P2PS: Re-factor p2p_buf_add_service_instance function
Add auxiliary functions to write a single advertised service info record into a wpabuf and to find P2PS wildcard hash in a received hash attribute. Re-factor p2p_buf_add_service_instance() function to allow adding new wildcard types in future commits. Signed-off-by: Max Stepanov <Max.Stepanov@intel.com> Reviewed-by: Ilan Peer <ilan.peer@intel.com>
This commit is contained in:
Max Stepanov
Jouni Malinen
parent
13f6f617ee
commit
c5d3cadbfb
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@ -404,150 +404,229 @@ void p2p_buf_add_advertisement_id(struct wpabuf *buf, u32 id, const u8 *mac)
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}
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static int p2ps_wildcard_hash(struct p2p_data *p2p,
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const u8 *hash, u8 hash_count)
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{
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u8 i;
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const u8 *test = hash;
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for (i = 0; i < hash_count; i++) {
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if (os_memcmp(test, p2p->wild_card_hash, P2PS_HASH_LEN) == 0)
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return 1;
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test += P2PS_HASH_LEN;
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}
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return 0;
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}
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static int p2p_buf_add_service_info(struct wpabuf *buf, struct p2p_data *p2p,
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u32 adv_id, u16 config_methods,
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const char *svc_name, u8 **ie_len, u8 **pos,
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size_t *total_len, u8 *attr_len)
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{
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size_t svc_len;
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size_t remaining;
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size_t info_len;
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svc_len = os_strlen(svc_name);
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info_len = sizeof(adv_id) + sizeof(config_methods) + sizeof(u8) +
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svc_len;
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if (info_len + *total_len > MAX_SVC_ADV_LEN) {
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p2p_dbg(p2p,
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"Unsufficient buffer, failed to add advertised service info");
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return -1;
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}
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if (svc_len > 255) {
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p2p_dbg(p2p,
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"Invalid service name length (%u bytes), failed to add advertised service info",
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(unsigned int) svc_len);
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return -1;
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}
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if (*ie_len) {
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int ie_data_len = (*pos - *ie_len) - 1;
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if (ie_data_len < 0 || ie_data_len > 255) {
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p2p_dbg(p2p,
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"Invalid IE length, failed to add advertised service info");
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return -1;
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}
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remaining = 255 - ie_data_len;
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} else {
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/*
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* Adding new P2P IE header takes 6 extra bytes:
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* - 2 byte IE header (1 byte IE id and 1 byte length)
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* - 4 bytes of IE_VENDOR_TYPE are reduced from 255 below
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*/
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*ie_len = p2p_buf_add_ie_hdr(buf);
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remaining = 255 - 4;
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}
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if (remaining < sizeof(u32) + sizeof(u16) + sizeof(u8)) {
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/*
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* Split adv_id, config_methods, and svc_name_len between two
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* IEs.
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*/
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size_t front = remaining;
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size_t back = sizeof(u32) + sizeof(u16) + sizeof(u8) - front;
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u8 holder[sizeof(u32) + sizeof(u16) + sizeof(u8)];
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WPA_PUT_LE32(holder, adv_id);
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WPA_PUT_BE16(&holder[sizeof(u32)], config_methods);
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holder[sizeof(u32) + sizeof(u16)] = svc_len;
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if (front)
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wpabuf_put_data(buf, holder, front);
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p2p_buf_update_ie_hdr(buf, *ie_len);
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*ie_len = p2p_buf_add_ie_hdr(buf);
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wpabuf_put_data(buf, &holder[front], back);
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remaining = 255 - 4 - (sizeof(u32) + sizeof(u16) + sizeof(u8)) -
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back;
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} else {
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wpabuf_put_le32(buf, adv_id);
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wpabuf_put_be16(buf, config_methods);
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wpabuf_put_u8(buf, svc_len);
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remaining -= sizeof(adv_id) + sizeof(config_methods) +
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sizeof(u8);
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}
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if (remaining < svc_len) {
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/* split svc_name between two or three IEs */
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size_t front = remaining;
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size_t back = svc_len - front;
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if (front)
