[Qemu-devel] [PATCH 32/41] slirp: Use internal state in interface

[Jan Kiszka]

This now also exports the internal state to the slirp users in qemu,
returning it from slirp_init and expecting it along with service
invocations. Additionally provide an opaque value interface for the
callbacks from slirp into the qemu core.

Signed-off-by: Jan Kiszka <address@hidden>
---

 net.c            |  105 +++++++++++++++++++++++++++++++++---------------------
 slirp/if.c       |    2 +
 slirp/libslirp.h |   35 ++++++++++--------
 slirp/misc.c     |    3 +-
 slirp/slirp.c    |   46 +++++++++++-------------
 slirp/slirp.h    |    1 +
 6 files changed, 108 insertions(+), 84 deletions(-)

diff --git a/net.c b/net.c
index 3ceaf33..5a4791b 100644
--- a/net.c
+++ b/net.c
@@ -677,44 +677,55 @@ struct slirp_config_str {
     int legacy_format;
 };
 
-static int slirp_inited;
+typedef struct SlirpState {
+    VLANClientState *vc;
+    Slirp *slirp;
+} SlirpState;
+
 static struct slirp_config_str *slirp_configs;
 const char *legacy_tftp_prefix;
 const char *legacy_bootp_filename;
-static VLANClientState *slirp_vc;
+static SlirpState *slirp_state;
 
-static void slirp_hostfwd(Monitor *mon, const char *redir_str,
+static void slirp_hostfwd(SlirpState *s, Monitor *mon, const char *redir_str,
                           int legacy_format);
-static void slirp_guestfwd(Monitor *mon, const char *config_str,
+static void slirp_guestfwd(SlirpState *s, Monitor *mon, const char *config_str,
                            int legacy_format);
 
 #ifndef _WIN32
 static const char *legacy_smb_export;
 
-static void slirp_smb(const char *exported_dir, struct in_addr vserver_addr);
+static void slirp_smb(SlirpState *s, const char *exported_dir,
+                      struct in_addr vserver_addr);
 #endif
 
-int slirp_can_output(void)
+int slirp_can_output(void *opaque)
 {
-    return qemu_can_send_packet(slirp_vc);
+    SlirpState *s = opaque;
+
+    return qemu_can_send_packet(s->vc);
 }
 
-void slirp_output(const uint8_t *pkt, int pkt_len)
+void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len)
 {
+    SlirpState *s = opaque;
+
 #ifdef DEBUG_SLIRP
     printf("slirp output:\n");
     hex_dump(stdout, pkt, pkt_len);
 #endif
-    qemu_send_packet(slirp_vc, pkt, pkt_len);
+    qemu_send_packet(s->vc, pkt, pkt_len);
 }
 
 static ssize_t slirp_receive(VLANClientState *vc, const uint8_t *buf, size_t 
size)
 {
+    SlirpState *s = vc->opaque;
+
 #ifdef DEBUG_SLIRP
     printf("slirp input:\n");
     hex_dump(stdout, buf, size);
 #endif
-    slirp_input(buf, size);
+    slirp_input(s->slirp, buf, size);
     return size;
 }
 
@@ -733,11 +744,13 @@ static int net_slirp_init(Monitor *mon, VLANState *vlan, 
const char *model,
                           const char *vnameserver, const char *smb_export,
                           const char *vsmbserver)
 {
+    SlirpState *s = slirp_state;
+
     if (slirp_in_use) {
         /* slirp only supports a single instance so far */
         return -1;
     }
-    if (!slirp_inited) {
+    if (!s) {
         /* default settings according to historic slirp */
         struct in_addr net  = { .s_addr = htonl(0x0a000000) }; /* 10.0.0.0 */
         struct in_addr mask = { .s_addr = htonl(0xff000000) }; /* 255.0.0.0 */
@@ -830,18 +843,19 @@ static int net_slirp_init(Monitor *mon, VLANState *vlan, 
const char *model,
         }
 #endif
 
