32_t num)
> (uint16_t)out_pkt->pkt_len,
> flag_offset, fragment_offset, more_in_segs);
>
> + /*
> + * ANK:
What means 'ANK' here?
> dirty, but effective trick. Upgrade options only if
> + * the segment to be fragmented was THE FIRST (otherwise,
> + * options are already fixed) and make it ONCE
> + * on the initial mbuf, so that all the following fragments
> + * will inherit fixed options.
> + */
> + if ((fragment_offset == 0) &&
> + ((flag_offset & RTE_IPV4_HDR_OFFSET_MASK) == 0))
> + ip_options_fragment(in_hdr);
> +
I see two problems with that approach:
- you modify incoming packet's header - which is the change in behaviour,
and doesn't look right at all.
- you remove not-copied options from all fragments.
As I can read RFC 791 - first fragment should have a copy of all options
present
in original packet, while other fragments need to have only those that have
to be
copied.
> fragment_offset = (uint16_t)(fragment_offset +
> out_pkt->pkt_len - header_len);
>
> --
> 1.8.3.1