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wpabuf_put_data(buf, svc_name, front);
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p2p_buf_update_ie_hdr(buf, *ie_len);
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*ie_len = p2p_buf_add_ie_hdr(buf);
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/* In rare cases, we must split across 3 attributes */
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if (back > 255 - 4) {
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wpabuf_put_data(buf, &svc_name[front], 255 - 4);
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back -= 255 - 4;
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front += 255 - 4;
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p2p_buf_update_ie_hdr(buf, *ie_len);
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*ie_len = p2p_buf_add_ie_hdr(buf);
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}
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wpabuf_put_data(buf, &svc_name[front], back);
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remaining = 255 - 4 - back;
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} else {
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wpabuf_put_data(buf, svc_name, svc_len);
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remaining -= svc_len;
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}
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p2p_buf_update_ie_hdr(buf, *ie_len);
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/* set *ie_len to NULL if a new IE has to be added on the next call */
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if (!remaining)
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*ie_len = NULL;
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/* set *pos to point to the next byte to update */
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*pos = wpabuf_put(buf, 0);
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*total_len += info_len;
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WPA_PUT_LE16(attr_len, (u16) *total_len);
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return 0;
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}
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void p2p_buf_add_service_instance(struct wpabuf *buf, struct p2p_data *p2p,
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u8 hash_count, const u8 *hash,
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struct p2ps_advertisement *adv_list)
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{
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struct p2ps_advertisement *adv;
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struct wpabuf *tmp_buf;
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u8 *tag_len = NULL, *ie_len = NULL;
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size_t svc_len = 0, remaining = 0, total_len = 0;
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int p2ps_wildcard;
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size_t total_len;
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struct wpabuf *tmp_buf = NULL;
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u8 *pos, *attr_len, *ie_len = NULL;
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if (!adv_list || !hash)
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if (!adv_list || !hash || !hash_count)
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return;
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p2ps_wildcard = p2ps_wildcard_hash(p2p, hash, hash_count);
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if (p2ps_wildcard)
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goto end;
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/* Allocate temp buffer, allowing for overflow of 1 instance */
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tmp_buf = wpabuf_alloc(MAX_SVC_ADV_IE_LEN + 256 + P2PS_HASH_LEN);
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if (!tmp_buf)
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return;
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/*
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* Attribute data can be split into a number of IEs. Start with the
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* first IE and the attribute headers here.
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*/
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ie_len = p2p_buf_add_ie_hdr(tmp_buf);
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total_len = 0;
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wpabuf_put_u8(tmp_buf, P2P_ATTR_ADVERTISED_SERVICE);
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attr_len = wpabuf_put(tmp_buf, sizeof(u16));
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WPA_PUT_LE16(attr_len, (u16) total_len);
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p2p_buf_update_ie_hdr(tmp_buf, ie_len);
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pos = wpabuf_put(tmp_buf, 0);
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/* add advertised service info of matching services */
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for (adv = adv_list; adv && total_len <= MAX_SVC_ADV_LEN;
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adv = adv->next) {
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u8 count = hash_count;
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const u8 *test = hash;
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u8 i;
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while (count--) {
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/* Check for wildcard */
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if (os_memcmp(test, p2p->wild_card_hash,
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P2PS_HASH_LEN) == 0) {
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total_len = MAX_SVC_ADV_LEN + 1;
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goto wild_hash;
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for (i = 0; i < hash_count; i++) {
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/* exact name hash match */
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if (os_memcmp(test, adv->hash, P2PS_HASH_LEN) == 0 &&
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p2p_buf_add_service_info(tmp_buf, p2p,
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adv->id,
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adv->config_methods,
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adv->svc_name,
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&ie_len, &pos,
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&total_len,
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attr_len)) {
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/*
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* We cannot return all services matching
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* the Probe Request frame hash attribute. In
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* this case, drop currently written entries and
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* return only a single wildcard advertised
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* service info in the Probe Response frame.