-        slirp_init(restricted, net, mask, host, vhostname, tftp_export,
-                   bootfile, dhcp, dns);
-        slirp_inited = 1;
+        s = qemu_mallocz(sizeof(SlirpState));
+        s->slirp = slirp_init(restricted, net, mask, host, vhostname,
+                              tftp_export, bootfile, dhcp, dns, s);
+        slirp_state = s;
 
         while (slirp_configs) {
             struct slirp_config_str *config = slirp_configs;
 
             if (config->flags & SLIRP_CFG_HOSTFWD) {
-                slirp_hostfwd(mon, config->str,
+                slirp_hostfwd(s, mon, config->str,
                               config->flags & SLIRP_CFG_LEGACY);
             } else {
-                slirp_guestfwd(mon, config->str,
+                slirp_guestfwd(s, mon, config->str,
                                config->flags & SLIRP_CFG_LEGACY);
             }
             slirp_configs = config->next;
@@ -852,14 +866,14 @@ static int net_slirp_init(Monitor *mon, VLANState *vlan, 
const char *model,
             smb_export = legacy_smb_export;
         }
         if (smb_export) {
-            slirp_smb(smb_export, smbsrv);
+            slirp_smb(s, smb_export, smbsrv);
         }
 #endif
     }
 
-    slirp_vc = qemu_new_vlan_client(vlan, model, name, NULL, slirp_receive,
-                                    NULL, net_slirp_cleanup, NULL);
-    slirp_vc->info_str[0] = '\0';
+    s->vc = qemu_new_vlan_client(vlan, model, name, NULL, slirp_receive, NULL,
+                                 net_slirp_cleanup, s);
+    s->vc->info_str[0] = '\0';
     slirp_in_use = 1;
     return 0;
 }
@@ -873,7 +887,7 @@ void net_slirp_hostfwd_remove(Monitor *mon, const char 
*src_str)
     int is_udp = 0;
     int err;
 
-    if (!slirp_inited) {
+    if (!slirp_state) {
         monitor_printf(mon, "user mode network stack not in use\n");
         return;
     }
@@ -900,7 +914,8 @@ void net_slirp_hostfwd_remove(Monitor *mon, const char 
*src_str)
 
     host_port = atoi(p);
 
-    err = slirp_remove_hostfwd(is_udp, host_addr, host_port);
+    err = slirp_remove_hostfwd(slirp_state->slirp, is_udp,
+                               host_addr, host_port);
 
     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
                    err ? "removed" : "not found");
@@ -910,7 +925,7 @@ void net_slirp_hostfwd_remove(Monitor *mon, const char 
*src_str)
     monitor_printf(mon, "invalid format\n");
 }
 
-static void slirp_hostfwd(Monitor *mon, const char *redir_str,
+static void slirp_hostfwd(SlirpState *s, Monitor *mon, const char *redir_str,
                           int legacy_format)
 {
     struct in_addr host_addr = { .s_addr = INADDR_ANY };
@@ -962,8 +977,8 @@ static void slirp_hostfwd(Monitor *mon, const char 
*redir_str,
         goto fail_syntax;
     }
 
-    if (slirp_add_hostfwd(is_udp, host_addr, host_port,
-                          guest_addr, guest_port) < 0) {
+    if (slirp_add_hostfwd(s->slirp, is_udp, host_addr, host_port, guest_addr,
+                          guest_port) < 0) {
         config_error(mon, "could not set up host forwarding rule '%s'\n",
                      redir_str);
     }
@@ -975,19 +990,19 @@ static void slirp_hostfwd(Monitor *mon, const char 
*redir_str,
 
 void net_slirp_hostfwd_add(Monitor *mon, const char *redir_str)
 {
-    if (!slirp_inited) {
+    if (!slirp_state) {
         monitor_printf(mon, "user mode network stack not in use\n");
         return;
     }
 
