slirp/ncsi: add checksum support

The checksum field of a NC-SI packet contains a value that may be
included in each command and response. The verification is optional
but the Linux driver does so when a non-zero value is provided. Let's
extend the model to compute the checksum value and exercise a little
more the Linux driver.

See section "8.2.2.3 - 2's Complement Checksum Compensation" in the
Network Controller Sideband Interface (NC-SI) Specification for more
details.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
This commit is contained in:
Cédric Le Goater 2018-05-30 08:10:35 +02:00 committed by Samuel Thibault
parent b2d1678fa1
commit 47335eeea8

View file

@ -1,7 +1,7 @@
/*
* NC-SI (Network Controller Sideband Interface) "echo" model
*
* Copyright (C) 2016 IBM Corp.
* Copyright (C) 2016-2018 IBM Corp.
*
* This code is licensed under the GPL version 2 or later. See the
* COPYING file in the top-level directory.
@ -11,6 +11,23 @@
#include "ncsi-pkt.h"
static uint32_t ncsi_calculate_checksum(uint16_t *data, int len)
{
uint32_t checksum = 0;
int i;
/*
* 32-bit unsigned sum of the NC-SI packet header and NC-SI packet
* payload interpreted as a series of 16-bit unsigned integer values.
*/
for (i = 0; i < len; i++) {
checksum += htons(data[i]);
}
checksum = (~checksum + 1);
return checksum;
}
/* Get Capabilities */
static int ncsi_rsp_handler_gc(struct ncsi_rsp_pkt_hdr *rnh)
{
@ -101,6 +118,9 @@ void ncsi_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
(ncsi_reply + ETH_HLEN);
const struct ncsi_rsp_handler *handler = NULL;
int i;
int ncsi_rsp_len = sizeof(*nh);
uint32_t checksum;
uint32_t *pchecksum;
memset(ncsi_reply, 0, sizeof(ncsi_reply));
@ -130,15 +150,18 @@ void ncsi_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
/* TODO: handle errors */
handler->handler(rnh);
}
ncsi_rsp_len += handler->payload;
} else {
rnh->common.length = 0;
rnh->code = htons(NCSI_PKT_RSP_C_UNAVAILABLE);
rnh->reason = htons(NCSI_PKT_RSP_R_UNKNOWN);
}
/* TODO: add a checksum at the end of the frame but the specs
* allows it to be zero */
/* Add the optional checksum at the end of the frame. */
checksum = ncsi_calculate_checksum((uint16_t *) rnh, ncsi_rsp_len);
pchecksum = (uint32_t *)((void *) rnh + ncsi_rsp_len);
*pchecksum = htonl(checksum);
ncsi_rsp_len += 4;
slirp_output(slirp->opaque, ncsi_reply, ETH_HLEN + sizeof(*nh) +
(handler ? handler->payload : 0) + 4);
slirp_output(slirp->opaque, ncsi_reply, ETH_HLEN + ncsi_rsp_len);
}