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sys/netgraph/ng_vlan_rotate.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 IKS Service GmbH
* All rights reserved.
*
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* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Author: Lutz Donnerhacke <lutz@donnerhacke.de>
*
* $FreeBSD$
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Same.

kp: Same.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/syslog.h>
#include <net/ethernet.h>
#include <netgraph/ng_message.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_vlan_rotate.h>
#include <netgraph/netgraph.h>
/*
* This section contains the netgraph method declarations for the
* sample node. These methods define the netgraph 'type'.
*/
static ng_constructor_t ng_vlanrotate_constructor;
static ng_rcvmsg_t ng_vlanrotate_rcvmsg;
static ng_shutdown_t ng_vlanrotate_shutdown;
static ng_newhook_t ng_vlanrotate_newhook;
static ng_rcvdata_t ng_vlanrotate_rcvdata;
static ng_disconnect_t ng_vlanrotate_disconnect;
/* Parse type for struct ng_vlanrotate_conf */
static const struct ng_parse_struct_field ng_vlanrotate_conf_fields[] = {
{"rot", &ng_parse_int8_type},
{"min", &ng_parse_uint8_type},
{"max", &ng_parse_uint8_type},
{NULL}
};
static const struct ng_parse_type ng_vlanrotate_conf_type = {
&ng_parse_struct_type,
&ng_vlanrotate_conf_fields
};
/* Parse type for struct ng_vlanrotate_stat */
static struct ng_parse_fixedarray_info ng_vlanrotate_stat_hist_info = {
&ng_parse_uint64_type,
NG_VLANROTATE_MAX_VLANS
};
static struct ng_parse_type ng_vlanrotate_stat_hist = {
&ng_parse_fixedarray_type,
&ng_vlanrotate_stat_hist_info
};
static const struct ng_parse_struct_field ng_vlanrotate_stat_fields[] = {
{"drops", &ng_parse_uint64_type},
{"excessive", &ng_parse_uint64_type},
{"incomplete", &ng_parse_uint64_type},
{"histogram", &ng_vlanrotate_stat_hist},
{NULL}
};
static struct ng_parse_type ng_vlanrotate_stat_type = {
&ng_parse_struct_type,
&ng_vlanrotate_stat_fields
};
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_vlanrotate_cmdlist[] = {
{
NGM_VLANROTATE_COOKIE,
NGM_VLANROTATE_GET_CONF,
"getconf",
NULL,
&ng_vlanrotate_conf_type,
},
{
NGM_VLANROTATE_COOKIE,
NGM_VLANROTATE_SET_CONF,
"setconf",
&ng_vlanrotate_conf_type,
NULL
},
{
NGM_VLANROTATE_COOKIE,
NGM_VLANROTATE_GET_STAT,
"getstat",
NULL,
&ng_vlanrotate_stat_type
},
{
NGM_VLANROTATE_COOKIE,
NGM_VLANROTATE_CLR_STAT,
"clrstat",
NULL,
&ng_vlanrotate_stat_type
},
{
NGM_VLANROTATE_COOKIE,
NGM_VLANROTATE_GETCLR_STAT,
"getclrstat",
NULL,
&ng_vlanrotate_stat_type
},
{0}
};
/* Netgraph node type descriptor */
static struct ng_type typestruct = {
.version = NG_ABI_VERSION,
.name = NG_VLANROTATE_NODE_TYPE,
.constructor = ng_vlanrotate_constructor,
.rcvmsg = ng_vlanrotate_rcvmsg,
.shutdown = ng_vlanrotate_shutdown,
.newhook = ng_vlanrotate_newhook,
.rcvdata = ng_vlanrotate_rcvdata,
.disconnect = ng_vlanrotate_disconnect,
.cmdlist = ng_vlanrotate_cmdlist,
};
NETGRAPH_INIT(vlanrotate, &typestruct);
/* Information we store for each node */
struct vlanrotate {
hook_p original_hook;
hook_p ordered_hook;
hook_p excessive_hook;
hook_p incomplete_hook;
struct ng_vlanrotate_conf conf;
struct ng_vlanrotate_stat stat;
};
typedef struct vlanrotate *vlanrotate_p;
/*
* Set up the private data structure.
*/
static int
ng_vlanrotate_constructor(node_p node)
{
vlanrotate_p vrp = malloc(sizeof(*vrp), M_NETGRAPH, M_WAITOK | M_ZERO);
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vrp->conf.max = NG_VLANROTATE_MAX_VLANS;
NG_NODE_SET_PRIVATE(node, vrp);
return (0);
}
/*
* Give our ok for a hook to be added.
*/
static int
ng_vlanrotate_newhook(node_p node, hook_p hook, const char *name)
{
const vlanrotate_p vrp = NG_NODE_PRIVATE(node);
hook_p *dst = NULL;
if (strcmp(name, NG_VLANROTATE_HOOK_ORDERED) == 0) {
dst = &vrp->ordered_hook;
} else if (strcmp(name, NG_VLANROTATE_HOOK_ORIGINAL) == 0) {
dst = &vrp->original_hook;
} else if (strcmp(name, NG_VLANROTATE_HOOK_EXCESSIVE) == 0) {
dst = &vrp->excessive_hook;
} else if (strcmp(name, NG_VLANROTATE_HOOK_INCOMPLETE) == 0) {
dst = &vrp->incomplete_hook;
}
if (dst == NULL)
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Or maybe just 'else' in the above if/else cascade?