-    slirp_hostfwd(mon, redir_str, 0);
+    slirp_hostfwd(slirp_state, mon, redir_str, 0);
 }
 
 void net_slirp_redir(const char *redir_str)
 {
     struct slirp_config_str *config;
 
-    if (!slirp_inited) {
+    if (!slirp_state) {
         config = qemu_malloc(sizeof(*config));
         pstrcpy(config->str, sizeof(config->str), redir_str);
         config->flags = SLIRP_CFG_HOSTFWD | SLIRP_CFG_LEGACY;
@@ -996,7 +1011,7 @@ void net_slirp_redir(const char *redir_str)
         return;
     }
 
-    slirp_hostfwd(NULL, redir_str, 1);
+    slirp_hostfwd(slirp_state, NULL, redir_str, 1);
 }
 
 #ifndef _WIN32
@@ -1034,7 +1049,8 @@ static void smb_exit(void)
     erase_dir(smb_dir);
 }
 
-static void slirp_smb(const char *exported_dir, struct in_addr vserver_addr)
+static void slirp_smb(SlirpState* s, const char *exported_dir,
+                      struct in_addr vserver_addr)
 {
     char smb_conf[1024];
     char smb_cmdline[1024];
@@ -1080,7 +1096,7 @@ static void slirp_smb(const char *exported_dir, struct 
in_addr vserver_addr)
     snprintf(smb_cmdline, sizeof(smb_cmdline), "%s -s %s",
              SMBD_COMMAND, smb_conf);
 
-    if (slirp_add_exec(0, smb_cmdline, vserver_addr, 139) < 0) {
+    if (slirp_add_exec(s->slirp, 0, smb_cmdline, vserver_addr, 139) < 0) {
         fprintf(stderr, "conflicting/invalid smbserver address\n");
         exit(1);
     }
@@ -1096,8 +1112,8 @@ void net_slirp_smb(const char *exported_dir)
         exit(1);
     }
     legacy_smb_export = exported_dir;
-    if (slirp_inited) {
-        slirp_smb(exported_dir, vserver_addr);
+    if (slirp_state) {
+        slirp_smb(slirp_state, exported_dir, vserver_addr);
     }
 }
 
@@ -1107,21 +1123,22 @@ struct GuestFwd {
     CharDriverState *hd;
     struct in_addr server;
     int port;
+    Slirp *slirp;
 };
 
 static int guestfwd_can_read(void *opaque)
 {
     struct GuestFwd *fwd = opaque;
-    return slirp_socket_can_recv(fwd->server, fwd->port);
+    return slirp_socket_can_recv(fwd->slirp, fwd->server, fwd->port);
 }
 
 static void guestfwd_read(void *opaque, const uint8_t *buf, int size)
 {
     struct GuestFwd *fwd = opaque;
-    slirp_socket_recv(fwd->server, fwd->port, buf, size);
+    slirp_socket_recv(fwd->slirp, fwd->server, fwd->port, buf, size);
 }
 
-static void slirp_guestfwd(Monitor *mon, const char *config_str,
+static void slirp_guestfwd(SlirpState *s, Monitor *mon, const char *config_str,
                            int legacy_format)
 {
     struct in_addr server = { .s_addr = 0 };
@@ -1169,8 +1186,9 @@ static void slirp_guestfwd(Monitor *mon, const char 
*config_str,
     }
     fwd->server = server;
     fwd->port = port;
+    fwd->slirp = s->slirp;
 
-    if (slirp_add_exec(3, fwd->hd, server, port) < 0) {
+    if (slirp_add_exec(s->slirp, 3, fwd->hd, server, port) < 0) {
         config_error(mon, "conflicting/invalid host:port in guest forwarding "
                      "rule '%s'\n", config_str);
         qemu_free(fwd);
@@ -1186,8 +1204,13 @@ static void slirp_guestfwd(Monitor *mon, const char 
*config_str,
 
 void do_info_usernet(Monitor *mon)
 {
-    monitor_printf(mon, "VLAN %d (%s):\n", slirp_vc->vlan->id, slirp_vc->name);
-    slirp_connection_info(mon);
+    SlirpState *s = slirp_state;
+
+    if (!s) {
+        return;
+    }
+    monitor_printf(mon, "VLAN %d (%s):\n", s->vc->vlan->id, s->vc->name);
+    slirp_connection_info(s->slirp, mon);
 }
 
