/**
* Extend a Name with a new version stamp
* @param h is the the ccn handle.
* May be NULL. This procedure does not use the connection.
* @param name is a ccnb-encoded Name prefix. By default it gets extended
* in-place with one additional Component that conforms to the
* versioning profile and is based on the supplied time, unless a
* version component is already present.
* @param versioning_flags modifies the default behavior:
* CCN_V_REPLACE causes the last component to be replaced if it
* appears to be a version stamp. If CCN_V_HIGH is set as well, an
* attempt will be made to generate a new version stamp that is
* later than the existing one, or to return an error.
* CCN_V_NOW bases the version on the current time rather than the
* supplied time.
* CCN_V_NESTOK will allow the new version component to be appended
* even if there is one there (this makes no difference if CCN_V_REPLACE
* is also set).
* @param secs is the desired time, in seconds since epoch
* (ignored if CCN_V_NOW is set).
* @param nsecs is the number of nanoseconds.
* @returns -1 for error, 0 for success.
*/
int
ccn_create_version(struct ccn *h, struct ccn_charbuf *name,
int versioning_flags, intmax_t secs, int nsecs)
{
size_t i;
size_t j;
size_t lc = 0;
size_t oc = 0;
int n;
struct ccn_indexbuf *nix = NULL;
int myres = -1;
int already_versioned = 0;
int ok_flags = (CCN_V_REPLACE | CCN_V_HIGH | CCN_V_NOW | CCN_V_NESTOK);
// XXX - right now we ignore h, but in the future we may use it to try to avoid non-monotonicies in the versions.
nix = ccn_indexbuf_create();
n = ccn_name_split(name, nix);
if (n < 0)
goto Finish;
if ((versioning_flags & ~ok_flags) != 0)
goto Finish;
/* Check for existing version component */
if (n >= 1) {
oc = nix->buf[n-1];
lc = nix->buf[n] - oc;
if (lc <= 11 && lc >= 6 && name->buf[oc + 2] == CCN_MARKER_VERSION)
already_versioned = 1;
}
myres = 0;
if (already_versioned &&
(versioning_flags & (CCN_V_REPLACE | CCN_V_NESTOK)) == 0)
goto Finish;
name->length -= 1; /* Strip name closer */
i = name->length;
myres |= ccn_charbuf_append_tt(name, CCN_DTAG_Component, CCN_DTAG);
if ((versioning_flags & CCN_V_NOW) != 0)
myres |= ccnb_append_now_blob(name, CCN_MARKER_VERSION);
else {
myres |= ccnb_append_timestamp_blob(name, CCN_MARKER_VERSION, secs, nsecs);
}
myres |= ccn_charbuf_append_closer(name); /* </Component> */
if (myres < 0) {
name->length = i;
goto CloseName;
}
j = name->length;
if (already_versioned && (versioning_flags & CCN_V_REPLACE) != 0) {
oc = nix->buf[n-1];
lc = nix->buf[n] - oc;
if ((versioning_flags & CCN_V_HIGH) != 0 &&
memcmp(name->buf + oc, name->buf + i, j - i) > 0) {
/* Supplied version is in the future. */
name->length = i;
// XXX - we could try harder to make this work, for now just error out
myres = -1;
goto CloseName;
}
memmove(name->buf + oc, name->buf + i, j - i);
name->length -= lc;
}
CloseName:
myres |= ccn_charbuf_append_closer(name); /* </Name> */
Finish:
myres = (myres < 0) ? -1 : 0;
ccn_indexbuf_destroy(&nix);
return(myres);
}
/**
* Create SignedInfo.
*
*
* @param c is used to hold the result.
* @param publisher_key_id points to the digest of the publisher key id.
* @param publisher_key_id_size is the size in bytes(32) of the pub key digest
* @param timestamp holds the timestamp, as a ccnb-encoded blob, or is NULL
to use the current time.
* @param type indicates the Type of the ContentObject.
* @param freshness is the FreshnessSeconds value, or -1 to omit.
* @param finalblockid holds the FinalBlockID, as a ccnb-encoded blob, or is
NULL to omit.
* @param key_locator is the ccnb-encoded KeyLocator element, or NULL to omit.
* @returns 0 for success or -1 for error.
*/
int
ccn_signed_info_create(struct ccn_charbuf *c,
const void *publisher_key_id, /* input, sha256 hash */
size_t publisher_key_id_size, /* input, 32 for sha256 hashes */
const struct ccn_charbuf *timestamp,/* input ccnb blob, NULL for "now" */
enum ccn_content_type type, /* input */
int freshness, /* input, -1 means omit */
const struct ccn_charbuf *finalblockid, /* input, NULL means omit */
const struct ccn_charbuf *key_locator) /* input, optional, ccnb encoded */
{
int res = 0;
const char fakepubkeyid[32] = {0};
if (publisher_key_id != NULL && publisher_key_id_size != 32)
return(-1);
res |= ccn_charbuf_append_tt(c, CCN_DTAG_SignedInfo, CCN_DTAG);
res |= ccn_charbuf_append_tt(c, CCN_DTAG_PublisherPublicKeyDigest, CCN_DTAG);
if (publisher_key_id != NULL) {
res |= ccn_charbuf_append_tt(c, publisher_key_id_size, CCN_BLOB);
res |= ccn_charbuf_append(c, publisher_key_id, publisher_key_id_size);
} else {
/* XXX - obtain the default publisher key id and append it */
res |= ccn_charbuf_append_tt(c, sizeof(fakepubkeyid), CCN_BLOB);
res |= ccn_charbuf_append(c, fakepubkeyid, sizeof(fakepubkeyid));
}
res |= ccn_charbuf_append_closer(c);
res |= ccn_charbuf_append_tt(c, CCN_DTAG_Timestamp, CCN_DTAG);
if (timestamp != NULL)
res |= ccn_charbuf_append_charbuf(c, timestamp);
else
res |= ccnb_append_now_blob(c, CCN_MARKER_NONE);
res |= ccn_charbuf_append_closer(c);
if (type != CCN_CONTENT_DATA) {
res |= ccn_charbuf_append_tt(c, CCN_DTAG_Type, CCN_DTAG);
res |= ccn_charbuf_append_tt(c, 3, CCN_BLOB);
res |= ccn_charbuf_append_value(c, type, 3);
res |= ccn_charbuf_append_closer(c);
}
if (freshness >= 0)
res |= ccnb_tagged_putf(c, CCN_DTAG_FreshnessSeconds, "%d", freshness);
if (finalblockid != NULL) {
res |= ccn_charbuf_append_tt(c, CCN_DTAG_FinalBlockID, CCN_DTAG);
res |= ccn_charbuf_append_charbuf(c, finalblockid);
res |= ccn_charbuf_append_closer(c);
}
if (key_locator != NULL) {
/* key_locator is a sub-type that should already be encoded */
res |= ccn_charbuf_append_charbuf(c, key_locator);
}
res |= ccn_charbuf_append_closer(c);
return(res == 0 ? 0 : -1);
}
