can't determine encap-header location until after HDLC'ing

Tested with F5 HDLC and non-HLDC

Signed-off-by: Daniel Lenski <dlenski@gmail.com>

diff --git a/ppp.c b/ppp.c
index a5be9e6b00c334a03d411b3945f7e7e91d845ab3..549f91d6bd5a8d41575ed9e022e664879c4847e5 100644 (file)
--- a/ppp.c
+++ b/ppp.c
@@ -685,7 +685,7 @@ static int handle_state_transition(struct openconnect_info *vpninfo, int *timeou
        return 0;
 }
 
-static inline unsigned char *add_ppp_header(struct pkt *p, struct oc_ppp *ppp, int proto) {
+static inline void add_ppp_header(struct pkt *p, struct oc_ppp *ppp, int proto) {
        int n = 0;
        /* XX: store PPP header, in reverse */
        p->data[--n] = proto & 0xff;
@@ -695,11 +695,7 @@ static inline unsigned char *add_ppp_header(struct pkt *p, struct oc_ppp *ppp, i
                p->data[--n] = 0x03; /* Control */
                p->data[--n] = 0xff; /* Address */
        }
-
-       /* reserve space for pre-PPP encapsulation header */
        p->ppp.hlen = -n;
-       p->ppp.hlen += ppp->encap_len;
-       return (p->data - p->ppp.hlen);
 }
 
 int ppp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
@@ -976,8 +972,10 @@ int ppp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
        }
 
        if (this) {
-               /* Add PPP header and reserve space for pre-PPP encapsulation header */
-               unsigned char *eh = add_ppp_header(this, ppp, proto);
+               unsigned char *eh;
+
+               /* Add PPP header */
+               add_ppp_header(this, ppp, proto);
 
                /* XX: Copy the whole packet into new HDLC'ed packet if needed */
                if (ppp->hdlc) {
@@ -991,16 +989,18 @@ int ppp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
                }
 
                /* Add pre-PPP encapsulation header */
+               eh = this->data - this->ppp.hlen - ppp->encap_len;
                switch (ppp->encap) {
                case PPP_ENCAP_F5:
                        store_be16(eh, 0xf500);
-                       store_be16(eh + 2, this->len + this->ppp.hlen - 4);
+                       store_be16(eh + 2, this->len + this->ppp.hlen);
                        break;
                case PPP_ENCAP_NX_HDLC:
                        /* XX: header is simply the number of bytes on the wire (excluding itself) */
-                       store_be32(eh, this->len + this->ppp.hlen - 4);
+                       store_be32(eh, this->len + this->ppp.hlen);
                        break;
                }
+               this->ppp.hlen += ppp->encap_len;
 
                vpn_progress(vpninfo, PRG_TRACE,
                             _("Sending proto 0x%04x packet (%d bytes total)\n"),