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 <c...@kaod.org>
---
slirp/ncsi.c | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/slirp/ncsi.c b/slirp/ncsi.c
index d12ba3e494b0..81c6bc5576d3 100644
--- a/slirp/ncsi.c
+++ b/slirp/ncsi.c
@@ -8,9 +8,23 @@
*/
#include "qemu/osdep.h"
#include "slirp.h"
+#include "net/checksum.h"
#include "ncsi-pkt.h"
+static uint32_t ncsi_calculate_checksum(unsigned char *data, int len)
+{
+ uint32_t checksum = 0;
+ int i;
+
+ for (i = 0; i < len; i += 2) {
+ checksum += (((uint32_t)data[i] << 8) | data[i + 1]);
+ }
+
+ checksum = (~checksum + 1);
+ return checksum;
+}
+
/* Get Capabilities */
static int ncsi_rsp_handler_gc(struct ncsi_rsp_pkt_hdr *rnh)
{
@@ -87,6 +101,9 @@ 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));
@@ -116,15 +133,19 @@ 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 a checksum at the end of the frame (the specs allows it to
+ * be zero */
+ checksum = ncsi_calculate_checksum((unsigned char *) 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);
}
--
2.7.4
