MINOR: quic: define quic_cc_algo as const

Each QUIC congestion algorithm is defined as a structure with callbacks
in it. Every quic_conn has a member pointing to the configured
algorithm, inherited from the bind-conf keyword or to the default CUBIC
value.

Convert all these definitions to const. This ensures that there never
will be an accidental modification of a globally shared structure. This
also requires to mark quic_cc_algo field in bind_conf and quic_cc as
const.

include/haproxy/listener-t.h

@@ -186,7 +186,7 @@ struct bind_conf {
 #endif
 #ifdef USE_QUIC
 	struct quic_transport_params quic_params; /* QUIC transport parameters. */
-	struct quic_cc_algo *quic_cc_algo; /* QUIC control congestion algorithm */
+	const struct quic_cc_algo *quic_cc_algo; /* QUIC control congestion algorithm */
 	size_t max_cwnd;                   /* QUIC maximumu congestion control window size (kB) */
 	enum quic_sock_mode quic_mode;     /* QUIC socket allocation strategy */
 #endif

include/haproxy/quic_cc-t.h

@@ -35,13 +35,13 @@
 
 #define QUIC_CC_INFINITE_SSTHESH ((uint32_t)-1)
 
-extern struct quic_cc_algo quic_cc_algo_nr;
-extern struct quic_cc_algo quic_cc_algo_cubic;
-extern struct quic_cc_algo quic_cc_algo_bbr;
-extern struct quic_cc_algo *default_quic_cc_algo;
+extern const struct quic_cc_algo quic_cc_algo_nr;
+extern const struct quic_cc_algo quic_cc_algo_cubic;
+extern const struct quic_cc_algo quic_cc_algo_bbr;
+extern const struct quic_cc_algo *default_quic_cc_algo;
 
 /* Fake algorithm with its fixed window */
-extern struct quic_cc_algo quic_cc_algo_nocc;
+extern const struct quic_cc_algo quic_cc_algo_nocc;
 
 extern unsigned long long last_ts;
 
@@ -90,7 +90,7 @@ enum quic_cc_algo_type {
 struct quic_cc {
 	/* <conn> is there only for debugging purpose. */
 	struct quic_conn *qc;
-	struct quic_cc_algo *algo;
+	const struct quic_cc_algo *algo;
 	uint32_t priv[144];
 };
 

include/haproxy/quic_cc.h

@@ -35,7 +35,7 @@
 #include <haproxy/quic_loss.h>
 #include <haproxy/thread.h>
 
-void quic_cc_init(struct quic_cc *cc, struct quic_cc_algo *algo, struct quic_conn *qc);
+void quic_cc_init(struct quic_cc *cc, const struct quic_cc_algo *algo, struct quic_conn *qc);
 void quic_cc_event(struct quic_cc *cc, struct quic_cc_event *ev);
 void quic_cc_state_trace(struct buffer *buf, const struct quic_cc *cc);
 
@@ -83,7 +83,7 @@ static inline void *quic_cc_priv(const struct quic_cc *cc)
  * which is true for an IPv4 path, if not false for an IPv6 path.
  */
 static inline void quic_cc_path_init(struct quic_cc_path *path, int ipv4, unsigned long max_cwnd,
-                                     struct quic_cc_algo *algo,
+                                     const struct quic_cc_algo *algo,
                                      struct quic_conn *qc)
 {
 	unsigned int max_dgram_sz;

src/cfgparse-quic.c

@@ -101,7 +101,7 @@ static unsigned long parse_window_size(const char *kw, char *value,
 static int bind_parse_quic_cc_algo(char **args, int cur_arg, struct proxy *px,
                                    struct bind_conf *conf, char **err)
 {
-	struct quic_cc_algo *cc_algo;
+	const struct quic_cc_algo *cc_algo;
 	const char *algo = NULL;
 	struct ist algo_ist, arg_ist;
 	char *arg;

src/quic_cc.c

@@ -27,14 +27,14 @@
 #include <haproxy/quic_tune.h>
 #include <haproxy/thread.h>
 
-struct quic_cc_algo *default_quic_cc_algo = &quic_cc_algo_cubic;
+const struct quic_cc_algo *default_quic_cc_algo = &quic_cc_algo_cubic;
 
 /*
  * Initialize <cc> congestion control with <algo> as algorithm depending on <ipv4>
  * a boolean which is true for an IPv4 path.
  */
 void quic_cc_init(struct quic_cc *cc,
-                  struct quic_cc_algo *algo, struct quic_conn *qc)
+                  const struct quic_cc_algo *algo, struct quic_conn *qc)
 {
 	cc->qc = qc;
 	cc->algo = algo;

src/quic_cc_bbr.c

@@ -1531,7 +1531,7 @@ static void bbr_state_cli(struct buffer *buf, const struct quic_cc_path *p)
 	              (ull)bbr->bw, (ull)p->send_quantum, (ull)bbr->pacing_rate);
 }
 
-struct quic_cc_algo quic_cc_algo_bbr = {
+const struct quic_cc_algo quic_cc_algo_bbr = {
 	.type        = QUIC_CC_ALGO_TP_BBR,
 	.init        = bbr_init,
 	.pacing_inter = bbr_pacing_inter,

src/quic_cc_cubic.c

@@ -667,7 +667,7 @@ static void quic_cc_cubic_state_cli(struct buffer *buf, const struct quic_cc_pat
 	              (long long)(path->cwnd - c->last_w_max));
 }
 
-struct quic_cc_algo quic_cc_algo_cubic = {
+const struct quic_cc_algo quic_cc_algo_cubic = {
 	.type        = QUIC_CC_ALGO_TP_CUBIC,
 	.flags       = QUIC_CC_ALGO_FL_OPT_PACING,
 	.init        = quic_cc_cubic_init,

src/quic_cc_newreno.c

@@ -210,7 +210,7 @@ static void quic_cc_nr_event(struct quic_cc *cc, struct quic_cc_event *ev)
 	return quic_cc_nr_state_cbs[nr->state](cc, ev);
 }
 
-struct quic_cc_algo quic_cc_algo_nr = {
+const struct quic_cc_algo quic_cc_algo_nr = {
 	.type        = QUIC_CC_ALGO_TP_NEWRENO,
 	.flags       = QUIC_CC_ALGO_FL_OPT_PACING,
 	.init        = quic_cc_nr_init,

src/quic_cc_nocc.c

@@ -67,7 +67,7 @@ static void quic_cc_nocc_event(struct quic_cc *cc, struct quic_cc_event *ev)
 	return quic_cc_nocc_state_cbs[QUIC_CC_ST_SS](cc, ev);
 }
 
-struct quic_cc_algo quic_cc_algo_nocc = {
+const struct quic_cc_algo quic_cc_algo_nocc = {
 	.type        = QUIC_CC_ALGO_TP_NOCC,
 	.flags       = QUIC_CC_ALGO_FL_OPT_PACING,
 	.init        = quic_cc_nocc_init,

src/quic_conn.c

@@ -1132,7 +1132,7 @@ struct quic_conn *qc_new_conn(void *target,
 	struct listener *l = objt_listener(target);
 	struct server *srv = objt_server(target);
 	struct proxy *prx = l ? l->bind_conf->frontend : __objt_server(target)->proxy;
-	struct quic_cc_algo *cc_algo = NULL;
+	const struct quic_cc_algo *cc_algo = NULL;
 	unsigned int next_actconn = 0, next_sslconn = 0, next_handshake = 0;
 
 	TRACE_ENTER(QUIC_EV_CONN_INIT);