 #endif /* CONFIG_SLIRP */
@@ -2482,7 +2505,7 @@ int net_client_init(Monitor *mon, const char *device, 
const char *p)
         qemu_free(smb_export);
         qemu_free(vsmbsrv);
     } else if (!strcmp(device, "channel")) {
-        if (!slirp_inited) {
+        if (!slirp_state) {
             struct slirp_config_str *config;
 
             config = qemu_malloc(sizeof(*config));
@@ -2491,7 +2514,7 @@ int net_client_init(Monitor *mon, const char *device, 
const char *p)
             config->next = slirp_configs;
             slirp_configs = config;
         } else {
-            slirp_guestfwd(mon, p, 1);
+            slirp_guestfwd(slirp_state, mon, p, 1);
         }
         ret = 0;
     } else
diff --git a/slirp/if.c b/slirp/if.c
index 75b15e4..0f04e13 100644
--- a/slirp/if.c
+++ b/slirp/if.c
@@ -162,7 +162,7 @@ if_start(Slirp *slirp)
 
  again:
         /* check if we can really output */
-        if (!slirp_can_output())
+        if (!slirp_can_output(slirp->opaque))
             return;
 
        /*
diff --git a/slirp/libslirp.h b/slirp/libslirp.h
index 3bda691..521de3e 100644
--- a/slirp/libslirp.h
+++ b/slirp/libslirp.h
@@ -8,11 +8,11 @@
 struct Slirp;
 typedef struct Slirp Slirp;
 
-void slirp_init(int restricted, struct in_addr vnetwork,
-                struct in_addr vnetmask, struct in_addr vhost,
-                const char *vhostname, const char *tftp_path,
-                const char *bootfile, struct in_addr vdhcp_start,
-                struct in_addr vnameserver);
+Slirp *slirp_init(int restricted, struct in_addr vnetwork,
+                  struct in_addr vnetmask, struct in_addr vhost,
+                  const char *vhostname, const char *tftp_path,
+                  const char *bootfile, struct in_addr vdhcp_start,
+                  struct in_addr vnameserver, void *opaque);
 
 void slirp_select_fill(int *pnfds,
                        fd_set *readfds, fd_set *writefds, fd_set *xfds);
@@ -20,23 +20,26 @@ void slirp_select_fill(int *pnfds,
 void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds,
                        int select_error);
 
-void slirp_input(const uint8_t *pkt, int pkt_len);
+void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len);
 
 /* you must provide the following functions: */
-int slirp_can_output(void);
-void slirp_output(const uint8_t *pkt, int pkt_len);
+int slirp_can_output(void *opaque);
+void slirp_output(void *opaque, const uint8_t *pkt, int pkt_len);
 
-int slirp_add_hostfwd(int is_udp, struct in_addr host_addr, int host_port,
+int slirp_add_hostfwd(Slirp *slirp, int is_udp,
+                      struct in_addr host_addr, int host_port,
                       struct in_addr guest_addr, int guest_port);
-int slirp_remove_hostfwd(int is_udp, struct in_addr host_addr, int host_port);
-int slirp_add_exec(int do_pty, const void *args, struct in_addr guest_addr,
-                   int guest_port);
+int slirp_remove_hostfwd(Slirp *slirp, int is_udp,
+                         struct in_addr host_addr, int host_port);
+int slirp_add_exec(Slirp *slirp, int do_pty, const void *args,
+                   struct in_addr guest_addr, int guest_port);
 
-void slirp_connection_info(Monitor *mon);
+void slirp_connection_info(Slirp *slirp, Monitor *mon);
 
