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authorCédric Le Goater <clg@kaod.org>2018-05-30 08:10:35 +0200
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2018-05-31 21:19:24 +0200
commit47335eeea8f1d14b7c6a1dd585a25a9166721168 (patch)
treea189731f5476000fae263196ca83308e1a076f0b /slirp
parentb2d1678fa1733144826f582d28020da39372649f (diff)
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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>
Diffstat (limited to 'slirp')
-rw-r--r--slirp/ncsi.c33
1 files changed, 28 insertions, 5 deletions
diff --git a/slirp/ncsi.c b/slirp/ncsi.c
index 7b3fff2..7116034 100644
--- a/slirp/ncsi.c
+++ b/slirp/ncsi.c
@@ -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);
}