+int cfg80211_get_p2p_attr(const u8 *ies, unsigned int len,
+ enum ieee80211_p2p_attr_id attr,
+ u8 *buf, unsigned int bufsize)
+{
+ u8 *out = buf;
+ u16 attr_remaining = 0;
+ bool desired_attr = false;
+ u16 desired_len = 0;
+
+ while (len > 0) {
+ unsigned int iedatalen;
+ unsigned int copy;
+ const u8 *iedata;
+
+ if (len < 2)
+ return -EILSEQ;
+ iedatalen = ies[1];
+ if (iedatalen + 2 > len)
+ return -EILSEQ;
+
+ if (ies[0] != WLAN_EID_VENDOR_SPECIFIC)
+ goto cont;
+
+ if (iedatalen < 4)
+ goto cont;
+
+ iedata = ies + 2;
+
+ /* check WFA OUI, P2P subtype */
+ if (iedata[0] != 0x50 || iedata[1] != 0x6f ||
+ iedata[2] != 0x9a || iedata[3] != 0x09)
+ goto cont;
+
+ iedatalen -= 4;
+ iedata += 4;
+
+ /* check attribute continuation into this IE */
+ copy = min_t(unsigned int, attr_remaining, iedatalen);
+ if (copy && desired_attr) {
+ desired_len += copy;
+ if (out) {
+ memcpy(out, iedata, min(bufsize, copy));
+ out += min(bufsize, copy);
+ bufsize -= min(bufsize, copy);
+ }
+
+
+ if (copy == attr_remaining)
+ return desired_len;
+ }
+
+ attr_remaining -= copy;
+ if (attr_remaining)
+ goto cont;
+
+ iedatalen -= copy;
+ iedata += copy;
+
+ while (iedatalen > 0) {
+ u16 attr_len;
+
+ /* P2P attribute ID & size must fit */
+ if (iedatalen < 3)
+ return -EILSEQ;
+ desired_attr = iedata[0] == attr;
+ attr_len = get_unaligned_le16(iedata + 1);
+ iedatalen -= 3;
+ iedata += 3;
+
+ copy = min_t(unsigned int, attr_len, iedatalen);
+
+ if (desired_attr) {
+ desired_len += copy;
+ if (out) {
+ memcpy(out, iedata, min(bufsize, copy));
+ out += min(bufsize, copy);
+ bufsize -= min(bufsize, copy);
+ }
+
+ if (copy == attr_len)
+ return desired_len;
+ }
+
+ iedata += copy;
+ iedatalen -= copy;
+ attr_remaining = attr_len - copy;
+ }
+
+ cont:
+ len -= ies[1] + 2;
+ ies += ies[1] + 2;
+ }
+
+ if (attr_remaining && desired_attr)
+ return -EILSEQ;
+
+ return -ENOENT;
+}
+EXPORT_SYMBOL(cfg80211_get_p2p_attr);
+