@@ -400,6 +400,8 @@ struct mptcp_subflow_context {
u32 map_subflow_seq;
u32 ssn_offset;
u32 map_data_len;
+ __wsum map_data_csum;
+ u32 map_csum_len;
u32 request_mptcp : 1, /* send MP_CAPABLE */
request_join : 1, /* send MP_JOIN */
request_bkup : 1,
@@ -409,6 +411,8 @@ struct mptcp_subflow_context {
pm_notified : 1, /* PM hook called for established status */
conn_finished : 1,
map_valid : 1,
+ map_csum_reqd : 1,
+ map_data_fin : 1,
mpc_map : 1,
backup : 1,
send_mp_prio : 1,
@@ -827,10 +827,90 @@ static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
return true;
}
+static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *skb,
+ bool csum_reqd)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ struct csum_pseudo_header header;
+ u32 offset, seq, delta;
+ __wsum csum;
+ int len;
+
+ if (!csum_reqd)
+ return MAPPING_OK;
+
+ /* mapping already validated on previous traversal */
+ if (subflow->map_csum_len == subflow->map_data_len)
+ return MAPPING_OK;
+
+ /* traverse the receive queue, ensuring it contains a full
+ * DSS mapping and accumulating the related csum.
+ * Preserve the accoumlate csum across multiple calls, to compute
+ * the csum only once
+ */
+ delta = subflow->map_data_len - subflow->map_csum_len;
+ for (;;) {
+ seq = tcp_sk(ssk)->copied_seq + subflow->map_csum_len;
+ offset = seq - TCP_SKB_CB(skb)->seq;
+
+ /* if the current skb has not been accounted yet, csum its contents
+ * up to the amount covered by the current DSS
+ */
+ if (offset < skb->len) {
+ __wsum csum;
+
+ len = min(skb->len - offset, delta);
+ csum = skb_checksum(skb, offset, len, 0);
+ subflow->map_data_csum = csum_block_add(subflow->map_data_csum, csum,
+ subflow->map_csum_len);
+
+ delta -= len;
+ subflow->map_csum_len += len;
+ }
+ if (delta == 0)
+ break;
+
+ if (skb_queue_is_last(&ssk->sk_receive_queue, skb)) {
+ /* if this subflow is closed, the partial mapping
+ * will be never completed; flush the pending skbs, so
+ * that subflow_sched_work_if_closed() can kick in
+ */
+ if (unlikely(ssk->sk_state == TCP_CLOSE))
+ while ((skb = skb_peek(&ssk->sk_receive_queue)))
+ sk_eat_skb(ssk, skb);
+
+ /* not enough data to validate the csum */
+ return MAPPING_EMPTY;
+ }
+
+ /* the DSS mapping for next skbs will be validated later,
+ * when a get_mapping_status call will process such skb
+ */
+ skb = skb->next;
+ }
+
+ /* note that 'map_data_len' accounts only for the carried data, does
+ * not include the eventual seq increment due to the data fin,
+ * while the pseudo header requires the original DSS data len,
+ * including that
+ */
+ header.data_seq = cpu_to_be64(subflow->map_seq);
+ header.subflow_seq = htonl(subflow->map_subflow_seq);
+ header.data_len = htons(subflow->map_data_len + subflow->map_data_fin);
+ header.csum = 0;
+
+ csum = csum_partial(&header, sizeof(header), subflow->map_data_csum);
+ if (unlikely(csum_fold(csum)))
+ return subflow->mp_join ? MAPPING_INVALID : MAPPING_DUMMY;
+
+ return MAPPING_OK;
+}
+
static enum mapping_status get_mapping_status(struct sock *ssk,
struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+ bool csum_reqd = READ_ONCE(msk->csum_enabled);
struct mptcp_ext *mpext;
struct sk_buff *skb;
u16 data_len;
@@ -923,9 +1003,10 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
/* Allow replacing only with an identical map */
if (subflow->map_seq == map_seq &&
subflow->map_subflow_seq == mpext->subflow_seq &&
- subflow->map_data_len == data_len) {
+ subflow->map_data_len == data_len &&
+ subflow->map_csum_reqd == mpext->csum_reqd) {
skb_ext_del(skb, SKB_EXT_MPTCP);
- return MAPPING_OK;
+ goto validate_csum;
}
/* If this skb data are fully covered by the current mapping,
@@ -937,17 +1018,27 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
}
/* will validate the next map after consuming the current one */
- return MAPPING_OK;
+ goto validate_csum;
}
subflow->map_seq = map_seq;
subflow->map_subflow_seq = mpext->subflow_seq;
subflow->map_data_len = data_len;
subflow->map_valid = 1;
+ subflow->map_data_fin = mpext->data_fin;
subflow->mpc_map = mpext->mpc_map;
- pr_debug("new map seq=%llu subflow_seq=%u data_len=%u",
+ subflow->map_csum_reqd = mpext->csum_reqd;
+ subflow->map_csum_len = 0;
+ subflow->map_data_csum = csum_unfold(mpext->csum);
+
+ /* Cfr RFC 8684 Section 3.3.0 */
+ if (unlikely(subflow->map_csum_reqd != csum_reqd))
+ return MAPPING_INVALID;
+
+ pr_debug("new map seq=%llu subflow_seq=%u data_len=%u csum=%d:%u",
subflow->map_seq, subflow->map_subflow_seq,
- subflow->map_data_len);
+ subflow->map_data_len, subflow->map_csum_reqd,
+ subflow->map_data_csum);
validate_seq:
/* we revalidate valid mapping on new skb, because we must ensure
@@ -957,7 +1048,9 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
return MAPPING_INVALID;
skb_ext_del(skb, SKB_EXT_MPTCP);
- return MAPPING_OK;
+
+validate_csum:
+ return validate_data_csum(ssk, skb, csum_reqd);
}
static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,