This patch replaces an almost identical reduplication of code; large parts of
dccp_parse_options() are repeated as ccid2_ackvector() in ccid2.c.
Two problems are involved, apart from the duplication:
1. no separation of concerns: CCIDs should not need to be concerned with the
details of parsing header options;
2. one can not assume that Ack Vectors appear as a contiguous area within an
skb, it is legal to insert other options and/or padding in between. The
current code would throw an error and stop reading in such a case. Not good.
Details:
--------
* received Ack Vectors are parsed by dccp_parse_options() alone, which passes
the result on to the CCID-specific ccid_hc_tx_parse_options();
* CCIDs interested in using/decoding Ack Vector information need to add code
to receive parsed Ack Vectors via this interface;
* a data structure, `struct dccp_ackvec_parsed' is provided, which arranges all
Ack Vectors of a single skb into a list of parsed chunks;
* a doubly-linked list was used since insertion needs to be at the tail end;
* the associated list handling and list de-allocation routines.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
net/dccp/ackvec.c | 28 ++++++++++++++++++++++++++++
net/dccp/ackvec.h | 19 +++++++++++++++++++
net/dccp/options.c | 17 ++++++++++-------
3 files changed, 57 insertions(+), 7 deletions(-)
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
@@ -112,4 +112,23 @@ static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
{
return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
}
+
+/**
+ * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb
+ * @vec: start of vector (offset into skb)
+ * @len: length of @vec
+ * @nonce: whether @vec had an ECN nonce of 0 or 1
+ * @node: FIFO - arranged in descending order of ack_ackno
+ * This structure is used by CCIDs to access Ack Vectors in a received skb.
+ */
+struct dccp_ackvec_parsed {
+ u8 *vec,
+ len,
+ nonce:1;
+ struct list_head node;
+};
+
+extern int dccp_ackvec_parsed_add(struct list_head *head,
+ u8 *vec, u8 len, u8 nonce);
+extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks);
#endif /* _ACKVEC_H */
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -135,13 +135,6 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
if (rc)
goto out_invalid_option;
break;
- case DCCPO_ACK_VECTOR_0:
- case DCCPO_ACK_VECTOR_1:
- if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
- break;
- dccp_pr_debug("%s Ack Vector (len=%u)\n", dccp_role(sk),
- len);
- break;
case DCCPO_TIMESTAMP:
if (len != 4)
goto out_invalid_option;
@@ -229,6 +222,16 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
value) != 0)
goto out_invalid_option;
break;
+ case DCCPO_ACK_VECTOR_0:
+ case DCCPO_ACK_VECTOR_1:
+ if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
+ break;
+ /*
+ * Ack vectors are processed by the TX CCID if it is
+ * interested. The RX CCID need not parse Ack Vectors,
+ * since it is only interested in clearing old state.
+ * Fall through.
+ */
case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
opt, len, value - options,
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -345,6 +345,34 @@ free_records:
}
}
+/*
+ * Routines to keep track of Ack Vectors received in an skb
+ */
+int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce)
+{
+ struct dccp_ackvec_parsed *new = kmalloc(sizeof(*new), GFP_ATOMIC);
+
+ if (new == NULL)
+ return -ENOBUFS;
+ new->vec = vec;
+ new->len = len;
+ new->nonce = nonce;
+
+ list_add_tail(&new->node, head);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_add);
+
+void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks)
+{
+ struct dccp_ackvec_parsed *cur, *next;
+
+ list_for_each_entry_safe(cur, next, parsed_chunks, node)
+ kfree(cur);
+ INIT_LIST_HEAD(parsed_chunks);
+}
+EXPORT_SYMBOL_GPL(dccp_ackvec_parsed_cleanup);
+
int __init dccp_ackvec_init(void)
{
dccp_ackvec_slab = kmem_cache_create("dccp_ackvec",
-
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