-void slirp_socket_recv(struct in_addr guest_addr, int guest_port,
-                       const uint8_t *buf, int size);
-size_t slirp_socket_can_recv(struct in_addr guest_addr, int guest_port);
+void slirp_socket_recv(Slirp *slirp, struct in_addr guest_addr,
+                       int guest_port, const uint8_t *buf, int size);
+size_t slirp_socket_can_recv(Slirp *slirp, struct in_addr guest_addr,
+                             int guest_port);
 
 #else /* !CONFIG_SLIRP */
 
diff --git a/slirp/misc.c b/slirp/misc.c
index c2b66fd..e9f08fd 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -370,7 +370,7 @@ fd_block(int fd)
 #endif
 }
 
-void slirp_connection_info(Monitor *mon)
+void slirp_connection_info(Slirp *slirp, Monitor *mon)
 {
     const char * const tcpstates[] = {
         [TCPS_CLOSED]       = "CLOSED",
@@ -385,7 +385,6 @@ void slirp_connection_info(Monitor *mon)
         [TCPS_FIN_WAIT_2]   = "FIN_WAIT_2",
         [TCPS_TIME_WAIT]    = "TIME_WAIT",
     };
-    Slirp *slirp = &slirp_instance;
     struct in_addr dst_addr;
     struct sockaddr_in src;
     socklen_t src_len;
diff --git a/slirp/slirp.c b/slirp/slirp.c
index 25bc8a4..7e86124 100644
--- a/slirp/slirp.c
+++ b/slirp/slirp.c
@@ -187,11 +187,11 @@ static void slirp_init_once(void)
 static void slirp_state_save(QEMUFile *f, void *opaque);
 static int slirp_state_load(QEMUFile *f, void *opaque, int version_id);
 
-void slirp_init(int restricted, struct in_addr vnetwork,
-                struct in_addr vnetmask, struct in_addr vhost,
-                const char *vhostname, const char *tftp_path,
-                const char *bootfile, struct in_addr vdhcp_start,
-                struct in_addr vnameserver)
+Slirp *slirp_init(int restricted, struct in_addr vnetwork,
+                  struct in_addr vnetmask, struct in_addr vhost,
+                  const char *vhostname, const char *tftp_path,
+                  const char *bootfile, struct in_addr vdhcp_start,
+                  struct in_addr vnameserver, void *opaque)
 {
     Slirp *slirp = &slirp_instance;
 
@@ -226,7 +226,11 @@ void slirp_init(int restricted, struct in_addr vnetwork,
     slirp->vdhcp_startaddr = vdhcp_start;
     slirp->vnameserver_addr = vnameserver;
 
+    slirp->opaque = opaque;
+
     register_savevm("slirp", 0, 2, slirp_state_save, slirp_state_load, slirp);
+
+    return slirp;
 }
 
 #define CONN_CANFSEND(so) (((so)->so_state & 
(SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
@@ -635,7 +639,7 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int 
pkt_len)
             rah->ar_sip = ah->ar_tip;
             memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
             rah->ar_tip = ah->ar_sip;
-            slirp_output(arp_reply, sizeof(arp_reply));
+            slirp_output(slirp->opaque, arp_reply, sizeof(arp_reply));
         }
         break;
     case ARPOP_REPLY:
@@ -650,9 +654,8 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int 
pkt_len)
     }
 }
 
-void slirp_input(const uint8_t *pkt, int pkt_len)
+void slirp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len)
 {
-    Slirp *slirp = &slirp_instance;
     struct mbuf *m;
     int proto;
 
