slirp: Allocate/free stack instance dynamically

Allocate the internal slirp state dynamically and provide and call
slirp_cleanup to properly release it after use. This patch finally
unbreaks slirp release and re-instantiation via host_net_* monitor
commands.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 103 insertions, 109 deletions

diff --git a/net.c b/net.c
index 3b20ba5..389be4a 100644
--- a/net.c
+++ b/net.c
@@ -729,11 +729,13 @@ static ssize_t slirp_receive(VLANClientState *vc, const uint8_t *buf, size_t siz
     return size;
 }
 
-static int slirp_in_use;
-
 static void net_slirp_cleanup(VLANClientState *vc)
 {
-    slirp_in_use = 0;
+    SlirpState *s = vc->opaque;
+
+    slirp_cleanup(s->slirp);
+    slirp_state = NULL;
+    qemu_free(s);
 }
 
 static int net_slirp_init(Monitor *mon, VLANState *vlan, const char *model,
@@ -744,137 +746,129 @@ 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 (!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 */
-        struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
-        struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
-        struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
+    /* 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 */
+    struct in_addr host = { .s_addr = htonl(0x0a000202) }; /* 10.0.2.2 */
+    struct in_addr dhcp = { .s_addr = htonl(0x0a00020f) }; /* 10.0.2.15 */
+    struct in_addr dns  = { .s_addr = htonl(0x0a000203) }; /* 10.0.2.3 */
 #ifndef _WIN32
-        struct in_addr smbsrv = { .s_addr = 0 };
+    struct in_addr smbsrv = { .s_addr = 0 };
 #endif
-        char buf[20];
-        uint32_t addr;
-        int shift;
-        char *end;
+    SlirpState *s;
+    char buf[20];
+    uint32_t addr;
+    int shift;
+    char *end;
 
-        if (!tftp_export) {
-            tftp_export = legacy_tftp_prefix;
-        }
-        if (!bootfile) {
-            bootfile = legacy_bootp_filename;
-        }
+    if (!tftp_export) {
+        tftp_export = legacy_tftp_prefix;
+    }
+    if (!bootfile) {
+        bootfile = legacy_bootp_filename;
+    }
 
-        if (vnetwork) {
-            if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
-                if (!inet_aton(vnetwork, &net)) {
-                    return -1;
-                }
-                addr = ntohl(net.s_addr);
-                if (!(addr & 0x80000000)) {
-                    mask.s_addr = htonl(0xff000000); /* class A */
-                } else if ((addr & 0xfff00000) == 0xac100000) {
-                    mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
-                } else if ((addr & 0xc0000000) == 0x80000000) {
-                    mask.s_addr = htonl(0xffff0000); /* class B */
-                } else if ((addr & 0xffff0000) == 0xc0a80000) {
-                    mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
-                } else if ((addr & 0xffff0000) == 0xc6120000) {
-                    mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
-                } else if ((addr & 0xe0000000) == 0xe0000000) {
-                    mask.s_addr = htonl(0xffffff00); /* class C */
-                } else {
-                    mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
-                }
+    if (vnetwork) {
+        if (get_str_sep(buf, sizeof(buf), &vnetwork, '/') < 0) {
+            if (!inet_aton(vnetwork, &net)) {
+                return -1;
+            }
+            addr = ntohl(net.s_addr);
+            if (!(addr & 0x80000000)) {
+                mask.s_addr = htonl(0xff000000); /* class A */
+            } else if ((addr & 0xfff00000) == 0xac100000) {
+                mask.s_addr = htonl(0xfff00000); /* priv. 172.16.0.0/12 */
+            } else if ((addr & 0xc0000000) == 0x80000000) {
+                mask.s_addr = htonl(0xffff0000); /* class B */
+            } else if ((addr & 0xffff0000) == 0xc0a80000) {
+                mask.s_addr = htonl(0xffff0000); /* priv. 192.168.0.0/16 */
+            } else if ((addr & 0xffff0000) == 0xc6120000) {
+                mask.s_addr = htonl(0xfffe0000); /* tests 198.18.0.0/15 */
+            } else if ((addr & 0xe0000000) == 0xe0000000) {
+                mask.s_addr = htonl(0xffffff00); /* class C */
             } else {
-                if (!inet_aton(buf, &net)) {
-                    return -1;
-                }
-                shift = strtol(vnetwork, &end, 10);
-                if (*end != '\0') {
-                    if (!inet_aton(vnetwork, &mask)) {
-                        return -1;
-                    }
-                } else if (shift < 4 || shift > 32) {
+                mask.s_addr = htonl(0xfffffff0); /* multicast/reserved */
+            }
+        } else {
+            if (!inet_aton(buf, &net)) {
+                return -1;
+            }
+            shift = strtol(vnetwork, &end, 10);
+            if (*end != '\0') {
+                if (!inet_aton(vnetwork, &mask)) {
                     return -1;
-                } else {
-                    mask.s_addr = htonl(0xffffffff << (32 - shift));
                 }
+            } else if (shift < 4 || shift > 32) {
+                return -1;
+            } else {
+                mask.s_addr = htonl(0xffffffff << (32 - shift));
             }
-            net.s_addr &= mask.s_addr;
-            host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
-            dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
-            dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
         }
+        net.s_addr &= mask.s_addr;
+        host.s_addr = net.s_addr | (htonl(0x0202) & ~mask.s_addr);
+        dhcp.s_addr = net.s_addr | (htonl(0x020f) & ~mask.s_addr);
+        dns.s_addr  = net.s_addr | (htonl(0x0203) & ~mask.s_addr);
+    }
 
