[PATCH v2] net: macsec SCI assignment for ES = 0

From: carlos . fernandez
Date: Fri Jun 16 2023 - 05:24:26 EST


From: Carlos Fernandez <carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxxx>

According to 802.1AE standard, when ES and SC flags in TCI are zero, used
SCI should be the current active SC_RX. Current kernel does not implement
it and uses the header MAC address.

Without this patch, when ES = 0 (using a bridge or switch), header MAC
will not fit the SCI and MACSec frames will be discarted.

Signed-off-by: Carlos Fernandez <carlos.fernandez@xxxxxxxxxxxxxxxxxxxxxxx>
---
drivers/net/macsec.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 3427993f94f7..ccecb7eb385c 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -256,16 +256,31 @@ static sci_t make_sci(const u8 *addr, __be16 port)
return sci;
}

-static sci_t macsec_frame_sci(struct macsec_eth_header *hdr, bool sci_present)
+static sci_t macsec_frame_sci(struct macsec_eth_header *hdr, bool sci_present,
+ struct macsec_rxh_data *rxd)
{
+ struct macsec_dev *macsec_device;
sci_t sci;

- if (sci_present)
+ if (sci_present) {
memcpy(&sci, hdr->secure_channel_id,
- sizeof(hdr->secure_channel_id));
- else
+ sizeof(hdr->secure_channel_id));
+ } else if (0 == (hdr->tci_an & (MACSEC_TCI_ES | MACSEC_TCI_SC))) {
+ list_for_each_entry_rcu(macsec_device, &rxd->secys, secys) {
+ struct macsec_rx_sc *rx_sc;
+ struct macsec_secy *secy = &macsec_device->secy;
+
+ for_each_rxsc(secy, rx_sc) {
+ rx_sc = rx_sc ? macsec_rxsc_get(rx_sc) : NULL;
+ if (rx_sc && rx_sc->active)
+ return rx_sc->sci;
+ }
+ /* If not found, use MAC in hdr as default*/
+ sci = make_sci(hdr->eth.h_source, MACSEC_PORT_ES);
+ }
+ } else {
sci = make_sci(hdr->eth.h_source, MACSEC_PORT_ES);
-
+ }
return sci;
}

@@ -1150,11 +1165,12 @@ static rx_handler_result_t macsec_handle_frame(struct sk_buff **pskb)

macsec_skb_cb(skb)->has_sci = !!(hdr->tci_an & MACSEC_TCI_SC);
macsec_skb_cb(skb)->assoc_num = hdr->tci_an & MACSEC_AN_MASK;
- sci = macsec_frame_sci(hdr, macsec_skb_cb(skb)->has_sci);

rcu_read_lock();
rxd = macsec_data_rcu(skb->dev);

+ sci = macsec_frame_sci(hdr, macsec_skb_cb(skb)->has_sci, rxd);
+
list_for_each_entry_rcu(macsec, &rxd->secys, secys) {
struct macsec_rx_sc *sc = find_rx_sc(&macsec->secy, sci);

--
2.34.1