@@ -724,7 +727,7 @@ void if_encap(Slirp *slirp, const uint8_t *ip_data, int 
ip_data_len)
         /* target IP */
         rah->ar_tip = iph->ip_dst.s_addr;
         slirp->client_ipaddr = iph->ip_dst;
-        slirp_output(arp_req, sizeof(arp_req));
+        slirp_output(slirp->opaque, arp_req, sizeof(arp_req));
     } else {
         memcpy(eh->h_dest, slirp->client_ethaddr, ETH_ALEN);
         memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 4);
@@ -732,14 +735,14 @@ void if_encap(Slirp *slirp, const uint8_t *ip_data, int 
ip_data_len)
         memcpy(&eh->h_source[2], &slirp->vhost_addr, 4);
         eh->h_proto = htons(ETH_P_IP);
         memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
-        slirp_output(buf, ip_data_len + ETH_HLEN);
+        slirp_output(slirp->opaque, buf, ip_data_len + ETH_HLEN);
     }
 }
 
 /* Drop host forwarding rule, return 0 if found. */
-int slirp_remove_hostfwd(int is_udp, struct in_addr host_addr, int host_port)
+int slirp_remove_hostfwd(Slirp *slirp, int is_udp, struct in_addr host_addr,
+                         int host_port)
 {
-    Slirp *slirp = &slirp_instance;
     struct socket *so;
     struct socket *head = (is_udp ? &slirp->udb : &slirp->tcb);
     struct sockaddr_in addr;
@@ -761,11 +764,9 @@ int slirp_remove_hostfwd(int is_udp, struct in_addr 
host_addr, int host_port)
     return -1;
 }
 
-int slirp_add_hostfwd(int is_udp, struct in_addr host_addr, int host_port,
-                      struct in_addr guest_addr, int guest_port)
+int slirp_add_hostfwd(Slirp *slirp, int is_udp, struct in_addr host_addr,
+                      int host_port, struct in_addr guest_addr, int guest_port)
 {
-    Slirp *slirp = &slirp_instance;
-
     if (!guest_addr.s_addr) {
         guest_addr = slirp->vdhcp_startaddr;
     }
@@ -781,11 +782,9 @@ int slirp_add_hostfwd(int is_udp, struct in_addr 
host_addr, int host_port,
     return 0;
 }
 
-int slirp_add_exec(int do_pty, const void *args, struct in_addr guest_addr,
-                   int guest_port)
+int slirp_add_exec(Slirp *slirp, int do_pty, const void *args,
+                   struct in_addr guest_addr, int guest_port)
 {
-    Slirp *slirp = &slirp_instance;
-
     if (!guest_addr.s_addr) {
         guest_addr.s_addr = slirp->vnetwork_addr.s_addr |
             (htonl(0x0204) & ~slirp->vnetwork_mask.s_addr);
@@ -824,9 +823,9 @@ slirp_find_ctl_socket(Slirp *slirp, struct in_addr 
guest_addr, int guest_port)
     return NULL;
 }
 
-size_t slirp_socket_can_recv(struct in_addr guest_addr, int guest_port)
+size_t slirp_socket_can_recv(Slirp *slirp, struct in_addr guest_addr,
+                             int guest_port)
 {
-       Slirp *slirp = &slirp_instance;
        struct iovec iov[2];
        struct socket *so;
 
@@ -841,10 +840,9 @@ size_t slirp_socket_can_recv(struct in_addr guest_addr, 
int guest_port)
        return sopreprbuf(so, iov, NULL);
 }
 
-void slirp_socket_recv(struct in_addr guest_addr, int guest_port,
+void slirp_socket_recv(Slirp *slirp, struct in_addr guest_addr, int guest_port,
                        const uint8_t *buf, int size)
 {
-    Slirp *slirp = &slirp_instance;
     int ret;
     struct socket *so = slirp_find_ctl_socket(slirp, guest_addr, guest_port);
 
diff --git a/slirp/slirp.h b/slirp/slirp.h
index b1e8d4e..cb1a746 100644
--- a/slirp/slirp.h
+++ b/slirp/slirp.h
@@ -256,6 +256,7 @@ struct Slirp {
     char *tftp_prefix;
     struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
 
+    void *opaque;
 };
 
 extern Slirp slirp_instance;