diff options
Diffstat (limited to 'net/mptcp')
| -rw-r--r-- | net/mptcp/protocol.h | 4 | ||||
| -rw-r--r-- | net/mptcp/subflow.c | 105 |
2 files changed, 103 insertions, 6 deletions
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 76194babc754..12637299b42e 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -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, diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 9b82ce635c6e..9ccc4686d0d4 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -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 @@ validate_seq: 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, |