kp: Or maybe just 'else' in the above if/else cascade?
return (EINVAL); /* not a hook we know about */
if (*dst != NULL)
return (EADDRINUSE); /* don't override */
*dst = hook;
return (0);
}
/*
* Get a netgraph control message.
* A response is not required.
*/
static int
ng_vlanrotate_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
const vlanrotate_p vrp = NG_NODE_PRIVATE(node);
struct ng_mesg *resp = NULL;
int error = 0;
struct ng_mesg *msg;
struct ng_vlanrotate_conf *pcf;
NGI_GET_MSG(item, msg);
/* Deal with message according to cookie and command */
switch (msg->header.typecookie) {
case NGM_VLANROTATE_COOKIE:
switch (msg->header.cmd) {
case NGM_VLANROTATE_GET_CONF:
NG_MKRESPONSE(resp, msg, sizeof(vrp->conf), M_NOWAIT);
if (!resp) {
error = ENOMEM;
break;
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}
*((struct ng_vlanrotate_conf *)resp->data) = vrp->conf;
break;
case NGM_VLANROTATE_SET_CONF:
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kevans: The various case lines should line up with the switch
if (msg->header.arglen != sizeof(*pcf)) {
error = EINVAL;
break;
}
pcf = (struct ng_vlanrotate_conf *)msg->data;
if (pcf->max == 0)
pcf->max = vrp->conf.max; /* keep current value */
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kp: Line length.
if ((pcf->max > NG_VLANROTATE_MAX_VLANS) ||
(pcf->min > pcf->max) ||
(abs(pcf->rot) >= pcf->max)) {
error = EINVAL;
break;
}
vrp->conf = *pcf;
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break;
case NGM_VLANROTATE_GET_STAT:
case NGM_VLANROTATE_GETCLR_STAT:
NG_MKRESPONSE(resp, msg, sizeof(vrp->stat), M_NOWAIT);
if (!resp) {
error = ENOMEM;
break;
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}
*(struct ng_vlanrotate_stat *)resp->data = vrp->stat;
if (msg->header.cmd != NGM_VLANROTATE_GETCLR_STAT)
break;
case NGM_VLANROTATE_CLR_STAT:
bzero(&(vrp->stat), sizeof(vrp->stat));
break;
default:
error = EINVAL; /* unknown command */
break;
}
break;
default:
error = EINVAL; /* unknown cookie type */
break;
}
/* Take care of synchronous response, if any */
NG_RESPOND_MSG(error, node, item, resp);
/* Free the message and return */
NG_FREE_MSG(msg);
return (error);
}
/*
* Receive data, and do rotate the vlans as desired.
*
* Rotating is quite complicated if the rotation offset and the number
* of vlans are not relativly prime. In this case multiple slices need
* to be rotated seperatly.
*
* Rotation can be additive or subtractive. Some examples:
* 01234 5 vlans given
* -----
* 34012 +2 rotate
* 12340 +4 rotate
* 12340 -1 rotate
*
* First some helper functions ...
*/
struct ether_vlan_stack_entry {
uint16_t proto;
uint16_t tag;
} __packed;
struct ether_vlan_stack_header {
uint8_t dst[ETHER_ADDR_LEN];
uint8_t src[ETHER_ADDR_LEN];
struct ether_vlan_stack_entry vlan_stack[1];
} __packed;
static int
ng_vlanrotate_gcd(int a, int b)
{
if (b == 0)
return a;
else
return ng_vlanrotate_gcd(b, a % b);
}
static void
ng_vlanrotate_rotate(struct ether_vlan_stack_entry arr[], int d, int n)
{
int i, j, k;
struct ether_vlan_stack_entry temp;
/* for each commensurable slice */
for (i = ng_vlanrotate_gcd(d, n); i-- > 0;) {
/* rotate left aka downwards */
temp = arr[i];
j = i;
while (1) {
k = j + d;
if (k >= n)
k = k - n;
if (k == i)
break;
arr[j] = arr[k];
j = k;
}
arr[j] = temp;
}
}
static int
ng_vlanrotate_rcvdata(hook_p hook, item_p item)
{
const vlanrotate_p vrp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
struct mbuf *m = NULL;
hook_p dst_hook;
int8_t rotate;
int8_t vlans = 0;
int error = ENOSYS;
struct ether_vlan_stack_header *evsh;
NGI_GET_M(item, m);
if (hook == vrp->ordered_hook) {
rotate = +vrp->conf.rot;
dst_hook = vrp->original_hook;
} else if (hook == vrp->original_hook) {
rotate = -vrp->conf.rot;
dst_hook = vrp->ordered_hook;
} else {
dst_hook = vrp->original_hook;
goto send; /* everything else goes out unmodified */
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We don't traditionally space assignments out like this, but I don't know that anyone's going to hassle over it.