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*/
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p2ps_wildcard = 1;
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goto end;
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}
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if (os_memcmp(test, adv->hash, P2PS_HASH_LEN) == 0)
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goto hash_match;
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test += P2PS_HASH_LEN;
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}
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/* No matches found - Skip this Adv Instance */
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continue;
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hash_match:
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if (!tag_len) {
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tag_len = p2p_buf_add_ie_hdr(tmp_buf);
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remaining = 255 - 4;
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if (!ie_len) {
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wpabuf_put_u8(tmp_buf,
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P2P_ATTR_ADVERTISED_SERVICE);
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ie_len = wpabuf_put(tmp_buf, sizeof(u16));
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remaining -= (sizeof(u8) + sizeof(u16));
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}
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}
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svc_len = os_strlen(adv->svc_name);
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if (7 + svc_len + total_len > MAX_SVC_ADV_LEN) {
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/* Can't fit... return wildcard */
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total_len = MAX_SVC_ADV_LEN + 1;
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break;
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}
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if (remaining <= (sizeof(adv->id) +
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sizeof(adv->config_methods))) {
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size_t front = remaining;
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size_t back = (sizeof(adv->id) +
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sizeof(adv->config_methods)) - front;
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u8 holder[sizeof(adv->id) +
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sizeof(adv->config_methods)];
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/* This works even if front or back == 0 */
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WPA_PUT_LE32(holder, adv->id);
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WPA_PUT_BE16(&holder[sizeof(adv->id)],
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adv->config_methods);
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wpabuf_put_data(tmp_buf, holder, front);
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p2p_buf_update_ie_hdr(tmp_buf, tag_len);
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tag_len = p2p_buf_add_ie_hdr(tmp_buf);
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wpabuf_put_data(tmp_buf, &holder[front], back);
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remaining = 255 - (sizeof(adv->id) +
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sizeof(adv->config_methods)) - back;
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} else {
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wpabuf_put_le32(tmp_buf, adv->id);
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wpabuf_put_be16(tmp_buf, adv->config_methods);
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remaining -= (sizeof(adv->id) +
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sizeof(adv->config_methods));
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}
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/* We are guaranteed at least one byte for svc_len */
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wpabuf_put_u8(tmp_buf, svc_len);
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remaining -= sizeof(u8);
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if (remaining < svc_len) {
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size_t front = remaining;
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size_t back = svc_len - front;
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wpabuf_put_data(tmp_buf, adv->svc_name, front);
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p2p_buf_update_ie_hdr(tmp_buf, tag_len);
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tag_len = p2p_buf_add_ie_hdr(tmp_buf);
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/* In rare cases, we must split across 3 attributes */
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if (back > 255 - 4) {
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wpabuf_put_data(tmp_buf,
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&adv->svc_name[front], 255 - 4);
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back -= 255 - 4;
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front += 255 - 4;
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p2p_buf_update_ie_hdr(tmp_buf, tag_len);
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tag_len = p2p_buf_add_ie_hdr(tmp_buf);
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}
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wpabuf_put_data(tmp_buf, &adv->svc_name[front], back);
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remaining = 255 - 4 - back;
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} else {
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wpabuf_put_data(tmp_buf, adv->svc_name, svc_len);
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remaining -= svc_len;
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}
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/* adv_id config_methods svc_string */
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total_len += sizeof(u32) + sizeof(u16) + sizeof(u8) + svc_len;
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}
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if (tag_len)
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p2p_buf_update_ie_hdr(tmp_buf, tag_len);
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if (ie_len)
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WPA_PUT_LE16(ie_len, (u16) total_len);
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wild_hash:
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/* If all fit, return matching instances, otherwise the wildcard */
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if (total_len <= MAX_SVC_ADV_LEN) {
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wpabuf_put_buf(buf, tmp_buf);
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} else {
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char *wild_card = P2PS_WILD_HASH_STR;
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u8 wild_len;
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/* Insert wildcard instance */
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tag_len = p2p_buf_add_ie_hdr(buf);
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end:
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if (p2ps_wildcard) {
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/*
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* Add the attribute with P2PS wildcard if either a wildcard
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* hash was present in a Probe Request frame hash attribute or
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* we failed to add at least one matching advertisement.
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*/
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ie_len = p2p_buf_add_ie_hdr(buf);
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wpabuf_put_u8(buf, P2P_ATTR_ADVERTISED_SERVICE);
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ie_len = wpabuf_put(buf, sizeof(u16));
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attr_len = wpabuf_put(buf, sizeof(u16));
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pos = wpabuf_put(buf, 0);
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total_len = 0;
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wild_len = (u8) os_strlen(wild_card);
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wpabuf_put_le32(buf, 0);
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wpabuf_put_be16(buf, 0);
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wpabuf_put_u8(buf, wild_len);
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wpabuf_put_data(buf, wild_card, wild_len);
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WPA_PUT_LE16(ie_len, 4 + 2 + 1 + wild_len);
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p2p_buf_update_ie_hdr(buf, tag_len);
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p2p_buf_add_service_info(buf, p2p,
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0, 0, P2PS_WILD_HASH_STR,
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&ie_len, &pos, &total_len, attr_len);
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} else if (tmp_buf) {
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/*
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* TODO: An empty attribute is returned if a device is not able
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* to match advertised services. The P2PS specification defines
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* that if the device is not a GO it shall not send a P2PS
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* related Probe Response frame in this case.
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*/
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wpabuf_put_buf(buf, tmp_buf);
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}
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wpabuf_free(tmp_buf);
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