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Date: Sat, 29 May 2021 14:05:55 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Justin Iurman <justin.iurman@...ege.be>
Cc: netdev@...r.kernel.org, davem@...emloft.net, tom@...bertland.com
Subject: Re: [PATCH net-next v4 2/5] ipv6: ioam: Data plane support for
Pre-allocated Trace
On Thu, 27 May 2021 17:16:49 +0200 Justin Iurman wrote:
> Implement support for processing the IOAM Pre-allocated Trace with IPv6,
> see [1] and [2]. Introduce a new IPv6 Hop-by-Hop TLV option, see IANA [3].
>
> A per-interface sysctl ioam6_enabled is provided to process/ignore IOAM
> headers. Default is ignore (= disabled). Another per-interface sysctl
> ioam6_id is provided to define the IOAM (unique) identifier of the
> interface. Default is 0. A per-namespace sysctl ioam6_id is provided to
> define the IOAM (unique) identifier of the node. Default is 0.
Last two sentences are repeated.
Is 0 a valid interface ID? If not why not use id != 0 instead of
having a separate enabled field?
> Documentation is provided at the end of this patchset.
>
> Two relativistic hash tables: one for IOAM namespaces, the other for
> IOAM schemas. A namespace can only have a single active schema and a
> schema can only be attached to a single namespace (1:1 relationship).
>
> [1] https://tools.ietf.org/html/draft-ietf-ippm-ioam-ipv6-options
> [2] https://tools.ietf.org/html/draft-ietf-ippm-ioam-data
> [3] https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml#ipv6-parameters-2
>
> Signed-off-by: Justin Iurman <justin.iurman@...ege.be>
> +extern struct ioam6_namespace *ioam6_namespace(struct net *net, __be16 id);
> +extern void ioam6_fill_trace_data(struct sk_buff *skb,
> + struct ioam6_namespace *ns,
> + struct ioam6_trace_hdr *trace);
> +
> +extern int ioam6_init(void);
> +extern void ioam6_exit(void);
no need for externs in new headers
> +#endif /* _NET_IOAM6_H */
> diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
> index bde0b7adb4a3..a0d61a8fcfe1 100644
> --- a/include/net/netns/ipv6.h
> +++ b/include/net/netns/ipv6.h
> @@ -53,6 +53,7 @@ struct netns_sysctl_ipv6 {
> int seg6_flowlabel;
> bool skip_notify_on_dev_down;
> u8 fib_notify_on_flag_change;
> + unsigned int ioam6_id;
Perhaps move it after seg6_flowlabel, better chance next person adding
a 1 byte type will not create a hole.
> };
>
> struct netns_ipv6 {
> @@ -6932,6 +6938,20 @@ static const struct ctl_table addrconf_sysctl[] = {
> .mode = 0644,
> .proc_handler = proc_dointvec,
> },
> + {
> + .procname = "ioam6_enabled",
> + .data = &ipv6_devconf.ioam6_enabled,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
This one should be constrained to 0/1, right?
proc_dou8vec_minmax? no need for full u32.
> + },
> + {
> + .procname = "ioam6_id",
> + .data = &ipv6_devconf.ioam6_id,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
uint?
> + },
> {
> /* sentinel */
> }
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index 2389ff702f51..aec9664ec909 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -62,6 +62,7 @@
> #include <net/rpl.h>
> #include <net/compat.h>
> #include <net/xfrm.h>
> +#include <net/ioam6.h>
>
> #include <linux/uaccess.h>
> #include <linux/mroute6.h>
> @@ -1191,6 +1192,10 @@ static int __init inet6_init(void)
> if (err)
> goto rpl_fail;
>
> + err = ioam6_init();
> + if (err)
> + goto ioam6_fail;
> +
> err = igmp6_late_init();
> if (err)
> goto igmp6_late_err;
> @@ -1214,6 +1219,8 @@ static int __init inet6_init(void)
> #endif
> igmp6_late_err:
> rpl_exit();
> +ioam6_fail:
> + ioam6_exit();
> rpl_fail:
This is out of order, ioam6_fail should now jump to rpl_exit()
and igmp6_late_err should point at ioam6_exit().
> seg6_exit();
> seg6_fail:
> @@ -929,6 +932,50 @@ static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
> return false;
> }
>
> +/* IOAM */
> +
> +static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
> +{
> + struct ioam6_trace_hdr *trace;
> + struct ioam6_namespace *ns;
> + struct ioam6_hdr *hdr;
> +
> + /* Must be 4n-aligned */
> + if (optoff & 3)
> + goto drop;
> +
> + /* Ignore if IOAM is not enabled on ingress */
> + if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
> + goto ignore;
> +
> + hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
> +
> + switch (hdr->type) {
> + case IOAM6_TYPE_PREALLOC:
> + trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
> + ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
Shouldn't there be validation that the header is not truncated or
malformed before we start poking into the fields?
> + /* Ignore if the IOAM namespace is unknown */
> + if (!ns)
> + goto ignore;
> +
> + if (!skb_valid_dst(skb))
> + ip6_route_input(skb);
> +
> + ioam6_fill_trace_data(skb, ns, trace);
> + break;
> + default:
> + break;
> + }
> +
> +ignore:
> + return true;
> +
> +drop:
> + kfree_skb(skb);
> + return false;
> +}
> +
> +void ioam6_fill_trace_data(struct sk_buff *skb,
> + struct ioam6_namespace *ns,
> + struct ioam6_trace_hdr *trace)
> +{
> + u8 sclen = 0;
> +
> + /* Skip if Overflow flag is set OR
> + * if an unknown type (bit 12-21) is set
> + */
> + if (trace->overflow ||
> + (trace->type.bit12 | trace->type.bit13 | trace->type.bit14 |
> + trace->type.bit15 | trace->type.bit16 | trace->type.bit17 |
> + trace->type.bit18 | trace->type.bit19 | trace->type.bit20 |
> + trace->type.bit21)) {
> + return;
> + }
braces unnecessary
> +
> + /* NodeLen does not include Opaque State Snapshot length. We need to
> + * take it into account if the corresponding bit is set (bit 22) and
> + * if the current IOAM namespace has an active schema attached to it
> + */
> + if (trace->type.bit22) {
> + sclen = sizeof_field(struct ioam6_schema, hdr) / 4;
> +
> + if (ns->schema)
> + sclen += ns->schema->len / 4;
> + }
> +
> + /* If there is no space remaining, we set the Overflow flag and we
> + * skip without filling the trace
> + */
> + if (!trace->remlen || trace->remlen < (trace->nodelen + sclen)) {
brackets around sum unnecessary
> + trace->overflow = 1;
> + return;
> + }
> +
> + __ioam6_fill_trace_data(skb, ns, trace, sclen);
> + trace->remlen -= trace->nodelen + sclen;
> +}
> diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
> index d7cf26f730d7..b97aad7b6aca 100644
> --- a/net/ipv6/sysctl_net_ipv6.c
> +++ b/net/ipv6/sysctl_net_ipv6.c
> @@ -196,6 +196,13 @@ static struct ctl_table ipv6_table_template[] = {
> .extra1 = SYSCTL_ZERO,
> .extra2 = &two,
> },
> + {
> + .procname = "ioam6_id",
> + .data = &init_net.ipv6.sysctl.ioam6_id,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = proc_dointvec
uint?
> + },
> { }
> };
>
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