kevans: We don't traditionally space assignments out like this, but I don't know that anyone's going to…
}
if (dst_hook == NULL) {
error = ENETDOWN;
goto fail;
}
/* count the vlans */
for (vlans = 0; vlans <= NG_VLANROTATE_MAX_VLANS; vlans++) {
size_t expected_len = sizeof(struct ether_vlan_stack_header) + vlans * sizeof(struct ether_vlan_stack_entry);
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if (m->m_len < expected_len) {
m = m_pullup(m, expected_len);
if (m == NULL) {
error = EINVAL;
goto fail;
}
}
evsh = mtod(m, struct ether_vlan_stack_header *);
switch (ntohs(evsh->vlan_stack[vlans].proto)) {
case ETHERTYPE_VLAN:
case ETHERTYPE_QINQ:
case ETHERTYPE_8021Q9100:
case ETHERTYPE_8021Q9200:
case ETHERTYPE_8021Q9300:
break;
default:
goto out;
}
}
out:
if ((vlans > vrp->conf.max) || (vlans >= NG_VLANROTATE_MAX_VLANS)) {
vrp->stat.excessive++;
dst_hook = vrp->excessive_hook;
goto send;
}
if ((vlans < vrp->conf.min) || (vlans <= abs(rotate))) {
vrp->stat.incomplete++;
dst_hook = vrp->incomplete_hook;
goto send;
}
vrp->stat.histogram[vlans]++;
/* rotating upwards always (using modular arithmetics) */
if (rotate == 0) {
/* nothing to do */
} else if (rotate > 0) {
ng_vlanrotate_rotate(evsh->vlan_stack, rotate, vlans);
} else {
ng_vlanrotate_rotate(evsh->vlan_stack, vlans + rotate, vlans);
}
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send:
if (dst_hook == NULL)
goto fail;
NG_FWD_NEW_DATA(error, item, dst_hook, m);
return 0;
fail:
vrp->stat.drops++;
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Are netgraph nodes implicitly locked?
If not, this could potentially miscount if two cores run the function at the same time. Not a huge issue, but perhaps counter(9) would be useful here.

kp: Are netgraph nodes implicitly locked? If not, this could potentially miscount if two cores run…
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They are not locked automatically (which is good).
So you are right, I've to switch to the counter framework.

donner: They are not locked automatically (which is good). So you are right, I've to switch to the…
if (m != NULL)
m_freem(m);
NG_FREE_ITEM(item);
return (error);
}
/*
* Do local shutdown processing..
* All our links and the name have already been removed.
*/
static int
ng_vlanrotate_shutdown(node_p node)
{
const vlanrotate_p vrp = NG_NODE_PRIVATE(node);
NG_NODE_SET_PRIVATE(node, NULL);
NG_NODE_UNREF(node);
free(vrp, M_NETGRAPH);
return (0);
}
/*
* Hook disconnection
* For this type, removal of the last link destroys the node
*/
static int
ng_vlanrotate_disconnect(hook_p hook)
{
const vlanrotate_p vrp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
if (vrp->original_hook == hook)
vrp->original_hook = NULL;
if (vrp->ordered_hook == hook)
vrp->ordered_hook = NULL;
if (vrp->excessive_hook == hook)
vrp->excessive_hook = NULL;
if (vrp->incomplete_hook == hook)
vrp->incomplete_hook = NULL;
/* during shutdown the node is invalid, don't shutdown twice */
if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) &&
(NG_NODE_IS_VALID(NG_HOOK_NODE(hook))))
ng_rmnode_self(NG_HOOK_NODE(hook));
return (0);
}
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Operator belongs to the line before it, with the wrapping starting just after.

kevans: Operator belongs to the line before it, with the wrapping starting just after.