-        if (vhost && !inet_aton(vhost, &host)) {
-            return -1;
-        }
-        if ((host.s_addr & mask.s_addr) != net.s_addr) {
-            return -1;
-        }
+    if (vhost && !inet_aton(vhost, &host)) {
+        return -1;
+    }
+    if ((host.s_addr & mask.s_addr) != net.s_addr) {
+        return -1;
+    }
 
-        if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
-            return -1;
-        }
-        if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
-            dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
-            return -1;
-        }
+    if (vdhcp_start && !inet_aton(vdhcp_start, &dhcp)) {
+        return -1;
+    }
+    if ((dhcp.s_addr & mask.s_addr) != net.s_addr ||
+        dhcp.s_addr == host.s_addr || dhcp.s_addr == dns.s_addr) {
+        return -1;
+    }
 
-        if (vnameserver && !inet_aton(vnameserver, &dns)) {
-            return -1;
-        }
-        if ((dns.s_addr & mask.s_addr) != net.s_addr ||
-            dns.s_addr == host.s_addr) {
-            return -1;
-        }
+    if (vnameserver && !inet_aton(vnameserver, &dns)) {
+        return -1;
+    }
+    if ((dns.s_addr & mask.s_addr) != net.s_addr ||
+        dns.s_addr == host.s_addr) {
+        return -1;
+    }
 
 #ifndef _WIN32
-        if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
-            return -1;
-        }
+    if (vsmbserver && !inet_aton(vsmbserver, &smbsrv)) {
+        return -1;
+    }
 #endif
 
-        s = qemu_mallocz(sizeof(SlirpState));
-        s->slirp = slirp_init(restricted, net, mask, host, vhostname,
-                              tftp_export, bootfile, dhcp, dns, s);
-        slirp_state = s;
+    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;
+    while (slirp_configs) {
+        struct slirp_config_str *config = slirp_configs;
 
-            if (config->flags & SLIRP_CFG_HOSTFWD) {
-                slirp_hostfwd(s, mon, config->str,
-                              config->flags & SLIRP_CFG_LEGACY);
-            } else {
-                slirp_guestfwd(s, mon, config->str,
-                               config->flags & SLIRP_CFG_LEGACY);
-            }
-            slirp_configs = config->next;
-            qemu_free(config);
+        if (config->flags & SLIRP_CFG_HOSTFWD) {
+            slirp_hostfwd(s, mon, config->str,
+                          config->flags & SLIRP_CFG_LEGACY);
+        } else {
+            slirp_guestfwd(s, mon, config->str,
+                           config->flags & SLIRP_CFG_LEGACY);
         }
+        slirp_configs = config->next;
+        qemu_free(config);
+    }
 #ifndef _WIN32
-        if (!smb_export) {
-            smb_export = legacy_smb_export;
-        }
-        if (smb_export) {
-            slirp_smb(s, smb_export, smbsrv);
-        }
-#endif
+    if (!smb_export) {
+        smb_export = legacy_smb_export;
+    }
+    if (smb_export) {
+        slirp_smb(s, smb_export, smbsrv);
     }
+#endif
 
     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;
 }